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 VW, SKODA, SEAT & AUDI scans.

WHY ENGINE LIGHT COMES ON

EPC LIGHT

Seeing a VW or a Volkswagen or Polo da Volkswagen or a VAG car or a new Polo on tow,  is becoming an all too familiar site, - view picture below. VW cars are seen piggy-backed and carried to service centers on a daily bases because VW owners are encountering serious trouble with their Volkswagen cars.  

Many Volkswagen drivers are often stranded on the high ways or freeways whilst driving to and from work because their VAG cars are throwing tantrums, by going into limp mode and turning on the EPC light.  Most VW drivers have no idea why engine light comes on. 

I've been late for  meetings on several occasions because of this. On a few others, I couldn't make it to the  bank in time because the Electronic Power Control -EPC- circuit incapacitated my VW Polo Classic 2.0L Highline. The worst was when I took my daughter to the dialysis clinic and the Electronic Power Control (EPC) light came on, because I ran over a speed bump a little too fast. This resulting in "Limp Mode" causing my daughter to be substantially late for her dialysis session. This could have been a life or death situation but fortunately it wasn't.

I took this photo with my cell phone. The picture quality really isn't good, so therefore the
Bluemotion badge to the left of the right side tail light  isn't clear at all.  But I couldn't pass-up
the opportunity to capture a VW Bluemotion 2012 loaded on a roll-back.

Anyway,  lets look at why this very risky and inconvenient issue haunts most VAG car owners. All Drive-by-Wire cars (since 2000) has an Electronic Power Control (EPC) light. The EPC dashboard warning lights are not exclusive to VW or VAG cars but affects most other new cars regardless of its manufacturer though the common denominator is Drive-by-Wire and an Engine Control Unit (ECU) often called the Powertrain Control Module (PCM) with an embedded microcontroller supplied by the same manufacturer.  EPC stands for Electronic Power Control which is controlled by the ECU (Engine Control Unit). In essence the Engine Control Unit (ECU) is a microcontroller with associated circuitry which control the sub-modules in the car, all connected together by either OBD II or CAN-Bus. Certain outputs from these sub-modules can activate the Electronic Power Control  circuit, especially if the reason for sending its signals to the ECU (Engine Control Unit)  could cause damage to the engine or is a danger to the passengers. For example, if the car runs out of oil, or if the emissions exceed the prescribed level, or  if  the car hits a speed bump a little to hard or if a brake bulb fails.

In the first case the oil level sensor will detect that the lack of oil in the crankcase and since there is a possibility the engine may seize-up, it sends a pulse train to the PCM to activate the Electronic Power Control (EPC), which cuts the power to the engine, making the car go into "Limp Mode" and switching on the EPC warning light. In the second case the lambda sensors on either side of the catalytic converter  will detect the fuel rich exhaust fumes and send a pulse train to the PCM to activate the Electronic Power Control (EPC), which cuts the power to the engine making the car go into "Limp Mode", thereby limiting carbon pollution and  and switch on the EPC indicator light (epc warning light) . In the third case the engine knock sensors will detect the suspension knock as the car hits the speed bump and will send a pulse train to the PCM to activate the Electronic Power Control (EPC), which cuts the power to the engine making the car go into "Limp Mode" and switch on the EPC dashboard light. In the fourth case, one of the Electronic Control Unit or Body Control Modules (BCM) sensor will sense that a brake light is open-circuit, send a pulse train to the PCM to activate the Electronic Power Control (EPC), which cuts the power to the engine  making the car go into "Limp Mode" because in that condition the car is not roadworthy. The EPC dashboard light is a very graphic demonstration that there is something amiss in you VAG that needs to be remedied.

There are several other sensors strewn throughout the car and many of them can have an effect on the Engine Control Unit (ECU) and cause the EPC light to come on. Sometimes when the EPC fault light comes on, it may be a spurious error, based on past driving cycles. A driving cycle is calculated from the time the engine starts and drives -which should be a min 5 minutes- until the engine is switched off. It could  take three drive cycles to clear a spurious error but if the fault persists it has to be diagnosed on a VAG-COM diagnostic tester.

Should you require more information on,  what is epc light, what is a epc light, vw epc warning light, vw epc code, epc on a vw, epc warning light vw, epc vw tiguan,  epc on jetta, epc light on, what is the epc light,   epc fault light, checkout epc-demystified.

Here are some Non  Volkswagen Websites I highly recommend,  

http://electroniques.blogspot.com

http://photojani.blogspot.com

http://expowp.blogspot.com  

EPC LIGHT

EPC LIGHT

A few months ago the battery in my VW Polo Classic remote key, gave up the ghost.  I used the remote key to lock the car and set the alarm / immobilizer the night before but it refused to open the doors the following morning. So I unlocked the car with the key.  That’s when I realized that my 2007 VW Polo Classic Highline only has one door lock and that I only had access via the driver’s side door.   Neither the left side passenger door nor the rear doors on either side have any locks keyholes. This didn't surprise me because cutting cost has become the new standard in new car design. By not fitting these legacy locks, the car manufacturer saves the cost of three locks, the internal door mechanisms and the labour cost to install them when the car is assembled.  Multiply this amount of savings by the entire vehicle production for the year and you can surely see their total saving.

The Battery inside the electronic key housing.

That brings me to another cost saver implemented in most cars manufactured during 1996 and later. If you heard about OBD II (On-Board Diagnostics II) and CAN-Bus (Controller Area Network-Bus), you will have some notion what I am talking about. With the implementation of CAN-Bus auto electric wiring has been reduced to a bare minimum.  The average older car had between 300 – 400 meters of wiring, used for its head lights, tail lights, windscreen wipers, horn, dashboard electrics, alarm system, central locking, interior lighting etc, etc ...  Much of this wiring are roughly the same thickness (0.5 - 1.5 mm square) to carry the required current to the various devices.  But inside the engine compartment there are numerous thicker wires for the starter, ignition, air conditioner fan motor, alternator, main supply to the fuse box as well as  earth straps to mention but a few.   All these copper wires range between 1.5mm square – 15mm square, some of which are tin plated to minimize corrosion. Not only is this 400 meters of copper wiring expensive, it also weights a good 60-70 kgs.

By embracing the CAN-Bus technology, manufacturers save on the purchase of about 50Kgs of copper wire. Fifty kilograms of copper wire multiplied by the annual car production gives you some idea of the overall saving. Fifty kilograms taken off the weight of a car also gives it a better 'power to weight ratio' hence making it more fuel efficient.  With CAN-Bus technology,  all the  control modules in the car are interconnected, on a serial data network, each module taking charge of a sub circuit of  the electrical system. These modules are network similar to USB (Universal Serial Bus) used in computer networking.

VW EPC LIGHT

However,  CAN-Bus and OBD II was not implemented to save copper, nor to lessen the weight of cars neither to make cars  more fuel efficient.  It was firstly agreed upon by the EPA, then legislated by several Governments whose countries manufacture cars, to install an EMS (Engine Management System) in every new car built after 1996. This management system would monitor the engine and transmission of the car and insure that 'engine emission levels' stayed within a predetermined margin of compliance.  If this level is exceeded due to engine malfunction, the embedded diagnostic system should be able to recognize it and recorded such malfunction and also alert the driver with some form of MIL (Malfunction Indicator Light). Alternatively turn on the EPC light (Electronic Power Control - epc warning light) and stops the  car from revving up or  inhibit the management system and shut the car down.  The frequency of engine misfires or malfunctions are recorded in code format (vw epc code) designed by the Society of Automotive Engineers (SAE) in the ECU's non-volatile memory which is only accessible by the service agents or by someone with a modern day ODB II / CAN-Bus compliant diagnostic scan appliance.

Anyway let me return to the story of the remote control battery. Off I went to the local VW agent to buy a replacement battery.  I drove  a good 40 Km there  and back but still returned without the battery. It was just way too expensive for a small mercury cell. Problem was, I didn't phone to find out how much it cost. At the price that this VW agent charged for the  fob key battery I could manufacture it myself and it would still be cheaper. So I scouted around at a few photographic shops for this particular battery and eventually found a pharmacy that sold them. Hypothetically, if I bought all the pharmacy’s battery stock and sold it to this VW agents at half their asking price I would in fact have made a very comfortable living.

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