Thursday, October 1, 2015


18020 - Engine Control Module Incorrectly Coded

The VW Polo 9N manufactured between 2002 and 2010 is a real fun car and is available in several formats. Meaning either Gasoline or Diesel, or hatch back GTI or sedan as in trendline, confortline or highline. Each of these  fitted with either a 1.2L, 1.4L, 1.6L, 1.8L, 1.9L or 2.0L engine. As such their Electronic Control Unit (ECU) / Electronic Diesel Controller (EDC) differs quite a bit since they are matched to their respective engines which also varies substantially. Amongst which are the ATD, AMF, AVY, AWY, AZQ, BAH, BBX, BBY, BBZ, BMD, BMS, BMT,  BNV, BNM, divided into 3 cylinder and 4 cylinder engines. These engines have  6 & 12 valves for 3 cylinder engines, and 8 and 16 valves for the 4 cylinders engines. FSI = Fuel Stratified Injection. Often times when an engine is replaced, the engine cranks but just wont start. Scanning the ECU results in a 18020 DTC - Engine Control Module Incorrectly Coded. If the engine does not originate from exactly the same model, the following list of codes aught to help to recode the ECU to the correct type.

VW Polo 9N ECU Coding

01: ECM VW Polo 9N BBY 036 906 034 DD MARELLI 4MV 4448 00031
01: ECM VW Polo 9N BKY 036 906 034 GQ MARELLI 4TV 6280 00031
01: ECM VW Polo 9N BBY 036 906 034 HL MARELLI 4MV 5511 00031
01: ECM VW Polo 9N BBY 036 906 034 DD MARELLI 4MV 4448 00071

01: ECM VW Polo 9N BKY 036 906 034 KA MARELLI 4TV G 7448 00071
01: ECM VW Polo 9N BKY 036 906 034 JC MARELLI 4TV G 6549 00031

01: ECM VW Polo 9N AMF 045 906 019 -C 1.4l R3 EDC 0200SG 1479 00000 
01: ECM VW Polo 9N BNM 045 906 019 BP 1.4l R3 EDC G000SG 8395 00002
01: ECM VW Polo 9N AMF 045 906 019 BF 1.4l R3 EDC 0000SG 5179 00005
01: ECM VW Polo 9N BNV 045 906 019 CA 1.4l R3 EDC G000SG 7537 00005
01: ECM VW Polo 9N ATD 038 906 019 JK 1.9l R4 EDC 0000SG 1558 00005
01: ECM VW Polo 9N ATD 038 906 019 LB 1.9l R4 EDC G000SG 5101 00005

01: ECM VW Polo 9N AVY 036 906 033 D 1.6l/4V SIMOS3 00HS3512 00031
01: ECM VW Polo 9N BMD 03D 906 033 F 1.2l/2V SIMOS3 00HS2509 00031
01: ECM VW Polo 9N AWY 03D 906 032 C 1.2l/2V SIMOS3 00HS2501 00031
01: ECM VW Polo 9N AZQ 03E 906 033 L 1.2l/4V SIMOS3 00HS4726 00071

01: ECM VW Polo 9N BNM 045 906 019 BP 1,4l R3 EDC G000SG 8395 00002
01: ECM VW Polo 9N BMT 03G 906 013 R4 1.9L EDC G000SG 0622 000071
01: ECM VW Polo 9N BMS 045 906 013 R3 1.4L EDC G000SG 9554 0003071

01: ECM VW Polo 9N BAH 03C 906 057 AK 1.6l BOSCH ME7.5.20 0707 0000075
01: ECM VW Polo 9N BBX 06A 906 032 PB 2.0l BOSCH ME7.5.10 0305 00071

1.2 L 3 cylinder  6valve petrol,  55 HorsePower 40 killoWatt
1.2 L 3 cylinder 12valve petrol,  65 HorsePower 47 killoWatt
1.4 L 4 cylinder 16valve petrol,  75 HorsePower 55 killoWatt
1.4 L 4 cylinder 16valve petrol,  86 HorsePower 62 killoWatt
1.4 L 4 cylinder 16valve petrol, 100 HorsePower 74 killoWatt
1.6 L 4 cylinder  8valve petrol, 101 HorsePower 74 killoWatt
2.0 L 4 cylinder  8valve petrol, 115 HorsePower 85 killoWatt

1.4 L 3 cylinder TDI,  75 HorsePower 55 killoWatt
1.9 L 4 cylinder SDI,  64 HorsePower 47 killoWatt
1.9 L 4 cylinder TDI, 100 HorsePower 74 killoWatt
1.9 L 4 cylinder TDI, 130 HorsePower 96 killoWatt

Saturday, September 19, 2015



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. 

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. 

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 

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

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 

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.

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? 

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.

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.

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.   

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.

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 

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

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?

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.

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.  

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.

Friday, September 18, 2015


17069 - P0685 ERROR

Electrical problems seems to stymie everyone, but repairing an electrical fault can be fairy simple if traced logically. Relays are just remote switches. Audi, Volkswagen, Seat and Skoda relays can give a fair amount of trouble because its push-in 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.


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.



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, its most likely its 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.

J271 varies from model to model, but once you have the relay out, check one of  its sides for the diagram of the pin outs.  The solenoid 12V supply will always be marked as 85, the negative always as 86, the normally open (N/O) contact as 87, the normally closed (N/C) as 87a and the pin marked 30 is always the switching voltage supply. Notice that terminals of 87 and 30 are always larger than the other terminals. Connect the relay solenoid to a battery with clip leads and measure the voltage at 87 and 87a, and that it changes over when you hear the relay click. Alternatively do a continuity test between pin 30 and 87, then again between 30 and 87a. Then connect power to the solenoid and the continuity measurement should 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.

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

Wednesday, September 16, 2015



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.


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. 


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.

Wednesday, August 19, 2015



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.


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


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.



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


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.



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?


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 .


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


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.  

Tuesday, August 4, 2015




It was a perfect sunny day  with hardly any breeze when my wife and I decided to go for a Sunday outing. So we loaded the  VW Polo 2.0L Highline. With picnic umbrella packed and picnic basket filled with food and refreshments in the boot, I mounted the bicycle holder on the tow-bar ball and attached our 2 bicycles, and off we went. But our joy and contentment was very abruptly interrupted approximately halfway to our destination. This is probably the worst thing that can happen to any unsuspecting driver whilst driving in a very relaxed state. As I was going around a long but sharp curve my power steering kinda "froze for a second" and since I was steering with one hand, which is all it normally takes because the steering wheel is so light. But before I could respond with two hands, I instinctively braked and with screeching tyres, I hit the pavement so hard that both front airbags popped. The steering wheel had suddenly gone hard to turn / stiff and tight /difficult to turn.  Kinda difficult to explain.  A stiff hard steering wheel,  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. I first thing that went through my mind after calming the wife down and confirming that she was ok, was 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 and I realized the ignition was still on.  So I tried started the engine and it wouldn't take, 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, and very peculiarly the steering wheel  was back to normal. After fitting the spare wheel, I could once again turn the steering wheel two full turns in either direction with one hand. This was very odd, yet funny enough, 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 turn into the 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
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 then 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 with 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 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 revered out of the driveway and back in and out and in and out and in and it didn't happen again. 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 terminal and disconnected the battery while the polo was idling. when it was disconnected my wife could move the steering wheel and when I replace the terminal she couldn't. So I was totally convinced that the intermittent battery contact caused intermittent power to he pump which is exactly what happened a second before I fit the pavement.  

So now I have 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 an am darn sure it wasn't stripped which 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 demand 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 got killed in a head-on collision and died on the spot. Here are some 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  which sends a 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. 

steering wheel stiff, steering wheel stiff hard, Steering wheel hard to turn, steering wheel becomes stiff and hard to turn,  steering is very tuff and its hard to turn, Steering stiff and hard to turn, Stiff Steering,  stiff steering when turning, stiff hard steering, stiff hard steering wheel stiff and tight, hard to turn the steering wheel, hard to turn your steering wheel,

Monday, August 3, 2015



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.


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


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


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.