DIAGNOSING EPC LIGHT PROBLEMS

DIAGNOSING EPC LIGHT PROBLEMS

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

Audi and VW crankshaft position sensors.

Question?

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

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

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

5 Faults Found:

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

Answer!

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

Question?

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

Answer!

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

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

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.

______________________________________

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.

______________________________________

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?

______________________________________

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

-------------------------------------------------------------------------------

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 - - 

-------------------------------------------------------------------------------

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.