LIMP MODE Q&A

LIMP HOME MODE

When I initially bought my VW Polo 2.0L she was a thrill to drive. Her speed was instant, cornering was really good and road holding never better. She was a joy to drive, very unlike my VW Golf II, but then I started getting car troubles,  which were many and varied. My first encounter with VW agents was a disaster. After they "repaired" my EPC fault they charged me a ridiculous sum of money, only to experience the same EPC problem the following day.  After speaking to several of their mechanics, who collectively were unable to fix my car, I came to realize  that I was either far more knowledgeable about automotive electronics than all of them put together, or they knew very little about electronics.  This just put me off the agents completely and when I took my Polo to independent mechanical workshops,  I found the same to be true. I still remember how lost I felt when my VW Polo went into limp mode the first time and the second and the third and the fourth. I felt lost, stuck on the freeway, late for meetings, frustrated and miserable because I couldn't repair her like I did the VW Golf II due to the fact that the Polo had OBD-II. I  thought my VW Polo to be unreliable, there was a point that I feared driver her at night, and later started to hate  even diving the Polo.  I was literally on the verge of setting her alight. But them I decided to buy a Ross Tech cable and downloaded their VCDS and my Polo is a joy to  drive once again. The rest of this blog is devoted to 10 vehicles owners who have experiences similar trouble with their VAG vehicles ranging from Drive by wire problems, to EPC trouble, to DTC trouble Codes to CAN-Bus-issues to name but a few. 

DRIVE BY WIRE
Steve sent this:- Had the problem of no power, tried the technique described in your blog (disconnect battery, wait, reconnect, turn ignition key, wait, turn off, turn engine on, wait, press throttle...) - and it worked beautifully. Many thanks for your help, very much appreciated - particularly as you've probably save me many pounds. 

QUESTION? - DRIVE BY WIRE
Anonymous sent this:- I have a '07 Polo 1.4 16v BUD. I don't have any lights on the dash, but the engine seems really weak through mid revs and is using a bit too much fuel. When I hook up my OBDII there are no faults recorded but when I view the throttle position in real time it doesn't seem to open in a linear manner. As I press the pedal on the road, the throttle valve seems to open slower than the position of  the pedal. eg; 50% pedal = 30% throttle position, 80% pedal = 35% throttle, 95% pedal = 40% throttle, 100% Pedal = 100% throttle. As you can see WOT does give WOT at the throttle body, but I don't generally drive with my foot planted on the floor. I am confused why it does this as you would expect the throttle body to open the same amount as the pedal, could it need alignment? I am loathed to take it to the VW dealer for fault diagno$i$ so if anyone has any ideas????  Thanks 

ANSWER!
On drive by wire model vehicles the throttle doesn't open like legacy cable throttles because its electronically controlled. 

DRIVE BY WIRE
Durell  Dunn  left this:- I am currently experiencing the same problem with my 2003 polo,1.4. The car goes into limp mode and on some occasions switches off in traffic, hectic ! I will use your method. Thank you for saving me from going to a VW dealership, all I can do at this stage is do and hope 

DRIVE BY WIRE
Loci sent this:- Hi. I have a problem with my Volkswagen Polo 1.4 Tdi. It seems to have a good start but after I drive for around 35 minutes it loses the power so I could not pass 2000 giro. Thank you for your suggestions.

QUESTION? - DRIVE BY WIRE 
Anonymous asked:- My car is a polo 1.4 2012 model. When I start the car the EPC light switch on then I put gear to move the car but it limbs then I switch it off then start it again then the EPC light does not switch on then off I go... What could be wrong? 

ANSWER!
The trouble can be one of many things, among which are your accelerator pedal, throttle body, knock sensor, Fuel pump pressure, even a loose fuel cap. You need to check through each systematically but for that you at least need a scan of your vehicle.

ENGINE LIGHT COMES ON
Lee Kyprian left this:- Everyone who has ever owned a car has experienced the confusion and even panic which can arrive when your check engine light suddenly comes on.

QUESTION? VW ELECTRONIC POWER CONTROL
Abror Isoqov sent this:- Hello. My car is VW Golf 1.6 16v and I have a problem with acceleration it has no enough power. It accelerates very slow and at 5th gear it can get max 130 km/h. At neutral position when engine gets about 5000 rpm the EPC light comes on. After restarting the engine it goes off. Tester didn't determine any trouble codes. What can cause for this problem. I went about 7-8 auto services but any of them could help. But I didn't go to VW dealer because it will be very expensive. last time they charged me $125 just for diagnostic.  Please help me with this issue.   

ANSWER!
What you explaining is limp mode and everything else seems very odd. Because by the time the EPC light does go on, a DTC is already set which any scan tool should be able to retrieve. Unless there is a problem with you DLC wiring, so that communication between vehicle and scan tool is erroneous.

VW ERROR CODES
Steve Cain sent this:- Hi, vw polo 1.4tdi 2003, AMF engine code,  problem is that when driving at any speed, car looses all power, engine stuck on 1200 rpm, throttle pedal no response, glow plug heating light flashes, switch off & switch back on straight away, car drives normally, no warning lights. Can you shed any light on this problem, (driving my wife mad). Thanks, Steve 

ANSWER!
I have covered this problem quite substantially in previous blogs and it in your interest to ready through them.

WON'T REV
Anonymous sent this:- My VW Jetta 2002 1.8t stopped me on the highway and it refused to rev and the mechanic says it is the brain box. I don't understand is he correct?

ANSWER!
Yes he is correct, problem lies in the ECM circuit but not necessarily the ECM itself. Dude you need to get your car scanned to get a better idea of  the actual problem.

CAN-BUS
Hi! I read your blogs and saw writings from you  about the CAN bus protocol. I have a problem to understand something on my cars OBD connector and the CAN bus line. Can you please help me maybe? Can we talk about? When I connect my 2 channel  DSO to the OBD connector pin 6 and pin 14 ( CAN-H and L ) and pin 5 (GND) on my VW Polo 1.4D year 2003 I got this signal what I posted right now. But, when I do the same think on my Renault Clio 1.5DCI year 2003 I got the right CAN signal.  

ANSWER! 
The likely hood is that your VW Polo isn't CAN compliant because its still a 2003 and used KWP-1281 and KWP-2000 protocols.  All VW's after 2008 is fully CAN compliant.

ECM POWER RELAY OPEN CIRCUIT

ECM POWER RELAY OPEN CIRCUIT 

17069 - P0685 ERROR

Electrical problems seems to stymie everyone, but repairing an electrical fault can be fairy simple if traced logically. The above error relates to a relay. Relays are just remote switches. Audi, Volkswagen, Seat and Skoda relays can give a fair amount of trouble because its push-in spade terminals may corrode, or they may even pop out of the relay plate due to shaking on bumpy roads. Their contacts may overheat and fuse together, or the spring inside may snap or jump off. Its solenoid can even burn out. Or its plastic enclosure may melt and block the switch mechanism from moving. But these are not the only faults related to relays.

Question?

Will Wallace shared this: 
Hey, I am a bit desperate for advice here, so reaching out.  Having a problem with my GF's VW Polo 1.4L 16V (BUD Engine). I have had to jump start this vehicle every 4 days or so. It will run fine, and then after about 4 days won't start, it either makes a clicking sound (sounds like a relay and wont turn over) when trying to start or starts beeping with the Engine light showing and the Park Brake light flashing (and won't make any sound when turning key). 

Connecting up a scan tool brings up Error 17069. Looking around the forums it seems like quite a common fault, with no real definitive solution. The battery measures 12V without the key in and then goes down to 8.5v when  the key is in and ignition ready. I've tried disconnecting the Plus Battery terminal and connecting a Volt meter to it and the battery post + and setting the DMM to Amps but its not coming up with any amp draw which I think is good (Not sure if I am doing this correctly though). It seems like something is draining the battery or the alternator isn't  charging it properly? I had a battery test done at a auto store and they said  it was fine and the alternator was charging it properly which is bizarre. I have posted this as it seems like a common fault and would be good to get  some advice. Thanks in advance.

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Answer!

Greetings  Will Wallace, so sorry to hear that you having so much grief with your Girlfriend's car. As much as I would like to help you, remote diagnosis without a full scan cannot always be accurate but I hope my thoughts on the matter may steer you in the right direction. The fact the you have  a scan with a 17069 manufacturer's specific code makes quite a difference. The generic code for this fault is P0685 and is relative to the  ECM Power Relay Control Circuit (See other codes below). From which  I can deduce that the Motronic ECM power supply relay itself  may be faulty, because of the 36-Open Circuit designator. However there are several possibilities. One possibility is that the solenoid winding is open circuit, and another is that its contacts doesn't close properly (open circuit), which is more likely. 

But there would also have been additional error codes, like 17072 or 17073. Considering either way, no rail voltage will reach the ECU, neither the injector coils, nor the injectors, etc, hence they won't function and the car would never start. So you need to prize-out the relay and do a physical check to make sure the contacts make or break as expected. The relay number is  J271 and will probably have the number 428 painted or stamped  on it. But before I explain how to do that, I want to raise a few points regarding the rest of your note. 

The clicking sound you hear, may or may not be the relay. If you said a single click I would agree that it's a relay, but since you said clicking, which implies several repeated clicks. It's most likely it's the starter solenoid that is chattering because their is insufficient voltage to keep it engaged, since you say it goes down to 8.5V under load. I'm inclined to favour this idea because it sounds like you battery is running down after 4 days and therefore not strong enough to drive the starter. But since you had that checked, try substituting another battery to make absolutely certain. 

The alternator could also be faulty and not charging the battery but I see you had that checked as well. Yet, it could imply that the diodes in the alternator are breaking down under load even though they function normal at idle. The battery voltage must be at least 11.5 volts constantly for everything to function as normal. Use your DMM and measure if there is any  resistance (ohms) between engine and body, there shouldn't be any. Also make sure you have a good connection  between the  negative battery terminal and the body. 

Regarding the amperage measurement, current is measured in series with the load. I don't think you should try to measure amps with your DMM because it may not be rated to measure more than 10 amps and may blow a fuse or damage its internals. Probably best to get a current clamp to measure current on cars. To return to the chattering, the starter could also have a intermittent power connection and could be the reason why it sometimes starts and sometimes not. Or the starter could be shorting to earth intermittently and draining the battery, hence the 8.5V. The best way to check this is to remove the starter and engergize it on a work bench to make certain it works the way it should. Before removing any control modules or relays from  the relay plate, make sure you disconnect the battery earth cable.

Relay J271 - Pin 85 and 86 are the solenoid terminal. Pin 85 is the 12V input whereas pin 86 is the solenoid earth. 
In the above image,  the only switch contact is between Pin 30 and Pin 87 which is normally open circuit.
When 12V is applied to 85  and 86, (normally happens when the ignition switch is turned  on) the relay 
should click and the power applied to pin 30 should exit on pin 87. If you hear the click but no voltage
 comes out  at pin 87, the relay internal contacts isn't making contact.
Try cleaning the contacts with fine sandpaper.

J271 varies from VW model to VW model, but once you have the relay out, check one of  its sides for the diagram of the pin-outs. It would look like the image on the bottom right.   The solenoid 12V supply will always be marked as 85, the negative always as 86, the normally open (N/O) contact as 87, or the normally closed (N/C) as 87a (if there is one). The pin marked 30 is always the switching voltage supply input. Notice that terminals of 87 and 30 are always larger than the other terminals because they carry a larger amount of current.  

Connect the relay solenoid to a battery with clip leads and measure the voltage at 87 and 87a, and verify that it switches over when you hear the relay click. Alternatively do a continuity test between pin 30 and 87, then again between 30 and 87a and make a note which one is open and which one is closed. Then connect power to the solenoid, pins 86 and 85 and verify that its continuity measurement switch over to the other pin. Unlike the image above, there may be even be more than 1 double pole double throw switch contacts on the relay depending on the model of your car. The Audi J271 is different to some VW's and has more terminals. It's also a good idea to check the relay socket wiring to or from the fuse box.  


P0685 - 17069   (ECM/PCM) Power Supply Relay - J271 - Circuit Open
P0686 - 17070  (ECM/PCM) Power Supply Relay - J271 - Short to Ground
P0687 - 17071   (ECM/PCM) Power Supply Relay - J271 - Signal to Positive

P0688 - 17072  (ECM/PCM) Power Supply Relay - J271 
Load Sensing Circuit - Open Circuit 

P0689 - 17073  (ECM/PCM) Power Supply Relay - J271 
Load Sensing Circuit - Short to Ground

P0690 - 17074  (ECM/PCM) Power Supply Relay - J271 
Load Sensing Circuit - Short to positive

P068A - (ECM/PCM) Power Relay Load Circuit - J271 - Opens Too Early  
P068B - ECM/PCM) Power Relay Load Circuit - J271 - De-activated Too Late

DSG MULTITRONIC TIPTRONIC

DSG MULTITRONIC TIPTRONIC

There is  a common saying that goes something like this, "You can call a dog my any other name, but its still a dog." So whether you  call your Volkwagen, Audi, Seat or Skoda's multitronic transmission a gearbox or call your Direct Select Gearbox a transmission, it is still the same DOG, even though it is spelt DSG. The 02E Direct Shift Gearbox (DSG) is known  as the S-tronic 02E twin-clutch gearbox in Audi circles, and this 02E VW, Audi, Seat, Skoda – Multitronic DSG / CVT Transmission has a fully fledged Electronic Controller (TCM / TCU) onboard-- internal. Because of this, virtually all automatics and semi-automatics, wheter S-Tronic, Mechatronic, Multitronic, Tiptronic,  Continuously Variable Transmission (CVT) or a Direct-Shift Gearbox (DSG),  seems to be extremely troublesome. In fact VW,  Audi, Seat, Skoda owners have so much transmission trouble that in VAG circles it is notoriously known as DOG common. transmission trouble vary from difficulty with the gear selector lever, to stripped gears, to a stretched CVT chain, to faulty solenoids, all of which can cause the transmission to enter emergency mod a.k.a limp-home mode and present you with a flashing P R N D S display or a permanently lit reverse image display.  

In certain cases some of these faults may be corrected by simply renewing the Gearbox oil, or even software update but the bulk of the trouble is caused by the aforementioned Transmission Control Module (TCM), which is also also known as the Gearbox ECU or the Transmission Control Unit (TCU). A faulty Transmission Control Module (TCM) can cause a number of  faults ranging from an intermittent fault that  progressively gets worse.  It can cause the gearbox not to go into gear or to automatically go into neutral or loose power, or stop working when it gets hot. At times the Transmission Control Module (TCM) may be faulty yet not turn on any warning lights and the only way forward, is to scan the TCM to locate the problem.

"DOG COMMON" DSG DIAGNOSTIC TROUBLE CODES.

18223 P1815 Pressure Control Solenoid 1 (N215) Short to B+
18227 P1819 Pressure Control Solenoid 2 (N216) Open / Short to Ground
18228 P1820 Pressure Control Solenoid 2 (N216) Short to B+
18231 P1823 Pressure Control Solenoid 3 (N217) Electrical malfunction
18232 P1824 Pressure Control Solenoid 3 (N217) Open / Short to Ground
18233 P1825 Pressure Control Solenoid 3 (N217) Short to B+
18236 P1828 Pressure Control Solenoid 4 (N218) Electrical malfunction
18237 P1829 Pressure Control Solenoid 4 (N218) Open / Short to Ground

18241 P1833 Pressure Control Solenoid 5 (N233) Electrical malfunction
18242 P1834 Pressure Control Solenoid 5 (N233) Open / Short to Ground
18243 P1835 Pressure Control Solenoid 5 (N233) Short to B+
18246 P1838 Pressure Control Solenoid 6 (N371) Electrical malfunction
18247 P1839 Pressure Control Solenoid 6 (N371) Open / Short to Ground
18248 P1840 Pressure Control Solenoid 6 (N371) Short to B+

18222 P1814 Pressure Control Valve 1  - (N215) Open / Short to Ground
18226 P1818 Pressure Control Valve 2  - (N216) Electric Error
18238 P1830 pressure control valve 4  - (N218) Short to Plus

17106 P0722 Gearbox Speed Sensor 1 G195 No Signal
18201 P1793 Gearbox Speed Sensor 2 G196 No Signal
17111 P0272 Rounds Count Signal From Engine ECU, No Signal
17090 P0706 F125 Drive Position Sensor Signal Implausible
17134 P0750 Control Valve 1/Solenoid Valve (N88) Function Disturbance
17137 P0753 Control Valve 1/Solenoid Valve (N88) Electric Error
17114 P0730 Gearshift-/ Transmission Surveillance Wrong Gear Ratio
19143 P2711 Unexpected / Implausible Mechanical Gear Disengagement

The 6-Speed Direct-Shift Transmission (DSG) with Mechatronic J743 shares the same construction of a manual transmission but has the operation of an automatic transmission and fitted into the New Beetle, Golf, Golf R32, the Touran, Audi and so many other models, especially matched to the 2.0L TDI and 2.0L TSI Engines. 

SOME DSG UNITS

02E 300 041 N
02E 300 041 R
02E 300 042 Q
02E 300 046 D
02E 300 046 F
02E 300 046 K
02E 300 146 D
02E 300 146 F

02E 325 025 AD
02E 325 025 AD Z01
02E 325 025 AD Z02
02E 325 025 AD Z03
02E 325 025 AD Z04
02E 325 025 AD Z05
02E 325 025 AD Z06
02E 325 025 AD Z07
02E 325 025 AD Z08
02E 325 025 AD Z09
02E 325 025 AD Z0A
02E 325 025 AD Z0B
02E 325 025 AD Z0C
02E 325 025 AD Z0D

02E 927 770 AD
02E 927 770 AE
02E 927 770 E
02E 927 770 AJ
02E 927 770 F
02E 927 770 G
02E 927 770 L
02E 927 770 M

02E 927 777 D
02E 927 777 OE
02E 927 777 OF
02E 927 777 OL
02E 927 777 OM

The cost of repairing  a DSG Gearbox ECU can easily set you back a good $1200.00 or more, and this  excludes  the cost of reprogramming (coding) the TCM, even though it is a fairly simple repair. The most common transmission problems are solenoids that get stuck in an open or closed position because  the transmission oil isn't replaced at the proper intervals, which then loses its viscosity and because of the heat, hardens between the valve body and the solenoid piston (plunger) causing it to seize.  When this happens the solenoid winding burns out or becomes high resistive. If the transmission oil is replaced as regular as it should, it will in fact lubricate the solenoid plunger (piston) and not get stuck. Problem is, the 7 litres of oil is also quite expensive but rather cost of the oil than an expensive TCM replacement and downtime of the vehicle.
The other problem is the engine heat and the gearbox heat and the transmission oil heat affects the wiring in the enclosed TCM, resulting in the ribbon cable becoming brittle which needs to be replaced when ever the TCM is serviced. The Gear selector switch also have several solenoids that could make you think that the transmission module is faulty even though its not. Its probably best to test all the solenoids before deciding to take out the gearbox.

EPC Q & A CONTINUED

EPC Q & A CONTINUED

It appears that more and more VAG drivers are experiencing Limp Mode with their VW, Audi , SKODA and SEAT vehicles and it appears that service agents are not as competent as expected. This urged me to present 3 more limp mode cases on a VW Beetle, VW Golf and a Golf TDI for the benefit of those with similar vehicles.

Question?

Hello my name is Mariiam Lopez. I have a 2002 VW beetle. I had been having problems with my car for more than a year. First started with the EPC LIGHT on, I had it on for a few weeks and it came and went, but then my car started to lose power while driving. I had to park and turn it off. I would wait a few minutes and then I started it again and the light went off . But then the EPC light stayed on and the speed didn't go up 10 miles (limp mode). I went to a mechanic and he said it was the throttle body. I had it changed. Two days the EPC LIGHT got on again. I took it again to another mechanic and he said it was the accelerator sensor. I change it and I even got the pedal. Next week got the EPC LIGHT on. It was driving regularly until it didn't want to turn on. I let my car rest for more than two months. I stared using it for a few weeks now and the EPC LIGHT goes on and off when I turn off. Now while driving in the freeway my car lose power and I have to park and let it rest for a few minutes and it drives fine but after a few minutes EPC LIGHT turns on. Now my car turns off in the middle on the freeway and all the lights on the dashboard are on. I park and turn on again but I have to accelerate in order to make my car work. Also the red oil light goes on and beeps when EPC light is on. My car has the same radio. Thanks

Answer!

Hola Mariam como estas? I so sorry to hear that you've had so much trouble with your VW Beetle and for such a long period of time. I can relate to what you are going through every time you need to go somewhere, especially at night when you have to drive a car that is completely unreliable. Considering that two mechanics, both of whom guessed that your throttle body and your accelerator sensors were faulty and that both parts were  replaced and your Beetle is still faulty, makes you saint with the patience of biblical Job. But your mechanics are not alone, so many VW service agents replace parts on Beetles and other VAG vehicles on a regular basis which often doesn't fix the problem, making car owners constantly despondent with VW and their "technical personel". At this point in time  I would be very hesitant to suggest that you replace any component without a diagnostic scan of your Beetle. It would have been great if you can get a copy of your Beetle's scan from one of your mechanics and upload it, so that I can  properly analyse it. Mind you, the data in group 60 - group 66 would  really be helpful to determine whether or not the adaptation was successful.  The EPC light problem can be caused by some many things and in your case its not your radio. So I suggest you check the fluid levels of your oil and coolant and make sure the coolant isn't leaking from reservoir bottle onto the wiring harness, if it does, the instrument panel is bound to malfunction. Also check that your fuel cap seals properly and check the vacuum hoses from the brake booster to the secondary air inlet valve and the hose to the combi valve. If this doesn't solve your problem, read through some of my other blog pages to get a better idea of what must be checked. I don't wish to scare you but Beetles especially MY2000 are well know for electrical problems and catching alight with the flames originating from underneath the firewall,  burning its way up the wiring harness, melting the fuse block on top of battery. So do take care.

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Question?

Hello my friend. I'm Charles Gunn and I have a VW golf mkv fsi 1.4 2005, which I bought in December of 2007. Since I bought her, she's been going into limp mode when I least expect her to, and have had this problem for the past three years. In my endeavours to fix it, I've tried so many garages, non of whom  could help. Worst of all a VW dealer charged me well over £1200, for replacing the wrong components, making me go back and forth to them, yet they never sorted out the problem. Furious... My VW golf goes into limp mode regardless of weather conditions and especially on long drives and on the motorways whenever I exceed 100kph. I found switching off the engine and letting it cool before staring helped but this was temporary because when it becomes hot, limp mode returnes. She frequently lost power when going up hill or on an incline to a bridge. I've done lots of internet  research and tried most forums but no luck. Thus far I've replaced the NOx sensor, MAF sensor, four coil packs and a fuel rail pressure sensor and an air filter. I spent over £1500 and still have a limp mode problem. Can you please help me? The fault that showed up on the scan is; 

1 Fault Found 
16575 - Fuel Pressure Sensor (G247): Implausible Signal 
P0191 - 008 - Implausible Signal - Intermittent 
Readiness: 0000 0000

Answer!

Hi Charley, I must commend you for your perseverance and for your gusto to kick limp mode's ass. Three years of limp mode is probably more than most people can bear. Anyway I see that you replaced a NOx sensor even though your Readiness is 0000 0000. A faulty NOx sensor would have interfered with your short term fuel trim, which would have resulted in a 0010 0000 readiness. A faulty MAF or air filter would also  have also interfered with your readiness which would have resulted in 0001 1000 reading. I'm so sorry to say that you replaced these items, because according to your readiness monitors they are not he cause of your troubles. The coils you replaced can cause limp mode but would also causes the engine to vibrate and idle poorly which would have also given you a P0300 (misfire) error code, so I think they were also replaced unnecessarily. The fact that you replaced the fuel rail pressure sensor says that your were definitely on the right track as pointed out by theP0191 fault, which may have been faulty hence sending intermittent signals to the ECU. However I am more inclined to think that your submersible fuel pump inside the tank is the culprit since it is responsible for creating the fuel pressure, which  is absolutely necessary to drive the injectors. But before you replace the pump, monitor the voltage supply to the pump since corrosion on the fuse in the fuse box that supplies the fuel pump voltage could cause a very similar symptoms.

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Question?

Hi, I need your advice  and please go easy on me because I'm a woman, who  knows very little about cars.  I have a Vw Golf GT TDI 2.0 with 81000 miles on the clock, which I bought about a month ago and it goes into limp home mode, whenever I get to about 70 mph and 3000rpm's but it comes right  when the engine is turned off and back on again. The local garage  ran a dianostics check and they suggested that I either put some diesel cleaner into my tank or use cleaner diesel as they think it's the turbo sensors that  gets clogged-up with soot! I've done some internet research and forums suggested I check the MAF.  So yesterday i drove the Golf untill it went into limp mode, then I switched off the engine and unplugged the MAF.  I could feel that the turbo wasn't working, not as responsive as it usually is. Anyway I drove upto 75 mph, when limp mode usually kicks in. Nothing happened and I increased my speed to 85mph and limp mode still didnt make an appearance. I stopped the Golf, switched off the engine  plugged MAF back in and sure enough limp mode kicked in at 75mph, do you think I need to change the MAF or could it be something else causing the problem?

Answer!

Hi there. It really would have been great if you had a diagnostic scan from which to work but since you don't have one, analysis is bound to be difficult and probably inaccurate. A MAF sensor can cause a limp mode home fault but it doesn't not mean it is faulty in your case. By disconnecting the MAF sensor the OBD System Component Monitor would immediately determine that the  mass airflow  sensor circuit voltage is outside an acceptable range. Thus One of two things could happen:-

1. The ECU will prevent the car from starting.
2. The engine will start but may trigger the malfunction indication lamp (MIL) and the car would also smoke profusely. Since the ECU cannot achieve the required stoichiometric ratio, it will trigger a DTC P1101 in memory. If the ECU supports "failure mode effects management" (FMEM) it will  default to a ‘safe’ mass airflow value, allowing the the vehicle to be driven to workshop for repair. Somehow I think you may not have unplugged the MAF but it is worth your while cleaning the MAF but be careful not to damage the wire inside.  Since  your car is Diesel I somehow doubt that is would be the MAF .

Question?

Nazeem Sterris. Hi.I have a polo 1.4 16v bby.problem is epc light stays on. It starts well.revs up well but has a slight miss fire when idling.after couple of minutes of idling it goes into a limp mode where revs go up to 1500rpm and pedal don't work. Pls help

Answer?

Hi Nazeeem. The slight miss you are describing is most likely the cause of your EPC problem. Sorry, I cannot pinpoint the problem for you because  you don't have a diagnostic scan attached, I'm guessing that the miss could be associated with your Ignition Coils, your Fuel Injectors,  or your Throttle Body, or your Fuel Pressure Regulator Valve or even your Wastegate Bypass Regulator Valve. You need to work through them systematically but first check that your fuel cap seals because if it doesnt, the EVAP pressure cannot stabilize  and can also trigger the EPC circuit.  

POWER STEERING FAILURE

POWER STEERING FAILURE 

STIFF STEERING / STEERING WHEEL STIFF

It was a perfect sunny day  with hardly any breeze, when my wife and I decided to go for a Sunday outing. We loaded the  VW Polo 2.0L Highline, with picnic umbrella, and packed a picnic basket filled with food and refreshments.  I mounted the bicycle holder on the tow-bar ball and attached our 2 bicycles, and off we went. But our joyous mood  was  abruptly interrupted about halfway to our destination when the Polo had  a sudden steering problem.  This is probably the worst thing that can happen to any unsuspecting driver whilst driving in a relaxed state. As I was entering into a long but sharp curve, my power steering kinda "froze for a second" .  I was steering with one hand — which is all it normally takes  — because the steering wheel is so light. But before I could respond to grip the steering with two hands, I also instinctively braked and with screeching tyres, I hit the pavement so hard that both front airbags popped.

The steering wheel had suddenly become hard to turn / stiff and tight /difficult to turn.  Kinda difficult to explain.  A stiff hard to turn steering wheel as if there is no power steering.  It was light to steer when suddenly it was hard to turn the steering wheel, because the steering wheel went stiff.  A stiff steering when turning. The steering wheel becomes stiff and hard to turn. I hope you know what I mean. Fortunately there wasn't a another car involved and even more fortunate nobody got injured except my pride. The first thing that went through my mind after calming the wife down and confirming that she was ok, was to determine the extent of the damage. 

As the airbags deflated I looking at the dashboard and saw all the light on the dashboard glowing. The yellow EPC light was on, the yellow steering wheel light (K161) was on, the ABS light was on, the red battery light was on, and the yellow brake pad light was on. The engine had switched off  and I realized the ignition was still on.  So I tried started the engine and it wouldn't take, I switch the ignition off and tried again, all the light went out and the car idled. On further inspection, I saw the rim that hit the curb was deformed and the tyre was flat. I figured I could just fit the spare and we would be on our way. As I reversed away from the pavement,  the steering wheel  was back to normal, it was light again.  After fitting the spare wheel, I  turned the steering wheel two full turns in either direction with one hand or rather my fingertips.  This was very odd, even peculiar, because the Polo just came back from its 100k service / cam belt replacement a short while ago. I'm certain if there was any problem with my steering wheel my machy would have told me but he said absolutely nothing. Anyway, so we eventually get home and as I turned into my driveway the steering goes hard/stiff/difficult to turn once again. As I drove forward the steering wheel returned to normal. So I popped the bonnet, checking for anything out of the ordinary. I rolled under the Polo, checked the steering control module, looked at the steering pump (V187), yet it all checked out fine. Out came VCDS and I scanned the Polo and found the battery connection to be intermittent. Look at the 18010/P1602 error below.

Chassis Type: 9N - VW Polo
Scan: 01,02,03,08,09,15,17,19,25,37,44,45,46,56,76
---------------------------------------------------
Address 01: Engine       Labels: None
Controller: 06A 906 032 PB
Component: 2.0l ME7.5.10       0305
Coding: 00071
Shop #: WSC 01120
AAVZZZ9NZ7UXXXXX     VWZ7Z0G52XXXXX
1 Faults Found:
18010 -  Power Supply Terminal 30: Voltage too Low
P1602 - 35-10 -   - - Intermittent
Readiness: 0000 0000
---------------------------------------------------
Address 15: Airbags
Control Module Part Number: 6Q0 909 601 F
Component and/or Version: 05 AIRBAG VW5  0010
Software Coding: 12341
Work Shop Code: WSC 31414
6 Faults Found:
00595 -  Crash Data Stored
35-00 -   -
01214 - Crash Data for Belt Tensioner Stored
35-00 - -
00588 - Airbag Igniter; Driver Side (N95)
32-00 - Resistance too High
00589 - Airbag Igniter 1; Passenger Side (N131)
29-10 - Short to Ground - Intermittent
00589 - Airbag Igniter 1; Passenger Side (N131)
32-10 - Resistance too High - Intermittent
01280 -  Airbag; Passenger Side; Disabled
35-00 -   -
---------------------------------------------------

Thereafter I decided I was going to take the Polo back on the road. So I reversed out of the driveway and suddenly the problem was back. The only thing I did was climb the 30 mm coping at the edge of the driveway so I drove back into the driveway and as the  back wheels hit the driveway copping the steering was fine once more. Since the steering pump (V187) actually stops working for the second or so, it had to be something to do with the power. So I pulled on every visible cable that goes into the wiring harness to the steering pump (V187). I even checked the enclosed fuses on top of the battery when I noticed that the negative battery terminal wasn't properly tightened.  As I tightened the nut I discovered the nut was stripped and wouldn't tighten any further. Then realized this had to be the problem. I scratched around in the garage, found a screw that would work, tightened the battery terminal and reversed out of the driveway and drove it back in a few times and the problem didn't reoccur. So I called my wife and asked her move the steering wheel to and fro with her hand while standing outside the Polo with her hand  through the open window. I loosened the battery terminal and disconnected the battery while the polo was idling. When it was disconnected my wife couldn't move the steering wheel and when I replace the terminal she could. So I was totally convinced that the intermittent battery contact caused intermittent power to the pump which is exactly what happened a second before I fit the pavement.  
So now I had to track down the cowboy who stripped by battery terminal nut because the  last time I took the battery out to replace my headlight bulbs I personally tightened it and am darn sure it wasn't stripped. This was roughly a week before it went for that major service. It just had to be one of the workshop guys that was responsible so like three days later I went to my VW /Audi machy's workshop to complain and demanded compensation for the damage to my car but got the saddest news. The same Sunday that my wife and I want for our picnic my VW/Audi machy was out biking and was killed in a head-on collision and died on the spot. 

Here are some VW, Audi power steering problems listed below, all of which seem to have a (G85) sensor issue.

Address 03: ABS Brakes
Controller: 7L0 907 379 G
Component: ESP ALLRAD MK25 0203
Coding: 0006402
Shop #: WSC 3141
00778 - Steering Angle Sensor (G85)
000 - -

Address 34: Level Control
Controller: 7L0 907 553 F
Component: LUFTFDR.-CDC- 3C3P1 3081
Coding: 0015521
Shop #: WSC 02631
00778 - Steering Angle Sensor (G85)
004 - No Signal/Communication

Address 03: ABS Brakes
Part No: 6Q0 907 379 M
Component: front H02 0001 ESP 5.7
Coding: 0000000
Shop #: WSC 00000 000 00000
00778 - Steering Angle Sensor (G85) 
005 - No or Incorrect Basic Setting / Adaptation

Address 44: Steering Assist
Part No: 1K1 909 144 J
Component: EPS_ZFLS Kl.5   D04 1606
Shop #: WSC 00000 000 00000
00778 - Steering Angle Sensor (G85)
000 - -

Address 03: ABS Brakes    
Part No: 1K0 907 379 K
Component: ESP FRONT MK60      0104
Coding: 0021121
00778 - Steering Angle Sensor (G85) 
005 - No or Incorrect Basic Setting / Adaptation

Address 44: Steering Assist Labels: 6Q0-423-156.lbl
Part No: 6R0 423 156 B
Component: LenkhilfeTRW V277
Coding: 11221
Shop #: WSC 06402
00778 - Steering Angle Sensor (G85) 
49-00 - No Communications

When I surfed the net, I discovered that several other VW owners experience similar problems. Here a dude who says:- "The dealership keeps giving my car back to me unfixed yet still replacing parts! The dangerous part of this is the steering locks up when the car dies and i'ts still moving. I am fearful of driving it and I haven't gotten anywhere with VW.  I am not alone and that it seems to be the same particular year and engine as mine in most owners replies.  I would like to help find a solution before any serious accidents happen or anyone is hurt. Thanks".

The Steering Angle Sensor (G85) is an opto coupler fitted in a collar under the steering wheel airbag. It sends sends the  steering wheel position to the Power Steering Control Module (J500) at the base of the steering column interfacing with the Electro-mechanical Power Steering Motor V187 all of which need power to operate properly. If the power disappears, the pump doesn't work and the steering goes stiff until the power is restored.


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VAG FUEL TRIM PROBLEMS

SHORT TERM FUEL TRIM ISSUES

Modern day OBD-II systems can be described as high-end electronic systems that "sort of" took the automotive industry by surprise. As such , there are so many motor mechanics that have not made the transition from technologies prevalent in older model cars to the technologies pervasive in newer model cars yet, and understandably some never will.  Several of these motor mechanics don't even own a scan tool and even fewer of them are able to interpret the DTCs and the results of a diagnostic scan. With the  result, that many VW owners took it upon themselves to become ODB-II savvy and even do their own automobile repairs. Many of whom have invested in low end scan tools like VAG COM, Actron, Nextech Carmen,  Foxwell, OBD Scan, Altar, etc, and others invested in high end scan tools like G-Scan, VCDS, Xtool, Launch, AutoHex, Autel and Auto Boss etc. Even though the VW service departments are equipt with the best diagnostic scan tools they tend to lack the technical personnel with the requisite expertise to understand them and effectively repair clients VW, Audi, SEAT and SKODA cars. Electronics has taken over the modern day car and being knowledgeable about electronics is key however not every car owner  is therefore not equipt to to analyse the diagnostic printout. As an example, lets take a look at the infamous VAG fuel trim problems list below. All of them very loudly shouts that the stoichiometric  ratio is off. Generic Short Term Fuel Trim (STFT) DTCs range from P0170- P0175 which are generic government required codes and Long Term Fuel Trim (LTFT) range from P1123-P1130, P1139-P1139,  P1151-P1152, P0166-P1167 and all are manufacturer specific.

SHORT TERM FUEL TRIM (STFT)

16554 - P0170 - Fuel Trim, Bank1 Malfunction
16555 - P0171 - Fuel Trim, Bank1 System too Lean
16556 - P0172 - Fuel Trim, Bank1 System too Rich
16557 - P0173 - Fuel Trim, Bank2 Malfunction
16558 - P0174 - Fuel Trim, Bank2 System too Lean
16559 - P0175 - Fuel Trim, Bank2 System too Rich

LONG TERM FUEL TRIM (LTFT)

17531 - P1123 - Long Term Fuel Trim Add.Air, Bank1 System too Rich
17532 - P1124 - Long Term Fuel Trim Add.Air, Bank1 System too Lean
17533 - P1125 - Long Term Fuel Trim Add.Air, Bank2 System too Rich
17534 - P1126 - Long Term Fuel Trim Add.Air, Bank2 System too Lean

17535 - P1127 - Long Term Fuel Trim mult, Bank1 System too Rich
17536 - P1128 - Long Term Fuel Trim mult, Bank1 System too Lean
17537 - P1129 - Long Term Fuel Trim mult, Bank2 System too Rich
17538 - P1130 - Long Term Fuel Trim mult, Bank2 System too Lean

17544 - P1136 - Long Term Fuel Trim Add.Fuel, Bank1 System too Lean
17545 - P1137 - Long Term Fuel Trim Add.Fuel, Bank2 System too Lean
17547 - P1139 - Long Term Fuel Trim Add.Fuel, Bank2 System too Rich

17559 - P1151 - Bank1, Long Term Fuel Trim, Range 1 Leanness Lower Limit Exceeded
17560 - P1152 - Bank1, Long Term Fuel Trim, Range 2 Leanness Lower Limit Exceeded

17573 - P1165 - Bank1, Long Term Fuel Trim, Range 1 Rich Limit Exceeded
17574 - P1166 - Bank1, Long Term Fuel Trim, Range 2 Rich Limit Exceeded

17582 - P1174 - Fuel Trim, Bank 1 Different injection times

THE DEFINITION OF A BANK

Before we continue, it is important to get certain definitions right. In 8 cylinder (W8) engines and 12 cylinder (W12) engines, 4 or 6 cylinders are staggered  aligned at a V-angle,  72 degrees in relation each other, thereby making the engine more compact.  Each staggered row of either 4 or 6 cylider has its own head,  which is called a "Bank",  hence Bank 1 and Bank 2. On the other hand VR6 engines cylinders are also staggered but has a single cylinder head, however the three left most side cylinders (odd numbers) are called "Bank 1" (passenger side left-hand drive) and the right most cylinders (even numbers) are called Bank 2. Four cylinder engines normally have 4 in-line cylinders but here as well, the odd cylinders are called Bank 1 and the even cylinders Bank 2 as can be seen in the "Chassic type: Skoda Fabia  1,2l/4V" below. But this configuration does apply to all 4 and 5 cylinders engines because in some engines all cylinders are referred to as bank 1. Looking at  the above P-Codes  P0170-P0175 it can clearly be seen that  P0107 refers to Bank 1 and is common to both  P0171 and P0172. And likewise P01703 refers to Bank 2 and is common to both  P01704 and P0175. This information allows us to determine which cylinder is bank is running rich or lean. Intermittent signals may be due to continuous STFT occurrences or the bad electrical connections at the o2 sensors. However, every time the engine is started the OBD-II system  does a self test on the O2 sensors,  and should the Check engine light not remain on, then the O2 sensor is probably not the culprit.

______________________________________________________________________

Chassis Type: 6N - VW Polo
16554 - Fuel Trim: Malfunction: Bank 1
P0170 - 35-10 - - - Intermittent

Chassis Type: 6N - VW Polo
16555 - Fuel Trim; Bank 1: System Too Lean
P0171 - 35-10 - - - Intermittent

Chassis Type: 6Y - Skoda Fabia
16555 - Fuel Trim: System Too Lean: Bank 1
P0171 - 35-10 - - - Intermittent

Chassis Type: 3B - VW Passat B5
16555 - Fuel Trim: System Too Lean: Bank 1
P0171 - 35-10 - - - Intermittent

Chassis Type: 9N - VW Polo
16555 - Fuel Trim; Bank 1
P0171 - 35-10 - System Too Lean - Intermittent

Chassis Type: Audi 3.2
16556 - Fuel Trim; Bank 1
P0172 - 35-10 - System Too Rich - Intermittent

Chassic type: Skoda Fabia  1,2l/4V 
16557 - Fuel Trim: Malfunction: Bank 2
P0173 - 35-10 - - - Intermittent

Chassis Type: 6N - VW Polo
16556 - Fuel Trim; Bank 1
P0172 - 35-10 - System Too Rich - Intermittent

Chassis Type: 3B - VW Passat B5
16556 - Fuel Trim; Bank 1
P0172 - 35-10 - System Too Rich - Intermittent

Chassis Type: 1J - VW G/J/B Mk4
16556 - Fuel Trim: System Too Rich: Bank 1
P0172 - 35-10 - - - Intermittent

Chassis Type: 9N - VW Polo
16556 - Fuel Trim: System Too Rich: Bank 1
P0172 - 35-10 - - - Intermittent

Chassis Type: 6N - VW Polo 
16556 - Fuel Trim; Bank 1
 P0172 - 35-10 - System Too Rich - Intermittent

Chassis Type: 8D - Audi A4 B5
16557 - Fuel Trim; Bank 2: system too lean
P0174 - System too Lean

Chassis Type: 4F0 - Audi A6 3.2L
16559 - Fuel Trim; Bank 2
P0175 - 007 - System Too Rich

Chassis Type: 4A - Audi 100/A6 C4
16559 - Fuel Trim: System Too Rich: Bank 2
P0175 - 35-00 - -
16556 - Fuel Trim: System Too Rich: Bank 1
P0172 - 35-10 - - - Intermittent
16557 - Fuel Trim: Malfunction: Bank 2
P0173 - 35-00 - -
16554 - Fuel Trim: Malfunction: Bank 1
P0170 - 35-10 - - - Intermittent

Chassis Type: 8D - Audi A4 B5
16554 - Fuel Trim; Bank 1: Malfunction
P0170 - 92-00 - Unknown Error Elaboration
16554 - Fuel Trim, Bank 1
P0173 - 92-00 - Unknown Error Elaboration
17658 - Fuel Level too Low

Audi A4 B5 96 a4 2.8l
16558 - P0174 - Fuel Trim, Bank 2
P0174  - System too Lean  -detecting lean fuel in exhaust
16555 -  Fuel Trim, Bank 1
P0171  - System too Lean -- detecting lean fuel in exhaust
16554   Malfunction
P0170 - 35-10 - - - reached maximum amount of fuel adjustment
16557 - Fuel Trim; Bank 2
P0173 - Malfunction

Fuel Trim: System Too Rich means / Rich Mixture implying too much fuel, not sufficient air
Fuel Trim: System Too Lean means / Lean Mixture, implying too much air, not sufficient fuel

Correct combustion relies on an air/fuel mixture of 14.7 to 1 ratio. Meaning 14.7 parts air to every 1 part of fuel, but if  the air ratio dips below 14.7 parts, then the mixture is called  "rich", whereas when the air exceeds 14.7 parts, then the mixture it is called  "lean".  To keep the engine running properly, the Engine Control Module measures the oxygen content in the exhaust emissions with the oxygen (O2) sensors in the exhaust system and makes adjustments to the mixture by injecting more or less fuel. The ECU is capable of keeping the STFT air/fuel mix within  specific parameters under normal conditions, and is based on input signals  from the Barometric Pressure Sensor and the Oxygen Sensor and will make minor adjustments to the air/fuel mixture. However when these adjustments it makes exceed a internally stored predetermined level, it sets  a fault code. When DTC P0171 and P0174 are triggered, the oxygen sensors are detecting too much oxygen in the exhaust fumes instructing the ECU to add more fuel in order to maintain a correct  air/fuel mixture.  But when DTC P0172 and P0173 are triggered the reverse is implemented. When DTC P0170 and P0173 are triggered the ECU is unable to compensate for the errors and uses an internally generate signal as compensation.  The main causes of STFT DTCs are due to leaking vacuum  hoses or a poorly functioning  Mass Air Flow Sensor sensing too little air or a faulty Barometric Pressure sensor or insufficient Fuel Pump pressure. Functionality of all these sensors can be checked by verifying there scan data before attempting to replace them. Cleaning the MAF wire with electro cleaner may help but take care not to damage it. Symptoms of STFT DTC may cause the EPC light to come on, make the car go into limp mode, stall, hesitate before acceleration, idle unevenly, backfire and refuse to idle. LTFT will be dealt with in future blog.

CHECK ENGINE LIGHT

CHECK ENGINE LIGHT

 VW BASHING

In my humble opinion I think VW manufactures pretty decent cars especially since  several of their models  won car of the year, a few years in a row. In fact VW Polo is probably the least troublesome VAG car and unfortunately the VW Jetta is the most troublesome. However not everyone is impressed with VW and from what goes around  at VW service departments about the flashing check engine light and especially coming from the mouths of VW owners,  borders on disgust and disappointment. Some of the things I've heard them say are:- Volkswagens Suck- and their service departments suck even more. They are an unorganized bunch of monkeys ... VW as a company - customer service is definitely not their priority. The check engine light is how they make money. The Worst customer service I have EVER received.  VW cars need no introduction but they do need constant attention. I will never buy Volkswagen again. As soon as my VW Golf gets out of the shop I'm trading it in for a Hyundai! Volkswagon cars are shit. I'm seriously interested in a "don't buy VW campaign". Never, ever buy a Volkswagen because VW service departments give Toyota cars as loaners. I really loved Jettas before, but now they SUCK. 

Volkswagen do not have an engine number, it an expire date. When I said I drive a VW, the mechanic said "what a shitty vehicle". I don't know how I will sell this disaster of a car! So don't sell it - just trade it in and get a non-VW. The time and effort to fight with corporate Volkswagen will get you no where. Their monkeys do what they are trained to do. Most VWs are lemons and the service people know it. VW quality and service is terrible - I will never buy another VW product.  VW service people are complete fools. Mostly my problems have been with idiot VW repair people, piss poor VW customer service, yep I agree a lot of service departments do suck. VW "wear and tear" - what a load of crap - more like cheaply made, more plastic than metal. The service people at VW are awful to deal with because they know VW sucks. My recent problems with bad service turned to NO service after calling VWoA. Customer service at VW sucks...they are programmed to say: "I'm sorry you are having issues with you vehicle" over and over. 

So, where does this leave avid VW fans like you and me? Do we jump on the VW bashing band wagon or do we take a stand? What I'd like to say in defence of VW, is that since the SAE mandated ODB-II for all makes of vehicles built after 1996  and even supplied a list of generic diagnostic Trouble Codes (DTCs), meaning codes relevant to all cars. Its only a matter of time before all modern day cars start misbehaving and frustrate their owners like some VWs frustrate some of their owners. Little do we know what is happening in the diagnostic and repair, misbehaving and frustration ranks of Honda, Mercedes Benz, Kia, Hyundai,  Opel, Ford, GWM, Renault, Mazda, Alfa Romeo, Bentley, Chrysler, Fiat, Nissan, Jaguar, Lexus, Jeep, Chery, Daewoo, Toyota, Mitsubishi, Peugot, Volvo, Tata, Citroen, Dodge, Proton, Suzuki, Geely, BMW, Isuzu, Porche, etc. Considering most mechanical service departments may not have the necessary electronic savvy diagnostic skilled technical personal, automotive problems are going to be on the rise and more expensive to repair than ever before because unskilled and untrained mechanics are bound to take "like forever" to find the faults by guessing and by trial and error. I personally know of a case where a car  was in for service and repair for 52 days in a single year because the "automotive technicians" could not locate the source of the trouble.

COMMON VW CHECK ENGINE LIGHT PROBLEMS

A typical problem with Jetta / Jetta GLI / Jetta GLI 2.0L T / Jetta LX 5 cyl (2010-2011) / VW  Passat, Beetle, Golf, Tiguan, Routan, Eos, GTI and the VW  Taureg is the Check Engine Light (CEL) aka (MIL-Malfunction Indicator Lamp) that flashes or blinks continually or stays on especially in cold weather which is normally caused by a faulty Check Engine Light sensor. But when the Check Engine Light  (CEL) aka (MIL- Malfunction Indicator Lamp) comes on and the whole car shudders and shakes in an almost uncontrollable manner, not only does it sound expensive but also feels expensive. Check Engine Light  (CEL) aka (MIL-Malfunction Indicator Lamp) is also associated with failure to start, noisy  cranking, backfires, stalling and shaking, rev hesitation, visible black emissions and even engine fires. These issues often flags a P300 (random misfire) which motor mechanics, sorry "automotive technicians" readily pass over as a random glitch, returning the car to the owner saying "no problem found". A glitch that is bound to reoccur whist driving on the inside lane during peak hour traffic, which could consequently leave  the driver stranded on the express way.  This supposedly random error is actually a tell tail sign uttered by one of the ignition coils ( N70, N127, N291, N292) or injectors (N30-N34). A failing Ignition Coil  or a failing Injector gives exactly the same symptoms, upto and including turning on the EPC light (Electronic Power Control), the Check Engine Light (CEL) aka (MIL-Malfunction Indicator Lamp), limits the power and sends the car into limp mode and flags the relevant Diagnostic Trouble Codes (DTCs). Injector DTCs are from P0200 to P0212 and P0261 to P0296. Whereas Ingiton coils DTCs are normally from P02300 to P02335. Unlike older cars that have one coil that could go faulty, which would stop the car in its tracks. Modern day Volkswagen cars, have one ignition coil for each spark plug, implying 4 times the possibility of failure on a 4 cylinder and 6 times  the possibility of failure on a 6 cylinder engine and more ignition coils for the spark plugs per cylinder engines.  If 1 ignition coil or 1 injector fails, the other coils continue to keeps on firing their individual spark plugs. Along with the functioning injectors  keep the engine running but unbalanced due to one cylinder not lagging behind-- because of a dead coil or injector. This shake is so bad that it makes driving the car virtually impossible.  Since, it is very unlikely that 2 coils or 2 injectors would fail at exactly the very same instant, a quick and easy repair method is to keep a new spare coil and injector in the tools box which could be replaced by the process of elimination until the problem is solved.

The other common Check Engine Light  (CEL) aka ( (MIL-Malfunction Indicator Lamp) culprit is the mass air flow (MAF) sensor (G70) which works in conjunction with the Oxygen (O2) sensor to provide the correct volume of air for  stoichiometric calculations.  The MAF is situated between the throttle body and the air filter pan and sends direct predicted air flow data to the ECU, while the oxygen sensor sends feedback data to the ECU so that it can  make the minor corrections to the predicted air mass. Mass Air Flow Sensors (G70) are mechanical devices and therefore prone to failure since their measuring elements tend to get worn overtime, flagging  P1144, P1145 or P1146 DTCs. Mass Air Flow Sensors can possibly cause a wide range of engine problems much like those caused by the ignition coils and injectors. It is therefore essential to download the Diagnostic Trouble code (DTC) memory to determine whether the ignition coils, the injectors or the Mass Air Flow Sensors is causing the problem.

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EPC Q & A

EPC Q & A

So many Audi, VW, SKODA and SEAT owner are having EPC light nightmares. Sending their vehicles for EPC repair which are often misdiagnosed, costly, ineffective and futile because most mechanical repair personal are not electronically trained hence have no idea of  digital logic and isolation procedures.  Modern cars are strewn with sensors and actuators, network buses, electronic control modules driven by software. To quote a line in Turks and Caicos which goes something like this "... everything changes. I used to be able to take a wrench and get under my car's bonnet and fix my car. Now you need a degree in electronics. Even easy things are difficult now." Replacing automotive components does not have to turn into a 'wild goose chase' where guess work is based on trial and error which now has become the order of the day.  That approach just scares everyone. Upload the diagnostic scan of your car now, so that I can analyse for you before you go ahead and buy expensive parts only to find out that the DTC was incorrectly interpreted.

Question?

I'm Lorraine from long beach. I don't know who you are but you are a God to me. I've been searching the web for months for specific and in-depth information on the "death light" (EPC) appearing on my '99 Volkswagen  Beetle. I have studied your entire blog and will now have a very interesting conversation with my German Car mechanic on how he can detect once and for all the problem. Already $1,000 in with no results. Thank you. I hope I don't have to sell the car just yet (to whom, I have no idea) throttle body replaced-twice so far-but hmm that Cam Bus section is interesting. My radio went into Safe Mode months ago and then spontaneously came back on (we do not have the code) so maybe we should check that path out as well. Again thank you.

Answer!

Hi Lorraine, since you don't say much about the specific problem that you are having other than the "death light" (EPC) appearing on my '99 Beetle, I really can't comment on it. However since it is EPC related, your problem has something to do with fuel delivery and engine torque electronics. Bear in mind that your fuel is under pressure from the tank to the injectors and that the ECU receives inputs from the various pressure sensors. If any of these pressures are below spec, it can trigger an EPC problem. For example, if your fuel cap does not seal properly the low fuel pressure sensor G410 will send a error signal to the ECU which can trigger an EPC fault. Likewise if the fuel regulator sensor cannot equilize the fuel pressure from the high-pressure fuel system it will trigger an EPC fault. Suppose If you were driving on an incline like an on-ramp to a bridge and didn't gear down sufficiently for you Beetle to swiftly climb with ease, the likely hood is that detonation would occur. If this happens, the knock sensors would inform the ECU which translate detonation as insufficient torque and trigger the EPC circuit - limp mode and EPC light. There are several other EPC possibilities but without a diagnostic scan it is difficult to pin point the problem.

Question?

Anonymous. I have a '07 Polo 1.4 16v BUD. I don't have any lights on the dash, but the engine seems really weak through mid revs and is using a bit too much fuel. When I hook up my OBDII there are no faults recorded but when i view the throttle position in real time it doesn't seem to open in a linear manner. As I press the pedal on the road, the throttle valve seems to open slower than the position of the pedal. eg; 50% pedal = 30% throttle position, 80% pedal = 35% throttle, 95% pedal = 40% throttle, 100% Pedal = 100% throttle. As you can see WOT does give WOT at the throttle body, but I don't generally drive with my foot planted on the floor. I am confused why it does this as you would expect the throttle body to open the same amount as the pedal, could it need alignment? I am loathed to take it to the VW dealer for fault diagno$i$ so if anyone has any ideas???? Thanks

Answer!

Hi there. Since you don't have  diagnostic scan its difficult to help you however, the mere fact that you don't have dash light makes it very obviously that you have electrical problems or wiring harness problems. And since your scan tool didn't find any DTCs, further proves that this is the case. The dashboard is normally directly connected to the OBD port in the driver's cockpit and since you have no dash lights you most likely have missing voltages on the OBD port which is most likely needed to perform a proper and correct diagnostic scan. Check your fuses on the terminal 30 line and the relay that supplies the terminal 15  supply line. Once you've exhausted everything else, as a last resort your dash control module could be faulty. Anyway, the acceleration peculiarity that you are describing probably has nothing to do with the dash electronics. Since you car has drive by wire, which is totally electronic (not throttle cable), torque is determined by the ECU which will open the throttle valve logarithmically based on its load and terrain, thus there is no physical correlation between the accelerator pedal and the throttle valve. So, no I don't think it needs alignment but seeing you have an OBD-II scanner, its quite simple for you to just redo the adaptation (described in a previous blog) and take consolation in the fact that you have eliminated it as a problem.

Question?

Hi I have a problem with EPC it came on since yesterday, am worried please help.

Answer!

My friend, you really not giving me much to work with here. But I suggest that read through my blogs pages related to EPC, torque, drive by wire, accelerator pedal sensors, knock sensors,  throttle adaptation, engine RPM sensor, etc. Perhaps if would shed some light on your EPC problem. Remember that EPC problems are related to what the car was doing at the time the light came on. for example, spirited driving / towing / start stop peak hour traffic, etc, Anyway the best way to find blog pages relating to your EPC problem , is to type your search word (EPC / drive by wire, etc) in the search box I provided in the top left hand corner on the first page of my site and click on the miniature magnifying glass to run the search. Happy searching.

Question?

Hi everyone, I would really appreciate some advice from you all. I have a 2002 (52) Ibiza 1.4 Sport (100bph), and have some issues with it. Background: Since day 1 it has occasionally thrown up an EPC warning light, followed by an engine electrics light. They would go away after a day and not return for several months. I had the logs read by a Seat dealer during a service and they said it had shown an intermittent Lambda filter error, and that it would cost £240+ to fit a new one. I passed. Over the last month, this has become an every day occurrence. The EPC light will come on seemingly as I just try to pull away from stationary. The car sometimes (half the time) notably stutters when this happens, then pulls away normally. If I restart the engine, most times the EPC light will go off, but the engine light will stay on. Then, more weirdly, the car has started occasionally stalling at random. No judder, no rough idling, I'll be slowing down towards a roundabout or into traffic, and whilst idling (coasting on the clutch) as I slow down, I'll notice the battery light come on, and the power drop out. Once, the battery light came on, but I was able to rev the engine up and it recovered - the battery light then went out. Mostly, I need to restart the engine though. I took it to a garage called Vee Ws for its annual service yesterday and asked them to look into it as well. They went with a cautious (on my finances) approach, and said they'd do the full service and that hopefully that on its own might rectify some of the issues. After the service, they said the logs showed some intermittent issues but nothing serious. They reset the onboard computer to its basic/default settings and said they hoped that would sort it. They also said they noticed the throttle body was pretty dirty (done 71,000 miles), and that if the service doesn't sort it, that they would try to clean that up and see if it did the job. Anyway, 10 minutes after I pulled away from the garage, the lights came back on and today the stalling re-occurred. I feel like this could turn into one of those 'wild goose chases' where its a case of trial and error, replacing different parts to see if it works. This scares me greatly! Has anyone experienced any similar symptoms, or would anyone recommend going to a proper Seat Dealership/Services team to take a look? I wonder if maybe they may be more likely to find the underlying fault? Having said that, I've always found Vee Ws in Bristolonia competent and most importantly, cost-effective. It may be possible to ask them to try and source used-parts while they try different 'fixes'.. Thanks for any advice, Jamie

Answer!

Hi Jamie,  the fact that your SEAT occasionally throws up an EPC warning light, as well as  the engine electrics light, says that your problem is more likely emission related, hence your intermittent Lambda error. Normally only torque and fuel related problems triggers the EPC light, meaning the engine light doesn't come on. Engine light only comes on with emission related issues.  Considering the age of your car it is possible that the Oxygen censor could be glazed over (end of life) or its wiring connector could be intermittent. The oxygen sensor is a feedback mechanism that instructs the ECU to increase or decrease the fuel supply hence shuddering. But this may not be definite. Without a diagnostic scan, I  am more inclined to say it could be your throttle body sensors not only because your service agent said it was dirty but because of the stalling and stutters on pull away. This seems like the throttle valve isn't providing an adequate air supply when its needed. However if they serviced your SEAT and did the adaptation as they said they did, then its unlikely the throttle body else adaptation would have failed, even though they said its dirty. So its more likely to be your accelerator pedal sensors. I mention this because  the car switches off when you decelerate, implying while your foot was on the accelerator it was OK but by taking your foot off the accelerator the condition changed and the ECU picked of this which could be due to 1 or both intermittent potentiometers. When you initially start the car  the ECU does a self-test by switching on all dashboard lights and if no problems are detected turns them all off. So when you start and the EPC light turns off, at that specific point in time there is no problem, but half way through acceleration while driving the problem is detected and the ECU switches he car off. Intermittent DTCs that do not reoccur during four driving cycles, are automatically deleted from the system which explains why the EPC light goes out after a day or so and doesn't show up months later. Lets have a diagnostic scan and I will have another crack at analyzing your problem.

DIAGNOSING EPC LIGHT PROBLEMS

DIAGNOSING EPC LIGHT PROBLEMS

VW Polo EPC light goes on and the car won't rev. Audi MIL and EPC light turn on and car goes into lip mode. SEAT suddenly has no acceleration yet has maximum of 1200 RPM. SKODA accelerator problem, won't rev. Audi EPC light on and transmission is locked in park.

Audi and VW crankshaft position sensors.

Question?

Hello mate...
My car was running really sweet when suddenly I'm having throttle issues! I was going to my girls house when all of a sudden, smack bang in the middle of the road, I have no acceleration. The car just cut the revs into idle and causing the EPC light on the dashboard to light up. I managed to get it off the road out of the traffic. Several attempts later to get her to rev up but  nope, absolutely nothing. So I phoned the towing service and the dude  checked under the bonnet to make sure everything was in place so he disconnected the battery for a while so it would reset the computer. It still wouldn't rev, so he hauled it onto the truck and brought it to my house. My neighbour Freddy has a VCDS which he plugged in and these fault codes showed up. I'm desperately in need of help because I have no idea how  to  solve this problem?

Chassis Type: 6K - Seat Ibiza/Cordoba
Scan: 01 02 03 08 15 17 25 45 56
Mileage: 97850km/60801miles
-------------------------------------------------------------------------------
Address 01: Engine

Part No: 6K0 906 032
Component: 1.8L R4/20VT SEA 0002
Coding: 11500
Shop #: WSC 78904

5 Faults Found:

18047 - Accelerator Position Sensor 1/2 (G79/G185): Implausible Signal
P1639 - 35-00 - -
18039 - Accelerator Position Sensor (G79): Signal too High
P1631 - 35-00 - -
18042 - Accelerator Position Sensor 2 (G185): Signal too High
P1634 - 35-00 - -
17950 - Angle Sensor 1 for Throttle Actuator (G187): Implausible Signal
P1542 - 35-10 - - - Intermittent
17581 - Angle Sensor 2 for Throttle Actuator (G188) Signal too High
P1173 - 35-10 - - - Intermittent

Answer!

Hay George.This is quite interesting that both your accelerator potentiometers and both your throttle body potentiometers are acting up at the same time. Normally I would say that your accelerator pedal needs to be replaced if only G79/G185 flags repeated DTCs. Alternatively say that your throttle body needs  cleaning and adaptation if G187/G188 flags repeated DTCs. But this is certainly not the case though both these circuits are notorious for "No Throttle Response", limp mode and turning on the EPC light.  However to me it looks more like the voltage supply line to both devices is acting up, that it's intermittent.  Since the throttle and the accelerator are each connected directly to the same control module (ECU) I'm tempted to say that the ECU plug is probably loose or corroded or the fuse holder that supplies the ECU with terminal 30 (12V unswitched) and the relay that supplies terminal  15 (12V switched) needs to be checked for proper contact and corrosion. What I am willing to say is that you have a wiring harness problem, so check continuity between the ECU and the accelerator pedal 6 pin plug and the ECU and the Throttle body 6 pin plug. Make certain to do adaptation afterwards and check throttle valve control in group  060“ (G187/G188),  and especially 62 (G187/G188 & G79/G185), and 63 (Kick-down) and if you have a cruise control group 66 as well.

Question?

I'm Renshaw and I have an Audi A4 1.8T. When I started my car from cold, the EPC light came on and the engine just stalled. Made a couple more attempts to start but engine just cranks and  wouldn't start. After a while I tried  again and it started just fine and it drove fine. The following day  I couldn't start the engine again. So like before I waited a while and it started fine and I drove all week without any EPC problems, until this morning while standing in peak hour traffic my car just died.  After a few tries the car finally started but while I was driving both the EPC and the MIL (check engine light) came on, the engine lost power and was idling at 1200 RPM. This happened a few time over the past month and I'm really loosing my patient with my Audi A4.  So when it happened again I limped to the service agents  who got the 2 DTC errors:  P0321 Ignition/Distributor Engine Speed Input Circuit Range/Performance and P0322 Ignition/Distributor Engine Speed Input Circuit No Signal, but they could get the car to switch off like it did with me. Something like the toothache goes away when you get to the dentist. Anyway, I've search the Internet forums for a  EPC problem similar to mine but found nothing. I still don't have any idea what's going on. Can you please help me and I would be very appreciative and thank you.

Answer!

Hi Renshaw, thanks for your question. The problem you describing is fairly common on Audi which normally flags any or all of the following DTCs - P0320, P0321, P0322 and  P0323  at the same time. This is undoubtedly or rather more often than not caused by your Engine Speed (RPM) sensor signal (crankshaft sensor) that is out of phase. Bear in mind that your car has a DIS and not a mechanical distributor which is normally driven by a gear on the camshaft. This implies that your camshaft / crankshaft have embedded  magnets that energizes  a hall sensor (crankshaft sensor) or an inductive sensor mounted on the cylinder block which  measures crankshaft speed (interval), that provides the engine speed signal to the ECU. It also doubles-up as the signal that determines the time and duration of the ignition (spark) as well as injector timing. Depending on the model, the crankshaft sensor is next to the oil filter. Crankshaft position sensor (G28) failure is also common on the new VW Polo the new Jetta. 

NB!
If you need help with your EPC problem or an explanation of your diagnostic scan and willing to share the findings with fellow Vag owners, feel free to link to this post and upload  your question and a scan of your car. Not every problem can be dealt since there are a fair amount of overlap / common problems, but I will try my very best to answer as many as possible.