Showing posts with label Throttle position sensors. Show all posts
Showing posts with label Throttle position sensors. Show all posts

Tuesday, April 19, 2016

EPC DASHBOARD WARNING LIGHT

EPC DASHBOARD WARNING LIGHT

VW, Audi, Skoda and SEAT vehicles are crammed with wonderous technology, ranging from various electronic modules that overseas their general functionality to hoards of sensors that monitor how these vehicles behave and actuators that respond to software controlled decision making elements. One could say that collectively they give cars a degree of Artificial Intelligence and their seamless integration makes motoring a lot easier. But when something goes wrong, there is also a swarm of warning lights on the instrument cluster that will flash at you until you take corrective action. However, knowing exactly what each warning light flashing on its dashboard is trying to tell you, is a completely different story. Even though some of these light are self explanatory and fairly obvious to understand, others are not, and  can be interpreted by looking in the owner’s manual. Knowing what these warning lights mean is really important to drivers because they can preempt a potential breakdown or full-on engine failure, insulating you from expensive repair bills.

As a general rule, warning lights illuminated either red or amber (yellow /orange), though a blue light is often used to indicate high beam and green lights are used to mean indicate left and right  turn signals. On a VW Polo a red warning light emphatically means that something needs to be done immediately. For example, the Oil pressure warning light, or the low brake fluid level light, or the parking brake warning light, or the Coolant level low / coolant temperature high light, illuminates red or flashes red as a danger sign and needs immediate attention. Failure to remedy can result in the engine seizing, the brakes failing, damaging your rear disks and brake pads, or the engine overheating resulting in a possible blown head gasket or worse, respectively. On different model VAG vehicles, the use of red and amber light may overlap. 

An amber / yellow /orange light  on the other hand serves to be rather informative and draws the driver]s attention to a potential problem or a problems that needs to be remedied soonest. For example the amber Anti-lock braking system (ABS) light, or the amber Airbag light, or the amber Immobilizer light, or the Brake pad wear light, or the Engine fault Onboard diagnosis (OBD) light, none of which will impede driveability nor endanger the driver. But this isn't strictly true especially when encountering the dreaded yellow EPC light


WHAT IS AN EPC LIGHT?

EPC stands for Electronic Power Control and has  much to do with controlling the electronic throttle hence it is sometimes referred to as the "Electronic Pedal Control". Probably because the throttle valve is actuated by an electric motor rather than a physical cable between the accelerator pedal and the throttle control valve. In essence the engine control unit responds to the sensor on the accelerator pedal and sends a corresponding command to the throttle valve positioner via four wires which is commonly known as "Drive by wire". But the EPC is much more than just an Electronic Pedal Control. Any malfunctions in the either the "Drive by Wire" circuit  or its associated sensors are detected by self-diagnosis and indicated by the EPC warning light.

The Electronic Power Control (EPC) is a circuit made up of various engine components or sub circuits that collectively addresses torque. In reality it should have been called "Electronic Torque Control". Should  a problem arise in the torque system, it correspondingly illuminates the easily identifiable yellow/amber/orange word "EPC" in the instrument panel.  The EPC circuit's decision making elements are embedded into the ECU which is responsible for the electric throttle valve positioning and overall torque-oriented engine management.

As such the ECU has to gathers all torque demand inputs in order to correctly calculate the appropriate control actions. These inputs includes, the Engine speed, the Engine load signal fetched from the air mass meter, the Vehicle speed, the shift point of an automatic gearbox, whether or not the air conditioner compressor is ON or OFF, whether or not the the cruise control system is engaged, whether or not the Traction Control System is engaged  or the braking  system is applied.

The combination Brake light / brake pedal switch provides a braking input to the ECU, failure of the switch to send data of the drivers foot on the brake pedal can trigger the EPC light in certain VAG vehicles, but definitely on the VW Polo. Don't be fooled by the brake lights that are working, when the brake pedal is depressed because it does not imply that the brake pedal switch is functioning as it should. In similar fashion the Clutch Pedal Switch provides cruise control input to the ECU, engaging the clutch, automatically disengages the cruise control which could also trigger an EPC episode.

This EPC light will come on when there is a problem:-

1) With either of the accelerator pedal senders.
2) With either of the throttle angle senders.
3) With the throttle valve control unit
4) With the accelerator / throttle harness.
5) With the throttle adaptation.
6) With grime and carbon build-up in the throttle body. 
7) If the the Throttle Valve Control Unit is replaced.
8) With the Brake Light Switch
9) With one of the Knock Sensors.
10 With the Mass Air Meter (MAF).
11) with the Engine control unit
12) With the Ignition system
13) With the Fuel injection system
14) With the ABS
15) With the Power-assisted steering system
16) With Lambda regulation (fuel consumption signal)
17) With the Alternator
18) With the TCM

Bearing in mind the throttle valve control unit is located on the intake manifold and needs to ensure that the engine is supplied with the appropriate and proper air flow. By implication the MAF measures the air flow and should there be a problem with it, the  ECU will not be able to calculate the proper torque and possible go into EPC mode. The consolation is that every fault that occurs would normally create a DTC entry. So the best way to determine the cause of the EPC light coming on, associated with loss of power and limp mode, is to do a diagnostic scan. 


Links to other EPC Problems!
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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.

Saturday, June 6, 2015

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.



EPC light
Epc light?
EPC light on
EPC light problem
EPC warning light?
EPC and ESP Problems
EPC and ABS warning lights on
EPC warning light, advice welcome
EPC Light and stalling
EPC what does this mean?
Epc Light that keeps coming on
EPC light and starting issues
EPC light come on frequently
EPC light pain in my butt
Epc Light On Power Loss
EPC warning light - car shakes violently - ideas?
EPC light & locked in Park. 2006 A6, need solution.
EPC light / Check Engine light - Audi not finding issue
EPC light came on and can't start the engine
EPC light coming on and difficulty starting
EPC warning light and stalling in traffic
EPC warning light is on the dash and another lamp
EPC light came on and there was lots of shudder
EPC light has just come on and doesn't go away
The EPC light came on and I had sluggish power
The EPC warning symbol came on today while driving.
The EPC warning light has been triggering fairly regularly
The warning light EPC does not go out or comes on or flashes
Occasionally the EPC light comes on
EPC Light comes on at 4000 rpm - clears on restart
EPC warning light?? 15 Nov 2011
EPC Light comes on at 4000 rpm - clears on restart 3 Mar 2011
My EPC and CEL (Check Engine Lamp) is on
My EPC light is now light on the dash
My EPC light goes on/off on a daily basis
My check engine light and EPC light is on
My Audi's epc light came on this morning
My epc light and check engine light came on
My EPC light came on then I tried to start the car but nothing happened
What is the EPC warning light?
what's the mean of epc light, when it's come on ?
When I start the car the EPC light on the dashboard stay on
when epc light's come on, car loosing power
What is epc warning light mean on a seat ibiza
Check Engine Light & EPC Light came on
When you try and accelerate the EPC light comes on and the throttle cuts out
Why does the epc light keep coming on in my audi a4
A4 with EPC light, stalling at dangerous times
Audi Q7 EPC engine management warning light
I have EPC warning light and acceleration problems
I'm having a problem with the EPC light on my 2003 Audi A4 2.0FSI
I keep getting the epc light come on
j'ai le voyant EPC qui reste allumé
Having EPC problems with a skoda fabia 1.4
Seat Leon 52 plate EPC light
Seat ibiza 1.2 EPC and Engine light on
Seat Ibiza EPC light on and acceleration problem?
Fabia EPC Light on
Seat arosa EPC light?
How do I reset a Seat Arosa EPC light?

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, 

Tuesday, October 21, 2014

EPC DEMYSTIFIED CONTINUED 2


Continued from EPC DEMYSTIFIED CONTINUED 1.


  ...  I only became aware of this when my EPC light went on due to the knock sensor. See picture blog.  More...


 PART 3


BREAKING THE CODE

What needs to be mentioned as a basis of understanding, is that OBD (on-Board Diagnostics) was introduced in the 70's along with CDI (capacitive discharge ignition systems) as DIY kits. Few cars had fuel injectors, points and coils were fast being taken over by electronic modules. During this time some standards were introduced but they were not very well defined and as such manufacturers developed their own and applied their specific systems and developed their own code descriptions which later became known as OBD1. This was considered undesirable and counterproductive since none franchised service, and general mechanical repair centers had to purchase different scan tools, interface cables and connectors, skills and manuals for each make and model of car they specialized in. This resulted in vehicle diagnostics becoming unwieldy expensive. In February of 1986, Robert Bosch founder of Bosch, introduced the CAN (Controller Area Network) serial bus system to  the Society of Automotive  Engineers (SAE) in motor town of Detroit.

This influenced the  Society of Automotive  Engineers (SAE) who subsequently drafted a list of standards and practices that aught to be implemented by all automobile  manufacturers and recommended them to the Environmental Protection Agency (EPA). The EPA weighed-up these standards and recommendations, acknowledged their benefits, and adopted them. The standards criteria included a precisely defined diagnostic connector for each auto manufacturer, a standard scan tool and a common electrical communications protocol and a common data format, and the ability to monitor other
vehicle parameters. Lastly that the standard scan tool should interface with vehicles of all manufacturer. It also included mandatory definitions and descriptions for certain emission control system  defects which was labeled the ‘P0’ Codes. Manufacturers were allowed to generate and use their own ‘manufacturer specific code descriptions’ known as ‘P1’ Codes. This collaboration of standards became known as OBDII, (OBD2) and was adopted for implementation by January of 1996. Two types of scanner codes, namely manufacturers codes like VAG codes and SEA Codes are now the standard practice.

OBD-II  

As mentioned above, Powertrain Control Module (PCM) error codes are assigned the prefix P and pertain to the, Engine management, Transmission management, Fuel Pump and Gasoline Management, Automatic Transmission – Hydraulic Control, Emission control system, evaporative emission purge control (HVAC), Auxiliary module management and other some 0n-board Hybrid application.  For example P1340  suggests that the Powertrain triggered a DTC and describes it as an "Crankshaft-/Camshaft Position Sensor Signals Out of Sequence"

From the above example it would thus be easy to interpret the DTC below relating to EPC (Electronic Power Control)

DTC (VAG)   DTC (SAE)  Society of Automotive  Engineers

16504 P0120 Throttle Position Sensor A - Circuit Malfunction
16505 P0121 Throttle Position Sensor A - Circuit - Performance Problem - Out of Range
16506 P0122 Throttle Position Sensor A Circuit - Low Voltage Input
16507 P0123 Throttle Position Sensor A Circuit - High Voltage Input
16894 P0510 Throttle Position Sensor - Closed Switch- idle micro-switches -F60 malfunctioning
17951 P1543 Throttle Actuation Potentiometer - Signal too Low
17952 P1544 Throttle Actuation Potentiometer - Signal too High
17913 P1505 Throttle idle micro-switches -F60 not/short-circuit opens
17914 P1506 Throttle idle micro-switches - Switch Does Not Open/Short to Ground
17988 P1580 Throttle Actuator (B1) Fault - May be caused by low battery if found with 16487 (P0103)

18038 P1630 Accelerator Pedal Position -G79 signal too small  (low)
18039 P1631 Accelerator Pedal Position -G79 signal too largely (high)
18040 P1632 Accelerator Pedal Position -G79 supply voltage malfunction
18041 P1633 Accelerator Pedal Position -G185 signal too small
18042 P1634 Accelerator Pedal Position -G185 signal too largely
18047 P1639 Accelerator Pedal Position 1+2 Range/Performance -G79 and -G185 implausible signal
18048 P1640 Internal Controller Module defective (EEPROM) Error

EPC Circuit.

The EPC  circuit consists of a number of disparate components that control and supervise, regulate and determine the throttle valve position at all times. They include;

1) the accelerator pedal position sender (TP sensor G69)
2) the accelerator pedal position sender -2, (G185)
3) Black 6-pin plug with 6-pin with Gold plated contacts

NB! The above three components are part of the accelerator pedal.

4) the throttle valve control module (unit),
5) the K132 EPC fault lamp, (electronic throttle control fault indicator)
6) the engine control module (unit).

Firstly we going to do a test on components 1, 2 and 3 above. To do this test, you need a Fluke multimeter or similar for a voltage and continuity / resistance test. Unplug the 6-pin plug from the accelerator pedal and switch on the ignition. Connect the multimeter and check for a 4.5 volt reading between;-

pin 1 and ground, then between pin 1 and pin 5
Pin 2 and ground, then between pin 2 and 3.
If tests prove to be "OK", switch ignition off.
Do additional checks for short circuits between one another and ground and if this checks "OK",

Locate the ECU, normally inside cowl. Disconnect the ECU from its socket, identify pins 34 & 34, 35 & 36, and 72 & 73 on the socket. Disconnect the 6-pin plug from the accelerator pedal once again and check for continuity between this plug and the ECU socket. There should be continuity between pins:-

1 of the 6-pin plug and pin 72 of the ECU socket.
2 of the 6-pin plug and pin 73 of the ECU socket.
3 of the 6-pin plug and pin 36 of the ECU socket.
4 of the 6-pin plug and pin 35 of the ECU socket.
5 of the 6-pin plug and pin 33 of the ECU socket.
6 of the 6-pin plug and pin 34 of the ECU socket.

Any resistance above 1.5ohms should be investigated for corrosion. This often causes the engine to surge (idle unevenly or rather breaths) However, if this test proves "OK" and no wiring malfunction is detected, replace G69 and G185 (single unit) on the accelerator pedal. NB! these components are non adjustable and needs to be replaced as a whole.

When the ignition is turned on, the ECU checks all EPC components necessary for the proper  functioning of the Electronic Power Control. If a malfunction is detected in the EPC (Electronic Power Control) system whilst the engine is running, the ECM will simultaneously activate the EPC (Electronic Power Control) warning light and make an entry of this malfunction in  the ECU (electronic Control unit) DTC (Diagnostic Trouble Codes non-volatile memory.  By a process of eliminate the EPC fault can be fixed.

The list below categorises VW and Audi manufacturer predetermined data groups which varies depending on the vehicle, year, engine, engine code and management system on board.

Group Number / Group Category

1–9     General engine activity data
10–19 Ignition data
20–29 Knock control data
30–39 02 sensor control system data
40–49 Three-way CAT data
50–59 Engine speed control data
60–69 Throttle drive data
70–79 Emissions reduction data
80–89 Special function data
90–97 Power increase data
98–100 Compatibility data
101–109 Fuel Ignition data
110–119 Boost pressure control data
120–129 Control unit communication data
130–150 Special info data

Based on the data from the above table EPC problems are associated with group 60-69. However, on Expert Systems Diagnostics Group 60, holds the EPC Adaptation data, group 61 holds EPC-system 1 data and group 62 holds the EPC system 2 data. Group 66 holds the speed-o-cruise data.

NB! If you found this information useful, please link to this page.

EPC DEMYSTIFIED CONTINUED 1


Continued from EPC DEMYSTIFIED.  


  ....But it’s not that simple. There is a lot more to it than meets the eye.....

 PART 2



But it’s not that simple. There is a lot more to it than meets the eye. Cars exclusively use embedded microcontrollers (µContollers) with embedded firmware in preference to microprocessors with loadable software. In order for a microprocessor to function properly in any device, it must contain dedicated internal circuitry and firmware specific to its function, have inputs and outputs and an oscillator circuit among other circuitry and an OS (Operating system). A DVR (Digital Video recorder), or a PVR (personal Video recorder) or a set-top-box or embedded network appliance or data router are just a few examples of such systems. µControllers  are less significant and less sophisticated than microprocessors, more dedicated to its specific need, often cheaper, faster, safer and smaller. Embedded µControllers are therefore the natural choice for car manufacturers. And there are several manufactures that produce µControllers families specifically for the motor trade.


So it should be understood that companies like Bosch, Digifant, Delco  and other engine management ECU manufacturers and electronic module manufacturers uses the same microcontroller chip families or similar microcontroller chip families, designed and manufactured for them by a selected few silicon chip manufacturers.  In the same vein, computer manufacturers like IBM, Dell, Sony, Toshiba and Lenovo, etc. all use microprocessors manufactured by Intel Corporation or AMD in their laptops and computers, whereas Apple uses microprocessors manufactured by Motorola.

Baring in mind, that much like Motorola, Intel Corporation and AMD produces different featured microprocessor chips with different instruction sets,  along with their auxiliary support chips for low-end and high-end computers; such as 4 bit, 8bit, 16bit, 8086 family of chips, 32bit Pentiums, I5, I7, 64bit, XEON, 128bit big Endian and small Endian microprocessors etc; so does Infineon, Altera, Freescale, Atmel and ARM etc, manufacture different featured microcontroller chips for both low-end cars and high-end cars which are specifically chosen for their internal features and software by the various ECU and electronic module manufacturers like  Bosch,  LUCAS, DENSO, Delco, DELPHI, FENIX, HITACHI, HELLA,  MARELLI, Siemens, etc. These microcontroller chip families can roughly be categorized into four sub sectors, those specific to Powertrain functions (P), those specific to the Body and Safety functions (B), those with specific functions for Chassis (C) and those specific to Internal Convenience & communication(U).

In a nutshell all the sub systems in your vehicle are controlled by these on-board computer chips, each at the heart of an electronic module flanked by associated components and sensors. Each of these modules are in fact a fully fledged computer in its own right, situated in various positions throughout the car and linked together by a wired networked called a network bus and all are accessible through the Databus diagnostic interface for adaptation.

When the ignition is switched on, several dashboard warning lamps light-up and stays lit for the duration of the internal test cycle (<30 seconds). Should all tests check OK, all lights goes however if all systems does not check out OK, the relevant light will stay on and a fault will be logged in memory . After the car is started, the ECU monitors all sensors  and continually takes readings from the complete range of powertrain modules and sensors. These readings are then compared with default readings stored in the operational logic of the  system. Should the sensor reading coincide and agree with the stored program value or values, the microcontroller will send the  required outputs to the relevant actuators, for example the injectors. If the sensor readings differ and are out of specification,   "not within the required limits",  it will take another and if this sensor reading continues to be ‘out of limits’ a DTC will be triggered and sent to non-volatile memory. Depending on the nature of the fault, the embedded program may or may not instruct the microcontroller to make internal changes, thus operate on different criteria until a repair is effected, or until the fault has been cleared.

So whenever a mechanical or electronic problem arises in either the Powertrain (P), the Body (B), the Chassis (C) or the internal Conveniences & Communication (U) areas, the relevant module or modules triggers the on-board self diagnostics program and generates a DTC (Diagnostic Trouble Code) which is then stored in the non-volatile memory of the ECU for later retrieval by mechanical technicians. At the point When a DTC code is logged in memory, the system self-diagnosis system also alerts the driver with a visible indication  of trouble by turning on a warning light on the dashboard like the "EPC light", or the "Malfunction Indicator Lamp" (MIL) which on European cars is known as the "Check Engine Light". This doesn't tell you  the nature of the problem, even though it could be something serious, or not. After the necessary repairs are completed, a diagnostic scan tool should be used to clear the DTC errors  and to turn the malfunction indicator light (MIL) or EPC light off. Thereafter the car should be taken on a short test dive to ascertain that the previous drive issue or issues are resolved. Then the car should be hooked up to the diagnostic scan tool once again in order  to confirms that the DTC or DTCs is also no longer present.

The nature of such mechanical problem may  prevent the engine from starting or it may idle erratically, switch off immediately after starting, refuse to rev higher than 1500 rpm and impede driveability (limp mode), difficult cold starting, misfire, lazy acceleration, high idling speed, fluctuating rev counter, excessive fuel consumption, difficult warm starting, excessive black smoke, poor engine response or emits blue/grey smoke,  etc ... Each of these faults and so many others each produce individualized codes.   In most cases it would be expedient to engage the services of a roll-back to get your car to a VW service center so that diagnostics can be run on the car.

With sufficient knowledge and an appropriate diagnostic apparatus (Autoboss, Pico Scope, Range, VCDS, AutoEnginuity,  ScanXLpro), code reader or scanner, plugged into the car's 16 pin diagnostic plug, mechanical minded persons can read these faults, print then or save them to an SD card or harddrive, send signals and communicate with the ECUs, read the measured values and interrogate the actuators. The DTC in memory however do not identify the part that has gone faulty but rather provides you  with a general idea to its area of origin. Often long before a DTC code is generated the fault may already have existed so when the you view the DTC it could show that the fault occurred twice of thrice or even six times before. The ECU software is designed to monitor the frequency of error and if it is an isolated occurrence the ECU clears the fault after a certain distance is traveled but that dependent on the severity of the fault. For arguement's sake lets say 300kms. If it happens once in 300kms it could automatically clears the fault but should it happen four times during the same distance a DTC will be registered, the car could go into limp mode since it may be unsafe to drive the car if it's a breaking or steering issue, or shut the engine off if the O2 sensor went faulty and can't regulate the smoke pollution, or disable starting if the knock sensor triggered the DTC as there may be no oil in sump which could amount to a very expensive engine repair. In the case of the latter, the oil light should have illuminated long before the knock sensor shuts the engine off. However I have encountered a problem with the wires that plug into the oil sensor that became brittle due to engine heat and  subsequently broke off. As a result the sender  sent the low oil condition but it never arrived at the the ECU hence did not turn-on the oil-low light. I only became aware of this when my EPC light went on due to the knock sensor. See picture in blog.   More ...



EPC DEMYSTIFIED


EPC DEMYSTIFIED IN THREE PARTS

PART 1


In a global village where defined lines between languages and nationalities, technologies and terminologies have become completely blurred, it is important to create terms of reference in discussions, so that we are all on the same page but pronunciation can at times offend the ear. To elaborate, some people say "tomarto" (tomato) some say "tomayto", some say micro computer and some say microprocessor, some say Electronic power control (EPC) some say Electronic Pedal control (EPC). But that's just semantics, the bottom line remains, that it establishes a common ground for people of different geographical spaces to discuss common topics.

In response to the hoards of queries I recently received and the abundance of confusion there is out there about EPC (Electronic Power Control); and in reply to the thousands of e-mails I received regarding EPC (Electronic Power Control) that I haven’t been able to reply to as yet nor will ever be able to, I decided to dedicate the next few episodes of my blog to explaining the EPC (Electronic Power Control) problem many VW drivers and VW owners are having with their cars as if they were two year olds. (Not that two year olds can relate the subject at hand).

I have explained EPC in previous blogs, namely EPC light revisited explained and EPC why-engine-light-comes-on, however, I am going to elaborate on the EPC (Electronic Power Control)  concept and demystify it for the benefit of all these people mentioned above and all those destined to encounter this problem at some time or the other. The question is not if you will encounter an EPC problem but rather when you going to encounter an EPC problem, its just a matter of time. Be that as it may, for the sake of simplicity, and by analogy, I'm going to compare the workings of the EPC (Electronic Power Control) in a car to that of a PC (personal Computer) which in my humble opinion will aid understanding.  So here goes....

Electronics as a whole has intrinsically influenced human life globally, especially since the advent of the silicon chip. Through the evolution of said silicon chip, Microprocessors have become so common place, that it finds itself in virtually every modern day technological advancement from computers to televisions, cell phones to cameras, medical equipment to the very cars we drive, to mention but a few. As a result virtually everyone out-there, has heard of, or are familiar with the terms microprocessor, microcomputer or just computer, and as such, it establishes a basis to discuss familiar concepts. Most people in the "Secular World" either owns a computer or uses computers and accordingly have some understanding of its hardware and its software, and how well these complement each other and seamlessly work together. I mentioned this purely in preparation to my assertion that  follows. However, all those non-technical and all-thumbs people and those  who say "you don't have to know how an engine works in order to drive a car", are totally excused.

EPC for Hands-on Dudes, Savvy Ladies and other pragmatic people.
Computers can roughly be subdivided into building blocks, each of which is responsible for a specific function or a collection of functions. As such a combination of these specific functions gives rise to the correct and proper functionality of the computer or computer based device. For instance, the computer hard drive functions as the storage unit that holds the operating system, application programs and user data. The DVD Rom, serial port, keyboard and mouse acts as input devices. Whereas and the speakers, printer & screen act as output devices, doubling-up as the interfaces of information interchange between man and machine (computer). The motherboard houses the CPU (central Processing Unit / Microprocessor chip) it ancillary / auxiliary timing chips, control and data buses, RAM and sub circuitry for  AGP, PCI, MR1, PCMCIA, USB, Ethernet, Fire wire, parallel connectivity, etc. When all these specific components play together nicely, we are guaranteed a fully functional computer and a happy computer user.

Likewise the car can be subdivided into building blocks each responsible for a specific function. In this instance, the engine is the source of propulsion which delivers it to the rest of the drive train. The instrument panel, the steering wheel, the transmission and the braking system constitute some of the input and output devices, also   doubling-up as the interfaces of information interchange between man and machine (car). The electrical system; the ECU (Motronic control unit), Control unit within the dash,  along with its auxiliary modules, oversees the overall timing, sensor, actuator, control and data bus, as well as block components like the Radio, air conditioner and central locking etc. Once again, when all these discrete components play nicely together, we have a perfectly functional car and a happy driver / owner. More...