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.

CEL, check engine light, check engine light is flashing, flashing check engine light, check engine light is on, check engine light blinking, check engine light blinking car shaking, blinking check engine light,

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
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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.

EPC HELP

EPC HELP Q & A

VW Beetle EPC problems. Audi EPC light, Audi Q7, Audi TT, car trouble, DTC, drive by wire, DTC memory, EPC, EPC dashboard light, EPC faults, EPC problem, accelerator pedal adaptation, Audi EPC Light problem, Audi Q7, audi TT, car trouble, crankshaft position sensor, drive by wire, dtc, DTC memory, EPC, EPC dashboard light, EPC faults, EPC problem, high pressure fuel pump, Limp Mode, throttle body, VW Beetle, wiring harness, O2 sensor,

Question?

My name is Lilian. I bought a 2001 Volkswagen Beetle a few months back. Now it loses power whenever that EPC light and check engine light switches on. Lately it happens more  often, so I switch it off and after a while start it again and it drives ok for only a few miles. I just cant go on like this, its upsetting to the point that I can cry. The VW Beetle club members say its the throttle body, so my friend replaced it for me.  It was really expensive from the agents so a got a used one from the junk yard. It fixed the problem, or rather so I thought because after about 200 miles the problem is starting again. Now I feel helpless. Pleeeez help me. Pleez Pleeez Pleez!

Answer!

Hi Lil sorry to hear about your troubles. As much as I would like to help you, you gave me way too little information to steer you in the right direction. A diagnostic scan of the VW would have really been helpful but since you don't have one, fixing it is going to mere guess work. EPC faults, can be solved by a process of elimination and since you replaced the throttle body and it lasted for 200 miles, without a problem, it is very likely that it was the throttle body that was faulty but the question is, did your friend do the adaptation so that the ECU can properly interface and control it? Sounds like this is your problem. You need to take it to a diagnostics equipt workshop to have the throttle body adaptation reset. I'm almost certain that would solve your problem.

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Question?

Me Zoe, I got Vw beetle, make power loss and make  EPC dashboard light on. I read  VW forum say was cause by brake light switch. I take my mechanic, he  say no fix, take  VW agents they recall VW Beetles with brake light switch problem. Me very lucky, VW agent replace it free but EPC problem no fix and now more worse. Happen every day. You me help. I you kiss.

 Answer!

Hello Zoe thank you, I am flattered that you want to kiss me. I have to tell you though, that the brake light switch has little to do with the EPC problem you are experiencing. The brake light normally has an influence on speedo-cruise and has nothing to do with EPC faults which are rather confined to the non-emission related components involved with fuel delivery and torque delivery. The variables are just too many to even guess what it could be. It could be one of many things that could be causing your problem. Even something as minor as a bit of dirt restraining your throttle control butterfly could cause a EPC problem.  Right now you problem could be anything from the crankshaft position sensor to the accelerator pedal position sensor. From your throttle body to the electrical connections, from your high pressure fuel pump to the ECU. I would suggest you have a  scan done then send it to me, perhaps we can try once again to define your EPC problem. I hope you understand my explanation. Cheers Zoe.

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Question?

Hola mi amigo, tengo un problema en el polo de mi mujer, y es que se queda al arrancarlo por la mañana del garaje o cuando esta una tarde entera como hoy en la calle que ya hace freskito, como si no subiese de revoluciones,como muy flojo, si le aceleras lo calas, o aveces hace pequeñas detonaciones por el escape, esto le dura unos 20 segundos y ya se espavila. Es un polo 1.4i 80cv, tiene 20milkm, y no ha tenido otro fallo. Posibilidades? 1º Yo creo que puede ser sensor de temperatura de inyeccion, aunque me funcione bien la abuja que mide la temperatura del agua?. 2º bobina? No se que mas podria ser, en dias normales, o si lo arrancas despues de 3 horas o 10 minutos ya va perfecto. Le meti el VAGCOM y no me dio ningun tipo de error. Espero vuestras respuestas

Answer!

Hola a ti. Primero quiero  decir, hablo espanol un poquito pero voy a probar ayudar. Sin error del VAGCOM es mas dificil decir. Apuesto a que es problema de encendido pero dudo es la bobina si le dura de problema porque es solo 20 segundos.  Posiblemente son los bujias o la RON de gasolina no es correcto o tienes agua en la gasolina. Pequeñas detonaciones por el escape no es normal especialmente baja 20milkm. ¿qué pasa con su recien garantía?

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Question?

Hello there, I hope you can shed some light on my problem, I'm having a mini crises with my Seat 1.8L Toledo. The EPC light came on yesterday, but when I turned the engine off and restarted, the EPC light went off and everything was fine until this morning. On my way to work  the car had a jerky/shudder and at that very moment the TC and EPC light came on and I lost power so that it would only rev to  2500 rpm. As a result I limped home them  I plugged in my VAGCOM. Very surprisingly there were no faults. So I decided to take the Toledo back on the road but when I turned on the ignition, the EPC/EM/TC lights came on. So once again I plugged  in my VAGCOM and the DTCs listed below was present. So I cleaned the Throttle Body and  checked the Throttle Body on group 060 and the adaptation field was showing 'ERROR'. What do I do now because I'm totally stuffed and need  a quick fix. Any light you can shed on this problem would be much appreciated.

VAGCOM: Chassis Type: 1M - Seat Leon/Toledo

Scan: 01 02 03 08 15 17 19 22 35 36 37 46 56

VIN: VSSZZZ1MZ3R1XXXXX Mileage: 164400km-102153miles

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Address 01: Engine Labels: 06A-906-032-AJQ.lbl

Part No: 06A 906 032 MJ

Component: 1.8L R4/5VT 01 0003 

Coding: 11510

Shop #: WSC 80179 

VSSZZZ1MZ3R1XXXXX SEZ7Z0C2XXXXX

4 Faults Found:

17967 - Throttle Body (J338): Fault in basic settings 

P1559 - 35-10 - - - Intermittent

17987 - Throttle Actuator (J338): Adaptation Not Started 

P1579 - 35-00 - - 

17579 - Angle Sensor 2 for Throttle Actuator (G188) Implausible Signal 

P1171 - 35-10 - - - Intermittent

17951 - Angle Sensor 1 for Throttle Actuator (G187): Signal too Small 

P1543 - 35-00 - - 

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Answer!

Hi Wayne, I'm glad to see that you uploaded your scan. Since the rest of your electronic modules have "No fault code found" beneath them, it essentially means that they are all OK. And seeing that you own a VAGCOM, I take it for granted that you may have had prior DTC which you erased. Erasing DTCs are OK but bear in mind that you also erase all values learnt by the ECU associated with your driving style including adaptation values.  The throttle body therefore needs to be re-adapted every time codes are cleared or control module  or battery power is disconnected. As the automatic adaptation software procedure runs, the control module learns the full range of throttle positions. So from what I can see above, the Idle Speed Control Throttle Position cannot be determined which could mean adaption needs to be done, or that the potentiometers in the throttle body may be near end of life. Overtime the slider wears through the carbon track so it makes intermittent contact and stymies the ECU. But before we condemn the throttle body, I need you to disconnect your battery at the earth terminal so that you can hard reset all the electronic modules. Make certain that the ignition is off  then reconnect the battery. Redo a scan and if all goes well, you will once again see your original 4 faults and 1  additional fault that looks something like "Supply Voltage Terminal 30: Signal Outside Specifications - attery/Generator supply faulty". This is absolutely normal because the ECU detected that the battery was disconnected. Plug in VAGCOM switch on the ignition but do not start the engine. Select VAGCOM 04-Basic Settings - which displays the Measuring Value Block screen. Select Measuring Value Block 060 (or 98) which displays the Basic Setting Value Block screen.  Channel 4 will display the word“Running” and other channels will display  the state of the throttle valve angle sensors but will change as the throttle is actuated by the ECM.  Please do not touch the throttle pedal nor turn  ignition key off during the adaptation because the throttle body adaptation relearn process is essential and may prevent the engine from starting if interrupted. If the adaptation was successful, Channel 4 will have changed from “Running” to “OK”. Display 3 would read "idle" and 1 & 2 display voltages levels, normally less than 5 Volts.  Logout, turn the ignition key off and wait about 1 minute seconds, to ensure that adaptation settings are saved then start the car. If however, it still shows "error" inspect the throttle body actuator connector contacts for damage or corrosion and make certain its contacts are secure then try to set adaptation again. If it still shows "error" clean the throttle body and check for wiring harness between the throttle body and the control module. Retry adaptation once again. As a last resort replace the throttle body because the potentiometers cannot be replaced as a separate item nor is it available for sale as a separate item. I hope this helps.

INTERNAL CONTROL MODULE MEMORY ERROR

INTERNAL CONTROL MODULE MEMORY ERROR

DTC error 65535 (Internal Control Module Memory Error) suggests a problem was caused  within the said module. However, Electronic Control Modules are generally fairly robust and are designed with a MTBF of 1 million hours. My experience with electronic repairs over the past 30 years does not confirm this since I have had tons of electronic components failing during this time that was'nt expected to fail for at least another 10 years. Be that as it may, an Internal Control Module Memory Error may not even be caused by the module, so it should be the last component to suspect and replace because they are normally not cheap. Firstly check the battery Supply Voltage  and verify that it is constantly about 12V or higher. Also make sure that the alternator is charging, since a faulty alternator can lead to a slowly discharging battery not able to supply the minimum voltage required by the module that is flagging the  65535. Next check to wiring harness to and from the "faulty" Control Module. Make certain that the module has a ground connection (earth). If  VCDS displays an unexpected result or displays that the controller refused the command, it is most likely due to the wiring. Under intermittent wiring conditions it is generally difficult ifnot possible  to clear a  65535 (00-10) or (35-00) or (35-10) or (37-10). Wiring harness and its connectors are prone to corrosion due to condensation especially in cold weather. If needs be, unplug the connector and clean them and if possible check the physical contact with an ohm meter (but disconnect the battery first). Any Internal Control Module Memory Error associated with the Power steering  and ABS are critical and should be attended to immediately. Internal Control Module Memory Error associated with Airbags should be treated with caution since interrogation of the airbag with a scan tool could inadvertently trigger the airbag or turn on the airbag light which can only be switched off by replacing the airbag module. As can be seen below, virtually every electronic module can be a victim of 65535 - Internal Control Module Memory Error and as far as I am concerned, it most unlikely electronic design and quality control  will permit such modules to be installed in production units. The lateral acceleration sensor tend to cause an 65535 airbag error, the vacuum hose inside the ECU taking pressure to the barometric sensor tends to cause a 65535 error in Jetta's, barometric sensor itself tends to cause 65535 in Skodas.  As a last resort try replacing the module concerned.

Address 01: Engine
Chassis Type: 17 - VW Golf Citi
Part No: 6KS 906 258 k
Component: 1.4 MP9.0 26ZA0003
Shop #: 2227355880
65535 - Internal Control Module Memory Error

Address 02: Auto Trans
Chassis Type: 9M - VW Jetta IV
Control Module Part Number: 01M 927 733 KT
Component: AG4 Getriebe 01M 4891
Software Coding: 00000
Work Shop Code: WSC 00000
65535 - Internal Control Module Memory Error

Address 03: ABS Brakes
Chassis Type: 6Y - Skoda Fabia I
Part No: 6Q0 907 379 D
Component: ABS/ASR 5.7 FRONT V00
Coding: 00124
Shop #: WSC 13765
65535 - Internal Control Module Memory Error 

Address 03: ABS Brakes
Chassis Type: 1J - VW G/J/B Mk4
Part No: 1J0 907 379 AB
Component: ESP 20 CAN V005
Coding: 00214
Shop #: WSC 31414
65535 - Internal Control Module Memory Error

Address 03: ABS Brakes
Part No: 1C0 907 379
Component: ESP 20 CAN V005
Coding: 18945
Shop #: WSC 01317
65535 - Internal Control Module Memory Error

Address 03: ABS Brakes
Chassis Type: 6Y - Skoda Fabia
Controller: 6Q0 907 379 G
Component: ABS 5.7 FRONT V20
Coding: 00044
Shop #: WSC 13765
65535 - Internal Control Module Memory Error

Address 08:
Chassis Type: 6Y - Skoda Fabia
Controller: 6Y0 820 045
Component: Klimaanlage X0740
65535 - Internal Control Module Memory Error

Address 08:    
Chassis Type: 6Y - Skoda Fabia
Controller: 5J0 820 045
Component: Klimaanlage  X0850
65535 - Internal Control Module Memory Error

Address 08: Auto HVAC
Chassis Type: 6L - Seat Ibiza/Cordoba
Part No: 6L0 820 045 C
Component: Klimaanlage X00.8
65535 - Internal Control Module Memory Error

Address 08: Auto HVAC
Part No: 5J0 820 045
Chassis Type: Skoda Fabia 2
Component: Klimaanlage X0850
65535 - Internal Control Module Memory Error

Address 15: Airbags
Chassis Type: 9N - VW Polo
Part No: 1C0 909 605 K
Component: 18 AIRBAG VW51 0P 0010
Coding: 12600
Shop #: WSC 00788
65535 - Internal Control Module Memory Error

Address 15: Airbags
Chassis Type: 9N - VW Polo
Part No: 6Q0 909 601 F
Component: 05 AIRBAG VW5 0010
Coding: 12341
Shop #: WSC 31414
65535 - Internal Control Module Memory Error

Address 15: Airbags
Chassis Type: 6L - Seat Ibiza/Cordoba
Part No: 6Q0 909 601 F
Component: 01 AIRBAG VW5 0010
Coding: 12337
Shop #: WSC 06441
65535 - Internal Control Module Memory Error

Address 17: Instruments
Chassis Type: 8E - Audi A4 B6/B7
Part No: 8E0 920 900 HX
Component: KOMBI+WEGFAHRS. RB4 D27
Coding: 00142
Shop #: WSC 19411
65535 - Internal Control Module Memory Error

Address 37: Navigation
Part No: 3B0 919 887 D
Component: Navigation  BNO 0201
65535 - Internal Control Module Memory Error

Address 45: Inter. Monitor
Chassis Type: 6N -  VW Polo
Part No: 6N0 951 171
Component: Innenraumueberw. 0002
65535 - Internal Control Module Memory Error

Address 56: Radio
Part No: 1C0 035 157 C
Component: Radio DE2 0004
Coding: 00401
Shop #: WSC 00066
65535 - Internal Control Module Memory Error

Address 56: Radio
Part No: 1J0 035 180 B
Component: Radio DE2 0004
Coding: 01031
65535 - Internal Control Module Memory Error

EXCESSIVE COMMS ERRORS

EXCESSIVE COMMS ERRORS

Looking at the partial scans from several different vehicle platforms listed below, it is quite obvious to see that they all suffer from the same ailment commonly known as--Excessive Comm Errors--from Audi to SEAT, from VW to SKODA. Many VAG car owners have attached their own prefixes to it, like "vag com excessive comm errors", "vcds excessive comm errors", " note excessive comm errors", "vcds lite excessive comm errors", "auto hvac excessive comm errors", "address 08 excessive comm errors", but they all mean the same thing. It says that the scan tool could not communicate with said module because of some obstacle . Perhaps its conflicting with an after market Radio installation on Address 56 or  a combination of VCDS software/protocol/cable. The reason could also be that some other module on the network had been incorrectly configured (module coding) causing the scan tool to struggle to identify said module and after several times attempts fail (timeout) and presents a "Note: Excessive Comm Errors" and perhaps flag a 01044- control module incorrectly coded DTC as well.  However this isn't always the case, because it could also be caused by a setting on the scan tool software--flow control, start and stop bits, etc. The HVAC-address-08, ABS Address-03, Airbag Address-5 etc.. speak protocol KWP-1281 or protocol KWP-2000 and if the incorrect protocol has been selected, the  "Note: Excessive Comm Errors" does pops up. Some HVAC module will also generate a U0324  DTC  meaning that the scanner software is incompatible with the HVAC Control Module or the module concerned. If VCDS doesn't work, try the older VW Tool software or Commander 5,  which I have found has better HVAC and engine fan control settings than VCDS with a VAG-K-CAN cable or KKL-VAGCOM cable. I think the most common reason for excessive comm errors is using the incorrect interface cable because a KII-USB  (K2-USB) cable will not work on cars manufactured after 2005 and a Micro-CAN cable will only work on cars built prior to 1996. So it you have a later vehicle, get the right cable or invest in a Auto Boss V30 or a Launch X31 scan tool because they tend not give  Excessive Comm Errors that the VCDS software/protocol/cable combination is so notorious for. 


Address 01: Engine ---------------------
Chassis Type: 6K - Seat Ibiza / Cordoba
Controller: 6K0 906 032 AC
Component: ME7.5.10 4192
Coding: 00001
Shop #: WSC 06402
Note: Excessive Comm Errors

Address 01: Engine ---------------------
Chassis Type: 6L - Seat Ibiza/Cordoba
Note: Excessive Comm Errors

Address 01: Engine
Chassis Type: 70 (7D - VW Transporter)
Part No: 022 906 032 AF
Component: MOTRONIC ME7.1 G 0003
Coding: 00003
Shop #: WSC 27441
Note: Excessive Comm Errors


Address 02: Auto Trans
Chassis Type: 70 (7D - VW Transporter)
Part No: 01P 927 733 CG
Component: AG4 Getriebe 01P 4893
Coding: 00000
Shop #: WSC 00000
Note: Excessive Comm Errors

Address 03 ---------------------
Controller: 6Q0 907 379 L
Component: FRONT ABS MK60 0101
Coding: 0001097
Shop #: WSC 31414
Note: Excessive Comm Errors

Address 03: ABS Brakes
Chassis Type: 70 (7D - VW Transporter)
Part No: 7D0 614 111 B
Component: ABS/EDS 5.3 D00
Shop #: BB 24258
Note: Excessive Comm Errors

Address 08 ---------------------
Chassis Type: 1M - Seat Leon/Toledo
Controller: 1M0 820 043 D
Note: Excessive Comm Errors
Skipping Address 15-Airbags

Address 08 --------------------
Chassis Type: 4B - Audi A6 C5
Controller: 4B0 820 043 P
Coding: 00063
Shop #: WSC 02325
Note: Excessive Comm Errors

Address 08 --------------------
Chassis Type: 1M - Seat Leon/Toledo
Controller: 1M0 820 043 E
Component: 1M-CLIMATRON
Coding: 00043
Shop #: WSC 06402
Note: Excessive Comm Errors

Address 08: Auto HVAC
Chassis Type: 8D - Audi A4 B5
Controller: 8L0 820 043 D
Component: A4 KLIMAVOLLAUTOMAT_D75
Coding: 04144
Shop #: WSC 06325
Note: Excessive Comm Errors

Address 08 --------------------
Chassis Type: 1M - Seat Leon/Toledo
Controller: 1M0 820 043 D
Component: 1M-CLIMATRONIC X0605
Coding: 00043
Shop #: WSC 06441
Note: Excessive Comm Errors

Address 09: Cent. Elect. -----------
Chassis Type: 9N - VW Polo
Part No: 6Q1 937 049 D
Component: 0000 BN-SG. 1S34
Coding: 00012
Shop #: WSC 06402
Note: Excessive Comm Errors

Address 09: Cent. Elect.  -----------
Part No: 6Q1 937 049 D
Component: 00BP BN-SG. 1S34
Coding: 09358
Shop #: WSC 31414
Note: Excessive Comm Errors

Address 15: Airbags ------------------
Chassis Type: 6Y - Skoda Fabia I
Controller:
Note: Excessive Comm Errors

Address 15: Airbags
Chassis Type: 70 (7D - VW Transporter)
Part No: 1J0 909 603 BM
Component: AIRBAG VW3 - V04
Coding: 16973
Shop #: WSC 02743

Note: Excessive Comm Errors

Address 17: Instruments  -------------
Part No: 6L0 920 801 A
Component: KOMBI+WEGFAHRSP VDO V13
Coding: 00145
Shop #: WSC 00000
Note: Excessive Comm Errors

Address 17: Instruments ---------------
Chassis Type: 6L - Seat Ibiza/Cordoba
Part No: 6L0 920 801 A
Component: KOMBI+WEGFAHRSP VDO V13
Coding: 00145
Shop #: WSC 00000
Note: Excessive Comm Errors

Address 17: Instruments
Chassis Type: 70 (7D - VW Transporter)
Part No: 7D0 920 902 T
Component: T4-KOMBIINSTR. VDO V01
Coding: 03235
Shop #: WSC 02743
Note: Excessive Comm Errors

Address 19: CAN Gateway ---------------
Chassis Type: 6L - Seat Ibiza/Cordoba
Note: Excessive Comm Errors

Address 19: CAN Gateway
Chassis Type: 70 (7D - VW Transporter)
Part No: 6N0 909 901
Component: Gateway K<->CAN 0001
Coding: 00001
Shop #: WSC 02743
Note: Excessive Comm Errors

Address 25: Immobilizer  --------------
Chassis Type: 9N - VW Polo
Note: Excessive Comm Errors

Address 25: Immobilizer
Chassis Type: 70 (7D - VW Transporter)
Part No: 6X0 953 257
Component: IMMO 0008
Coding: 00001
Shop #: WSC 20309
Note: Excessive Comm Errors

Address 35: Centr. Locks
Chassis Type: 70 (7D - VW Transporter)
Part No: 7D0 959 800 C
Component: Funksteuergerát 0001
Coding: 00001
Shop #: WSC 02743
Note: Excessive Comm Errors

Address 44: Steering Assist ------------
Chassis Type: 6Y - Skoda Fabia I
VCID: 55AA04A28569
Note: Excessive Comm Errors

Address 56: Radio ---------------------
Chassis Type: 17 - VW Golf Citi
Controller: 17S 035 186
Note: Excessive Comm Errors

Address 7E: Ctrl Head Dash -------------
Chassis Type Audi TT
Protocol: KWP2000
Controller:
Note: Excessive Comm Errors

TORQUE RELATED EPC ISSUES

FUEL PRESSURE EPC PROBLEMS

EPC problems are a pain in the butt, they just complicate your life, make you late for appointments, leave you stranded on highways when you least expect it.  Makes you curse and cuss and make you want to fit a accelerator cable but these issues as not limited to VAG cars, as can be seen in the pics. At times EPC faults even endanger your life when they occur on the freeways, especially in fast flowing traffic when limp mode doesn't even enable you to get your vehicle off the road and out of harms way quick enough as not to be the cause of an accident. EPC fault are so darn frustrating. EPC faults are so  time consuming and EPC faults are so expensive to repair, hence many a VW, Audi, Skoda and Seat driver attempts to self diagnosis and repair their own vehicles. I have found that EPC faults can be really crappy to diagnose because the ECU's  firmware and switching hardware is in control and operates at high speed and therefor cannot be measured, unless you have a multi-channel digital storage oscilloscope. Since there are not ECU timing charts available to accurately pinpoint the causes of ECU problems, we hear many stories, in which the VW, Audi, Skoda and Seat agents are stymied by the EPC light, loss of acceleration and limp mode home. Several Audi, VW, Seat and Skoda driver can relate such stories. Stories  of taking their vehicles to the relevant sevice agent only to be told that they found nothing wrong, with the car, they then clear the DTCs saying it was just a sporadic / isolated event or often times they suspect and change some expensive components,  exorbitantly  bill for it, yet never solve the problem because within two or three days the EPC problem strikes again. This peculiarity of the EPC problem tends to go away the following day and the car drives as if there was never any problem. It is so intermittent that the vehicle just borders on becoming unreliable. That really sucks.

What I have found,  is that when an EPC related problem occurs, a DTC is flagged and stored in memory for later retrieval, meanwhile the EPC light is triggered and stays on, with the result that the engine only revs to 1200 RPM. Since the light is already on, even if a second or third EPC problem occurs, there is no way to tell because additional EPC problems won't make the yellow /amber EPC light glow any brighter. However if the DTC of the first EPC fault is different from the second of third, additional DTCs will be observed when the memory is retrieved. Should an EPC fault occur and trigger the EPC light, and a second is not undetected over a successive distance of approximately 1000 km, it is automatically erased from the memory and the EPC light will go off. EPC light problems are predominantly found on electronic Drive by Wire systems because they are torque driven. Whenever a problem occurs in the electronic Drive by Wire circuit, the EPC circuit / system acts as a safety measure to prevent injury to the occupants and the car itself by going into limp mode.

It is quite common for the PWM Signal from the ECU to the fuel pump control module to fail, resulting in the EPC light switching on and the vehicle going into limp mode. It is quite easy to verify whether or not the ECU was at fault because by disconnecting the battery and reconnecting it  after a few minutes, it resets the ECU's clock since it doesn't have backup power.  Removing the battery does not delete DTC memory nor the learnt ECU adaptation values so its quit safe to do. It however triggers a  manufacturer specific 18010 DTC - Power Supply Terminal 30 missing, or a generic P1602 DTC -Voltage too Low, Intermittent  which will be sen the next tie you connect to a scan tool.

Normally whenever the ECU detects a fault, like a missing pulse or an intermittent connection it calculates a substitute value from other available signals and makes an emergency running mode available to keep the vehicle driving.  I have noticed what's different between the electronic Drive by Wire systems and the rest of the on-board systems is that the ECU does not provide a substitute signal for torque related  / electronic drive by wire faults. So if either  G79 or G185 or both fails,  it results in no throttle response but the ECU does not generate a substitute signal, it rather just goes into emergency mode and switches on the EPC light. Like wise if G187 or G188 or both fails also, resulting in no throttle response the ECU again does not generate a substitute signal but rather goes into emergency mode and switches on the EPC light. When N30, N31, N32 or N33 fails or any of the the Ignition Coils fails, the  EPC light as well as the Mil light switches on but since the engine runs rough, its easy to isolate and remedy. When the wastegate bypass regulator valve or the fuel pressure regulator valve  fails, frustrating limp mode and the EPC light once again spoils your day.

AUDI EPC LIGHT PROBLEMS

AUDI EPC LIGHT

It is common knowledge that EPC light problems have been haunting Audi drivers incessantly for the past few years, announcing itself on Audi A1,  Audi A2, Audi A3,  Audi A4,  Audi A5, Audi A6,  Audi A7,  Audi A8,  Audi Q3,  Audi Q5, Audi Q7, the Audi RS4,  Audi RS6, Audi RS8, Audi R8, Audi S4, Audi S6, Audi S8 and Audi  TTs even before they're run-in. Several Audi owners are dismayed that EPC problems present themselves on virtually new cars. 

In fact, EPC problems pop-up at any time, on any Audi new or old fitted with X-by-Wire technology. Any Audi  without a throttle cable, is naturally fitted with a full Drive-by-Wire system which is supervised by the Electronic Control Circuit (EPC)  / Electronic Throttle Control (ETC)  that turns on the dashboard mounted EPC (K132) indicator light when it detects a malfunction, then registers Diagnostic Trouble Codes (DTC)  in the ECM memory.  Even though the EPC light turns on exclusively for  non-emission related faults, it does however turn on along with the MIL for emission related faults. 

The EPC  / ETC is a torque monitoring circuit and monitors for torque discrepancies and torque inefficiencies and when it detects one, sends the vehicle into emergency running mode (limp mode). These are prevalent when towing, when driving up an incline, when in manual mode, when in cruise control, after spirited driving, etc, and may even cause the ABS, ESP   lights to came on. Some drivers, assume  that it's happening more frequently over time and others are concerned that the EPC trouble are going to get worse because of its  randomness. But this is not the case. 

Bear in mind that once the EPC light is on, no other EPC related fault is going to make it glow any brighter. Once it's on, it's stays on even if the battery is disconnected, and it will come back on when you reconnect. However, the ECU will monitor the EPC circuit and if the same error does not occur in three successive trips of at least 7 kilometers, it will erase the DTC and it would seem as if it never happened, until the next time.  These are safely features specific to Drive by Wire systems and their workings can be viewed in the adaptation groups when retrieving errors with a scan tool.

ADAPTATION GROUPS PERTAINING TO EPC

Group 60 -- Throttle Valve Adjuster / Adaptation Epc-system

Group 61 -- Epc-system / Throttle Valve Adjuster (System 1) 

Group 62 -- Epc-system / Throttle Valve Adjuster (System 2)

Group 63 -- Kickdown Function

Group 66 -- Cruise Control Status

AUDI EPC LIGHT RELATED DTC

18039 / P1631 - Accelerator Position Sensor (G79): Signal too High 

18041 / P1633 - Accelerator Position Sensor 2 (G185) Signal too Low

18042 / P1634 - Accelerator Position Sensor 2 (G185): Signal too High

18047 / P1639 - Accelerator Position Sensor 1/2 (G79/G185): Implausible Signal 

 00777 - Accelerator Position Sensor (G79): Implausible Signal

No response from the throttle even with your foot flat on the accelerator pedal.. There are two potentiometers fitted to the accelerator pedal which are monitored by the ECU and when it it detects an intermittent signal from one pot, it turns on the EPC light then uses the second pot for acceleration but it is limited. When both pots detected as are intermittent, EPC light goes on and engine only runs at idle speed. When this error occurs, turn the engine off, stomp on the accelerator a few times through its full travel.  It could just be specks of dust that settled on the one of the potentiometer (variable resistors) tracks that stymied the ECU for a few millisecond or so. I this happens often and thereafter, presenting a 18047 / P1639 or 18039 / P1631 or 18042 / P1634 or 18041 / P1633 then consider replacing the accelerator pedal.

No response from the throttle even with your foot flat on the accelerator pedal. There are also two redundant potentiometers in the throttle body that determines the throttle valve angle and it has three modes of failure. One for when the valve angle sensor fails, one for when throttle valve actuator (motor) malfunctions and one for when throttle valve position is cannot be recognized by the ECU. When this happens  the ECU shuts off the voltage supply to the actuator, causing the throttle valve to defaults to mechanical stop position and the engine speed is limited to 1200 RPM. If any of the DTC fault below show up in your scan, check the 6 pin plug interfacing with the throttle body. It would be best to redo adaptation thereafter before thinking of replacing the throttle body. 

000289 / P0121- Throttle Position Sensor (G69): Implausible Signal - Intermittent

16506 / P0122 - Throttle Position Sensor (G69): Signal too Low - Intermittent

17987 / P1579 - Throttle Actuator (J338): Adaptation Not Started - Intermittent

17976 / P1568 - Throttle Actuator (J338): Mechanical Failure 

17972 / P1564 - Throttle Actuator (J338): Under-Voltage during Basic Setting 

17952 / P1544 - Angle Sensor 1 for Throttle Actuator (G187): Signal too Large - Intermittent

16606 / P0222 - Angle Sensor 2 for Throttle (G188): Signal Too Low - Intermittent

000547 / P0223 - Angle Sensor 2 for Throttle (G188):Signal Too High - Intermittent

17581 / P1173 -  Angle Sensor 2 for Throttle Actuator (G188) Signal too High 

18042 / P1634 - Accelerator Position Sensor 2 (G185): Signal too High 

You have difficulty starting but eventually does start but idles very rough, bucks and surges when you attempt to drive it. The   EPC, MIL (Check engine light)  and ESP lights come on. This is most likely caused by the Injectors  N30-N33 or the Ignition Coils N (1st cylinder), N128 (2nd cylinder), N158 (3rd cylinder) and N163 (4th cylinder) since both the Injectors and Ignition coils causes exactly the same symptoms. It also   exhibit the following DTCs.

17633 / P1225 - Fuel Injector for Cylinder 1 (N30): Short to Ground  - - Intermittent

17634 / P1226 - Fuel Injector for Cylinder 2 (N31): Short to Ground  - - Intermittent

17635 / P1227 - Fuel Injector for Cylinder 3 (N32): Short to Ground  - - Intermittent

17636 / P1228 - Fuel Injector for Cylinder 4 (N33): Short to Ground  - - Intermittent

MORE EPC PROBLEMS

J757 Engine Component Power Supply Relay cause loss of  high-pressure and turns on EPC. ESP and MIL lights.

N75 Solenoid valve for charge pressure limitation and turns on the  EPC and MIL lights but shown no symptoms of failure except go into limp mode. 

Audi A1, Audi A2, Audi A3, Audi A4, Audi A5, Audi A6, Audi A7, Audi A8, Audi Q3, Audi Q5, Audi Q7, the Audi RS4, Audi RS6, Audi RS8, Audi R8, Audi S4, Audi S6, Audi S8 and Audi  TTs EPC Problems.

KNOCK SENSOR

VAG KNOCK SENSOR K1 AND THE EPC LIGHT

VW, Seat, Skoda  and Audi Knock sensors have become quite notorious for sending the car into "limp mode". Limp mode is a safety feature on all Drive by Wire vehicles, implying an EPC-electronic power control-but no accelerator cable. EPC implies torque control. By analogy,  its something like a horse that gets spooked and takes off at high speed and out of control with its rider unable to rein him in,  or a frayed accelerator cable that becomes stuck while driving at high speed. That's just a recipe for disaster. Imagine stepping on the brake pedal but the high revs of the engine just forces the car forward, smoke pouring from the brake pads to the point that the become glazed and  no longer has any effect. Pushing the transmission into neutral isn't an option because without the load, the engine is destined to blow, perhaps even push a piston  through the side of the engine lock.  Drive by wire prevents this from happening and cuts power to the powertrain if it detects a fault that puts the engine at risk. Knock reacts somewhat similar to backfire since both are due to detonation and pre-ignition-incomplete combustion.

Detonation is a common problem associated with lean fuel mixture -non stichometric-and torque. The EPC light is often triggered on an incline when the torque is insufficient to pull the car uphill when in an inappropriate gear. Knock sensors can detect combustion knocks in individual cylinders. Knock sensor 1 (G61) senses cylinders 1 & 2, and knock sensor 2 (G66) senses cylinders  3 & 4. To prevent combustion knock, the ECU cylinder selective knock control overrides the electronic control of the ignition timing by retarding the timing, but may not be unable to if the Fuel Octane is too low causing secondary combustion in the cylinder. Knock sensor 1 (G61) is known to trigger EPC light and activate limp mode, hence it needs to be checked for flush engine contact and correct torque. DTC  P0171 and P0174 could show up in scans.

The ECU calculates engine ignition timing based on input signals from Throttle Position (TP) Sensor G79 and  Accelerator Pedal Position G185, the  Engine Speed (RPM) Sensor G28,  the load signal from Mass Air Flow (MAF) Sensor G70, the signal from the Throttle Valve Control Module J338,  the Coolant Temperature (ECT) Sensor G62, both Knock Sensors G61, G66 (additional G198 & G199 on V6, W8 & W12 engines) and signals from Camshaft Position Sensors G40, G163, (additionally G300, G301 on V6, W8 & W12 engines) When the engine is below 40 degrees  celsius knock sensors signals are not used to make timing decisions. What this implies is that when the EPC light turns on  when the engine is still cold, the knock sensors are not guilty , neither  the the Mass Air Flow (MAF) Sensor G70 nor the Coolant Temperature (ECT) Sensor G62 since whilst idling, have nothing to do with torque. That leaves the Accelerator Pedal with G79 & G185, the Throttle  Control body senders G187 & G188,  the  Engine Speed Sensor G28,  Camshaft Position Sensors G40 & G163 as the EPC limp mode culprits. However sensors are fairly reliable but the wiring  harnesses  are  more likely to be the cause of the problem, see wiring in Audi.

Fuel pressure regulator valve N276, the wastegate bypass regulator valve N75 and the  Ignition Coil N, N128, N158, N163 and its Power Output Stage N122 are three  more EPC culprits. Injectors N30-N33 can also cause the EPC light to turn on and cause car to go into "limp mode" but also causes the engine not to run smoothly. Once again before condemning the sensors or actuators, check the wiring harnesses to them.



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The above EPC errors are common to Volkswagen, Audi, Skoda and Seat. The  VW, the 4motion, the Amarok, the new Beetle, the Bora, the Caddy, the Corrado, the CC, the Eos, the Fox, the Golf, the Jetta, the Kombi, the Lavida, the Lupo, the Passat, the Polo, the Phaeton, the Routan, the Santana the Scirocco, the Sharan, the Tiguan, the Touran, the Touareg, the Transporter, the Vento , the Up and lastly the Vivo. The Audi A1, A2, A3, A4, A5, A6, A7, A8, the Q3, Q5, Q7, the RS4, RS6, RS8, the R8, the S4, S6, S8, Audi TT. The  Seat Alhambra, the Altea, the Arosa, the Cordoba, the Ibiza, the Inca, the Leon, the Mii and the Toledo,  Skoda  Felicia, the Octavia, the Fabia, the Superb, the Roomster, the Yeti, the Rapid and the Citigo. The Audi RS-6, A4 Fsi, Audi A4, Audi S3, Audi TT, Audi R8, audi a4 2.8 quattro 5 speed, Skoda fabia, seat leon, seat ibiza, Avant RS 2, Coupé, Audi A3 Mk1, Volkswagen Golf Mk4, Volkswagen New Beetle, Volkswagen Bora/Jetta Mk4, SEAT León Mk1, SEAT Toledo Mk2, Škoda Octavia Mk1,  TFSI, FSI, GTI, TDI,