Showing posts with label throttle body. Show all posts
Showing posts with label throttle body. Show all posts

Saturday, September 2, 2017

Volkswagen and Audi EPC

Volkswagen and Audi EPC

The Internet is a huge repository of  information, some useful  and some not so useful, or more to the point, useless. But, there is so much of both, duplicated and reechoed  in posts like auto-facts, axleaddict, youfixcars, and motor forums by so many individuals. There is nothing worst than being led up the garden path by some ignoramus who knows squat about electro-mechanical engineering technology when you are desperately looking for answers. To reduce that from happening, I decides to bust some of the myths related to VAG cars that are being echoed over and over and over.


EPC can be a bitch to repair.

Myth 1
Here's the first myth from someone on Yahoo Answers, relating to a 2012 VW Polo. "You can clear fault codes by disconnecting your battery for a while".  And here's another, "just disconnect the battery on your Audi A3 for a little more than 10 seconds and your fault codes will be  gone"! 

Myth 1 Busted
Though the above is true for pre-1996 vehicles fitted with OBD-I, disconnecting the battery on any car manufactured post-1996 fitted with OBD-II will definitely not delete any fault codes because the ECU stores all DTC (Dignostic Trouble Codes) aka fault codes codes in its  non-volatile memory.  What it will do, is reset the cpu / timer. The term non-volatile memory is generally used for all types of solid state memory, meaning memory that doesn't need its contents refreshed periodically. 

However, the ECU also stores learnt values and basic settings, like for example the Fuel Control Learning Adaptation Values and the Kick-Down Position of the Accelerator which is needed by the automatic transmission. This data and your car's radio code is not stored in non-volatile memory and will undoubtedly be erased when the battery is disconnected.  Once the battery is reconnected, the adaptation process needs to be done which will enable the ECM to learn the new settings for the Drive-by-Wire electronic throttle  valve and store it. If you didn't save the radio code you have to go to a VW / Audi dealer with your VIN and they may be able to give it to you.

When you disconnect your car's battery, the ECU detects the loss of battery power and registers a DTC in the ECU's non-volatile memory to that effect. This record can be seen after the battery is reconnected and a  diagnostic scan is performed.  It would look something like this,

2 Faults Found:
00532 - Supply Voltage B+ 
            07-10 - Signal too Low - Intermittent

01598 - Drive Battery Voltage 
            07-10 - Signal too Low - Intermittent

Removing the negative terminal of the battery isn't all bad, it does have the advantage  of resetting  the system's ECU safety watchdog timer. A safety watchdog timer (WDT) is responsible for periodically generating a system reset in the event of a software glitch. This one of a kind CIC61508 safety watchdog timer is ASIL-D (Automotive Safety Integrity Level D) approved,  where level D refers to the highest classification of initial hazard against the risk of injury as defined within ISO26262 automotive industry standard.


Infineon Safety Watchdog timer 

Pressure Sensors


Myth 2
There are pressure sensor in the VW and Audi engine block that causes an EPC light to come on and make the car go into limp mode.

Myth 2 bustedYes, there are pressure sensors in both VW and Audi engines but they not fitted into the block and should not be mistaken for than for knock senors that are screwed to the block. Faulty or loose knock sensors can cause the EPC light to come on and send the car into limp mode.  The baro sensor measures the ambient air pressure and has a effect on engine performance altitude dependent.  The supercharger boost pressure is controlled via the regulating flap control unit Intake manifold pressure sensor/MAP sensor (MAP = Manifold Air Pressure) which can cause the EPC light to come on and send the car into limp mode. The high-pressure fuel pump delivers fuel at a pressure of up to 150 bar and any drop in this pressure can cause the EPC light to come on and send the car into limp mode. Common problem with loss of pressure is the fuel filter. Loss of oil pressure can cause the EPC light to come on and send the car into limp mode. Lastly there is high system pressure in the cooling system at high revs and sudden loss of this pressure can cause the EPC light to come on and send the car into limp mode.

Myth 3
EPC light usually means that the Electronic Throttle Body needs replacing and reprogramming.  

Myth 3 busted It is advantages to perform adaptation on the throttle body, before attempting to replace it with a new throttle body . Often times replacing it makes no difference and normally turn out to be the wiring harness connectors to the throttle body that's defective.   Disassemble the three electrical connectors around the throttle body clean  this inside of the connectors with circuit cleaner and reassembled. Also check for vacuum leaks, especially pressure regulator hose and the small pipes connected to the intake-manifold before replacing anything.

Myth 4
Epc light is mostly known to come on when there is emissions problems. 

Myth 4 busted This is incorrect because the 'check engine light' is specific to emission related problems, however The EPC light may also come on if the emission related problem affects the engine torque. So repairing the emission related problem first would in most cases reset both the EPC light and the 'check engine light'.


Sensors associated with EPC

Extensive safety measures have been designed and implimented 
in both the hardware and software of Audi and VW.  In most cases dual sensors are used for continual self-checking of signal plausibility. A safety watcg dog timer is integrated in the Motronic ECM to constantly and continually monitor the processor for correct and proper operation. Some of the sensors are listed below.

Fuel Pressure Sensor G247
Low Fuel Pressure Sensor G410
Oil Level Thermal Sensor G266
Heated Oxygen Sensor (HO2S) G39
Heated Oxygen Sensor (HO2S) 2 G108
Oxygen Sensor (O2S) G130 &  G130
situated behind 3 Way Catalytic Converter (TWC) G130
G186 Throttle Drive  (EPC))
G187 Throttle Drive Angle Sensor 1  (EPC))
G188 Throttle Drive Angle Sensor 2  (EPC))
Engine Speed (RPM) Sensor G28
Mass Air Flow (MAF) Sensor G70
Throttle Position (TP) Sensor G79
Accelerator Pedal Position Sensor 2 G185
Clutch Position Sensor G476
Throttle Valve Control Module J338 
Throttle Drive Angle Sensor 1 (EPC) G187
Throttle Drive Angle Sensor 2 (EPC) G188
Camshaft Position (CMP) Sensor G40
Camshaft Position (CMP) Sensor 2 G163
Engine Coolant Temperature (ECT) Sensor G62
Engine Coolant Temperature (ECT) Sensor G83 (on radiator) 
Knock Sensor (KS) 1 G61
Knock Sensor (KS) 2 G66
Brake Light Switch F

Thursday, June 23, 2016

WHAT IS A VW EPC WARNING LIGHT

What Is a VW EPC Warning Light

The EPC warning light is an instrument cluster based LED found on all Volkswagen, Audi, Seat and Skoda vehicles fitted with a drive-by-wire system and EPC stands for Electronic Power Control. However the EPC warning light is not exclusive to these VAG cars, most other motor manufacturers also have them, since it's legislated to be part of the OBDII system. This EPC light when lit displays the letters EPC and primarily warns the driver that there is problems in the engine's torque system - (acceleration system). The reason why the EPC turns on, problem could be many, among which are the vehicle's knock sensors, its throttle system, its cruise control, its mass air flow system, its engine speed verification system or any of the other associated systems that cooperate in the drive-by-wire schema. 

When this EPC light comes on, the vehicle’s throttle valve (butterfly) may be limited in order to protect the engine from damage. It prevents the engine from revving above 2000rpm. This is known as limp mode and the ECU permits just sufficient power to drive the vehicle to a service center for repairs. To remedy the problem, the vehicle’s ECU should be scanned with an automotive diagnostic too, in order to extract the DTC's related to the torque problem.  Cars with an accelerator cable are also fitted with an EPC light but the ECU software is quite different, yet the overall principal remains the same.

All Volkswagen (VAG) vehicles have a whole array of dashboard warning lights in their instrument panels, specifically designed to alert the driver to any vehicle malfunctions or problems. In fact so does all most modern day automobiles. Having said that, it is only a matter of time before these lights start lighting up. Invariably and inevitably all cars will breakdown at sometime or the other but its nice to be warned about a mechanical problem before it actually occurs. For example, having a low coolant level light or an low engine oil-level light flash at you, accompanied by an audio alert is a blessing because complete loss of either coolant or engine oil could result in a very expensive repair. 

The one warning light that puzzles most drivers is the VW EPC warning light. Driver often ask, what is the VW EPC warning light? Like I've mentioned above, it is a bright yellow dashboard light with the letters EPC inscribed in bold.it  When lights-up to draws your attaention to a potential malfunction in the EPC system. When it lights up whilst driving and the trouble is related to a safety issue, the car will more than likely go into limp mode. This may sound quite serious but in most cases it's not. There are several reasons why EPC Dashboard Warning Light turns on, but through a process of elimination the cause can be tracked down fairly easily. 

The Engine Speed Sensor is  known to cause the EPC light to turn on. The engine speed sensor is a proximity magnetic transducer counting the revolutions of the flywheel / crankshaft and sends a steady stream of pulses to the ECU. So when this stream of data is interrupted for whatsoever reason for only a fraction of a second, the ECU  detects this and turns on the EPC light and cuts power to the engine. It does this to protect the engine from damage. 

If you have a scan tool, check for DTC errors. The following error code, 17745 /P1337, 17746 / P1338, 17747 / P1339 and 17748 / P1340 are the troubles codes that provides a  tell tail sign that the engine speed sensor is either loose or faulty, hence the car's engine cuts-out whilst driving and the speedometer is inoperative.  But in some cases the engine will start again. When this symptoms repeats itself often, you should know it is time to replace that pesky engine speed sensor.

The Accelerator Pedal itself is often the main culprit that causes EPC problems. A telltale sign is that the engine idles a lot faster than it aught to. To verify this, physical pull the accelerator pedal away from the floor board while the car is idling. If it reduces the engine's revs back to normal, then it is time to replace it, because the potentiometers that's built into the the accelerator pedal, have gone faulty. Accelerator pedal problems are numerous and the following DTC, 16504 / P0120, 16505 / P0121, 16506 / P0122, 16507 / P0123, 18038 / P1630, 18039 / P1631, 18040 / P1632, 18041 / P1633, 18042 / P1634, are linked to accelerator pedal errors. 

Mass air flow sensor is another engine component that can cause the EPC light to turn on. Cleaning the  mass air flow sensor with compressed air does often solve the problem but if the issue persists, its time to replace mass air flow sensor. But before changing it, check to see if any of the rubber hoses in its vicinity isn't perished. An leak in Air Intake System wil allowing air unmonitored to enter the intake which will throw a P2279 / 15093 error or a P0068 / 15101 error.


The Throttle body is by far the most common cause of an EPC problem though in many cases it is not the throttle body that's at fault but rather that it the needs to be recalibrated (adaptation). The scan codes like P2135 / P2136 / P2137 / P2138 / P2139  and P2140, will give a  good idea as to whether or not the throttle body require replacement.  But in many cases it turns out to be  wiring harness issue. The plugs that connects the throttle drive motor and the throttle position sensors is fairly troublesome ad should be checked before throttle is replace.

The Brake light switch can also cause the EPC light to come on because the torque control circuit uses the brake light signal as a ECU input signal when the car decelerates.  

The Injectors and the Ignition Coils can also cause the EPC light to turn on. I've heard that an incorrect spark gap on the plugs can also cause an EPC problem but haven't experienced it yet.  Driving with very little gasoline in the tank can also cause the EPC light to turn on because the high pressure fuel pump may lose pressure which then notifies the ECU to inhibit the torque circuit and switch on the EPC light and make the car go into limp mode.

I've experienced the Knock Sensor turn on the EPC light. Spirited driving also turns on the EPC light.

So as you can see there are several things that can cause an EPC fault.  This is not a complete list of EPC problems but as new ones are identified, I will post them.  The following questions prompted me to write a synopsis of what an EPC light is!

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What is an EPC light? What is an EPC warning light? What is an EPC light on Volkswagen? What Is the VW EPC Warning Light? What is the EPC light on a Volkswagen Jetta? What is EPC on a Volkswagen? What does it mean if the EPC warning light comes on in a Volkswagen? Volkswagen - EPC Warning Light, What does an EPC light on the dash of a Polo match car mean? EPC light came on and lost all power. 

The EPC warning symbol came on today while driving. EPC Light and stalling. EPC light came on and can't start the engine. EPC light on, what does it mean ? EPC light and engine check light. EPC warning light. Epc light. EPC + power loss/no boost.  Do not exceed 4000 rpm  EPC light.   EPC error where the car shakes terribly.  ESP EPC & Engine Light ON.  EPC Light and Stalling. Polo bluemotion 58 plate and a yellow engine light came on. I read the manual but still not sure something to do with the exhaust??

A little help as my wife needs the car for work.2002 1.6L GOLF, EPC light on. POWER LOSS An EPC light will appear on the dash randomly whilst driving. Once it is on, there is a noticeable loss in power and it stays this way until the... volkswagon polo epc warning.step by step guide to turn light off please, preferably without visiting expensive vw garage. Have diagnostic computer to see code! EPC light came on and engine will not rev higher. I have a vw polo and the EPC warning light has come on what should i do? Orange light 03 vw polo. VW Polo Map sensor fault code idling poorly. EPC light on my dashboard 2001 vw polo. It has something to do with the engine management, retarding the power of the engine.

Wednesday, July 29, 2015

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.

Tuesday, July 28, 2015

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
-------------------------------------------------------------------------------
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.

Wednesday, April 8, 2015

EPC NIGHTMARE

EPC WARNING LIGHT

Over the past 3 years I have had some  13775 EPC information requests. That's roughly 4500 request per year, each and everyone of  them EPC related.  I manages to help several Vag car owners with their EPC problems however many were unable to give me the  DTC codes that could be causing the EPC problems. So, If you have a scan of your car feel free to upload it to my blog, I will analyse it and post the answer for everyones benefit.  I have found that the commonest EPC problem is the accelerator pedal potentiometers. However they cannot be purchased as a separate item. You have to buy the complete accelerator pedal. There is a plug that is attached to  the accelerator pedal, the plastic bit where the yellow stickers are, contains the pots.  If you are having EPC problems you are not alone. Read some of your fellow Vag car owners woes.




NO EPC DTC CODES

What is EPC on a Volkswagen? My car loses power all the time. If  I turn the car off and leave it for a while,  the problem goes away. This happened to be a couple of months ago, and  I was forced to take  it to a VW dealer.  They had no idea what to do. The car idles  really badly and the EPC light is on from the moment I start it,  besides now the check engine light is also on. I'm  thinking about replacing the throttle body but it cost about is $600. That's crazy man.

TOO VAGUE & NO EPC DTC CODES

My EPC light came on and car lost all power, so now I am having the most weirdest problems. I got stuck on the freeway, my EPC light came on and I had to pull onto the shoulder of the road because I lost acceleration. Disconnected and reconnected the negative battery terminal to reset the system, then she was driving fine. Took it to VW guy but he has no idea what an EPC problem is or at least he wanted me to  pay him  first before would help. He wants $85 an hour.


NO EPC DTC CODES, CAN'T ASSIST

I have an  VW Polo 1.4 and the 'Check Engine light' and EPC warning light  blinks for the past few months. Replaced the throttle body and potentiometer  and wiring to the engine manifold were replaced.  The same problem still persists and car  will stall at random causing these warning lights and EPC to switch on.

NO EPC DTC CODES, NO HELP

My polo 1.2  epc light comes on when I stop at traffic lights and goes into limp mode then can only drive  15 mph max without   pressing the accelerator. Took  it to a service agents who condemned  the throttle body, so had it replaced. The EPC light still comes on.


Feel free to upload your VWSKODASEAT & AUDI scans.

Thursday, February 7, 2013

VAG


VW DIY

In the not so distant pass, whenever something went wrong in your VW, Polo, Jetta, Passat,  AudiSeat or Skoda,  you could do one of two things. Either  take it to a VW specialist to have it checked out or you could fix it yourself, if you are a hands-on, DIY kind of person. Nowadays the latter option has faded away into obscurity. With the stream of problems VAG cars are having, many of us are in the dark regarding repairs. We make educated guesses, replace parts by substitution, often costing huge amounts of money for repairs and the fault still persists. Below I have out-lined some of the problems I have encountered and with any luck shed some light on the problems you've been having with your VAG car. But before I go any further you may be itching to ask "What is a VAG car?"

Well, VAG stands for Volkswagen-Audi GMBH in Germany, also refers to Volkswagen Aktiengesellschaft or Volkswagen AG for short and Volkswagen-Audi Gelelschaft (Geleslschaft means Association). In essence, it's the same, exact and identical  group. And any car manufactured or sold by them is referred to as a VAG car. Amongst these are, VW, PoloJetta, Passat, Audi, Skoda, Touran, Tauareg, Beetle, Tiguan, Golf, PorscheAmrok,  RabbitBentley, BugattiBora, Phaeton, Vento, Kombi, Transporter,  Lupo and the  Lamborghini, each one with a different engine with varying capacities with obscure three letter abbreviations like, BBX, AAF, AEX and APE amongst many others. However many of them have the same or similar Electronics Bosch Motronic system hardware with software ranging from ME 5.x to ME 7.x, with several support modules in common, networked to the OBD II / OBD2 (On-Board Diagnostic System ver. 2) or Can-Bus (Controller Area Network) standard.

The VW Polo 2007 with new Bluemotion technology can switch its engine off
when it comes to a halt, yet plagued by the legacy VW EPC light problem.

The idea behind this is so that only the  Volkswagen dealership technician are supposed to do the servicing and perform repairs to your car. The VW car manuals specifically discourages anyone other than qualified or trained mechanics /auto-electricians and technicians or mechanicians to perform servicing, especially changing codes and performing readiness testUnder the OBD II and Can-Bus standard, an ECU (Engine Control unit) interfaces with various other modules fitted in the car and controls and manages all sub-circuits. For example, Central Electronics Module, ABS module, Temperature Control Module, Speed-o-cruise Module, etc... When one of these modules detects a fault with one of its components, it registers a error in the non-volatile memory. Lets say you have a front wiper motor problem and it just wont work, but the fuses are OK. Even if you suspect the wiper motor as faulty and it actually is faulty and you replace it, the new wiper motor still wont work after its been replaced and switched on. You first have to clear the error or errors  from non-volatile memory with a diagnostic tool. Then and only then will it work.  

I've had the same results with my power steering which just wouldn't work after some work was done to my car and in the process the Power Steering Motor was disconnected. When it was reconnected the power steering was very stiff and difficult to steer. After going through the entire process of checking and back-tracking it still didn't work. Eventually, when the diagnostic tester was plugged in, two errors codes showed up. The first indicating that the +30V supply had dropped to an unreliable level and the second a power steering error. The first was because the battery was disconnected and the second was because the power steering plug was disconnected. After erasing the two error codes from the non-volatile memory, the power steering work perfectly normal.

I can assuredly say that I am not alone or rather that my car trouble is not unique, neither am I the only VW owner having car trouble (see previous blogs).  It appears that my 2007 Polo Classic Highline shares most of the problems listed below with my fellow VW owners. There are probably hundreds if not thousands of other  VAG car owners experiencing the same issues with their cars as I am experiencing with mine. Here are just a few of the problems that my fellow VW owners shared with me :-

"VW polo dashboard brake light stays on" / "EPC instrument fault indication light is on" / "VW polo warning lights on dashboard" / "VW  polo classic is showing epc light, starting and dying" / "polo dashboard controls" /  "VW  polo warning lights off power steering" / "warning light on dashboard" / 2007 volkswagen polo problems" / "audi electronic power control indicator" / "won't rev" / "VW Polo EPC Warning Light" / "golf mk4 dashboard warning lights" / "epc instrument fault indication" / "VW  door key problem" / "VW  polo accelerator position sensor (g79)" VW throttle body sensors"

NB! Fellow VW drivers found this site to be helpful and was interested in checking out the following sites as well.

expowpphotojanicontroversy365nerdytoyslovelifelovehealthsightsofcapetownsowpboxelectroniquesblogspot-atphoto-magixgodssitesglycomixarth-ritisforex-bidfoodsofthecapelanguagesbarrier, pimpyocare-gimos.

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Wednesday, January 30, 2013

VW ELECTRONIC POWER


EPC LIGHT EXPLAINED

As I mentioned before in my older blogs, the new generation of VW cars are designed to turn on an EPC Light (not check engine light) so that only the  Volkswagen dealership service technician or technicians are supposed to do any an all servicing and repairs.  The VW workshop manuals specifically discourages anyone other than a qualified or trained mechanics / auto-electrician and automotive technician to perform servicing, especially changing codes and performing readiness test.  This is because  incorrectly set readiness and adaptation settings can completely disable your car and virtually render it useless. To repair it would then cost a small fortune.

CHECK ENGINE LIGHT

An earlier blog, covers some late model VAG cars with fuel injection and electronically controlled throttle body instead of the traditional accelerator cable controlling the throttle valve. It is called Drive-by-wire or DBW for short. When the Engine Control Unit -ECU, which invariable is a computer in its own right detects a fault  Diagnostic Trouble Code - DTC  in the Drive-by-wire system, it registers a fault Diagnostic Trouble Code - DTC in its non volatile memory and turns on the EPC light, disables the accelerator and throttle bodylimit the engine to a maximum of 1500 rpm -"Limp Mode".  This would be sufficient power to "Limp Mode" the car to a service centre without causing further damage to the car or unduly polluting the air should the fault cause it to smoke. This is a safety precaution and can be equated with, what would happen if  an accelerator cable got stuck in the downward position. Disaster could follow. The Engine Control Unit -ECU collects faults Diagnostic Trouble Code - DTC from all senders and stores an internal list, which is only visible with a diagnostic tester. Diagnostic Trouble Code - DTC can range from excessive emissions to - intermittent air bag connections, from brake light failure to - depleted brake pads, from interior ultrasonic failure to - immobilizer problems to even disconnecting the battery. Each of these faults generates codes, some of which can be viewed in future blogs.

Should the Volkswagen Engine Control Unit -ECU  considered a Diagnostic Trouble Code - DTC to be so serious that it could possibly do harm to the engine or the environment, it will inhibit the throttle function and limit the engine revs or even disable starting or idling completely.  Unfortunately the only way to repair such problems, is to connect the  Volkswagen Golf,  Jetta, VW Polo, or Volkswagen Beetle, to a dignostic tester through its CAN-Bus / OBD2 / OBDII port and view  Diagnostic Trouble Code - DTC  if any and  Diagnostic Trouble Codes, clear them from memory and perform corrective procedures.  Below is an overview of the Electronic Power Control Circuit - EPC and how the Drive-by-wire system operates.
The basic operation of  the Electronic Power Control (EPC) Schematic showing inputs
from drive-train sensors and output signals to drive-train actuators.

Other INput senders could result in similar problems. For example - the Oxygen Sensor could detect that the exhaust fumes carbon mixture exceeds the prescribed level which is toxic to  the atmosphere and the environment. It could disable driving of the vehicle by enabling the Electronic Power Control Circuit - (EPC), turning on the EPC warning light or even disable starting not allowing the car to idle. This could be due to a dead plug causing the idling to be erratic and not burning up all the fuel. This un-burnt fuel will invariably change the exhaust fumes composition which triggered the Catalytic Converter and Oxygen Sensor in the first place.

Like wise, when the brake light bulbs blow or the fuse to the brake circuit blows, an INput signal from the brake light sender could also activate the Electronic Power Control Circuit - (EPC), turning on the EPC warning light causing the car to go into "Limp Mode" because driving a car on a public road without brake lights is an accident just waiting to happen. In fact the Engine Control Unit (ECU) looks upon this car as non-roadworthy as a safety procedure. In a previous blog I described an Electronic Power Control Circuit - (EPC)which switches on the EPC light problem caused by an INput  signal from one of the knock sensors with the same results as above. Other senders INputs that can cause similar problems are:-

The Engine Speed Sender G28 situated at the flywheel.
The Hall Sender G40 situated at camshaft pulley
The Hot Air Mass Meter G70 and intake Air Temperature sender G42 situated near intake manifold.
The Lambda probe G130 situated upstream of catalytic converter
The Lambda probe G39  before catalyst converter
The Knock sensor I - G61 below intake manifold
The Knock sensor II - G66 below intake manifold
The Accelerator Position Senders G79 and G185 embedded in accelerator pedal (EPC Problem)
The Clutch pedal switch F36 situated in the drivers foot well.
The Brake light switch F and brake light switch F47 situated in the drivers foot well.
The Throttle control valve / motor drive assembly  J338 
The Angle Senders  G187 and G188 situated inside throttle body.
The Fuel Pressure Sender -G247

NB! VAG car owners who found this site to be helpful 
were interested in the following sites as well.

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