What Does the EPC Light Mean on a Volkswagen or AUDI and How Can You Fix It?

The EPC warning light is not an uncommon sight to VW and AUDI owners and when it comes on and stays on it can be alarming. The question is though what exactly does it mean, should you be worried and if so what should you do to fix it?

In this article we will explain just what the EPC warning light means and let you know just how worried you should be. Some of the reasons it may come on may be mundane but others could be a cause for major concern so read on to find out more.

What Does the EPC Light Mean?

Car manufacturers sometimes like to give their systems different names to make them seem more innovative and this is the case with EPC. Essentially, Electronic Power Control or (ECP) is the Volkswagen Group's version of a traction control system.

Subsequently you will find this system and warning light in the newer cars from companies owned by Volkswagen including AUDI, SKODA and SEAT. This warning light essentially will appear when there is a problem from any associated system connected to traction control.

Often the ESP warning light will come on at the same time as a warning light for the engine, ABS or the ESP systems. This will give you some idea where the problem is although not always exactly what the issue is.

What Causes an EPC Light?

As mentioned there can be a few causes that will initiate the EPC warning light which can come from several different systems. These might include:

Throttle Body Failure

The throttle body is a component that controls the intake of air to the engine. When the gas pedal is depressed it opens a valve to allow the air in where it mixes with the fuel and a spark to make the combustion needed to run the engine.

If there is an issue or fault with the throttle body then you might get an EPC warning. As this component is electrical in nature and engine related you will also probably get a check engine light as well.

Failed Brake Pedal Switch

Also known as the brake light switch, the brake pedal switch as you may imagine is located in the brake pedal itself. When the brake pedal is pressed this switch sends an electrical message to the brake lights which turn on, warning drivers behind you that you are slowing down.

This switch however does more than control the brake lights as it helps the cruise control functions and of course the EPC system. If there is an issue with this switch then the EPC does recognize whether the brake has been pressed or not. This will initiate the RPC warning light and record a fault code.

Bad ABS Sensor

The anti-lock brake system (ABS) is an important part of the EPC system, The ABS sensors are found on all four wheels and track the speed at which the wheels are rotating. These sensors may become dirty or rusty over time which can cause them to fail.

If the EPC does not get information from just one of these sensors it can not function correctly. This will lead to the EPC warning light and possibly the ABS warning light illuminating on your dashboard.

Brake Pressure Sensor

Another brake related sensor, the brake pressure sensor measures the pressure applied, unsurprisingly t,o the brakes. If this sensor is at fault it can cause the EPC warning light to come on and potentially the ABS light as well.

This sensor is more protected from the elements as it is tucked away in the ABS control module. However, this does mean that if it fails then you may need to replace the whole module as there is no easy way to replace just the sensor.

Steering Angle Sensor

This sensor is located behind the steering wheel and measures the position of the steering wheel. This data is fed to the EPC which uses it to determine the direction you turn the steering wheel and correct the brake force accordingly.

If there is a problem with this sensor or the clock spring in the steering column itself then you may get an EPC warning light. This is because the system can not now determine brake force when turning.

Engine Sensor

There are a lot of sensors in the engine that are required by the EPC for correct function. It only takes one bad sensor to affect the EPC system so there can be multiple reasons from the engine alone for a warning light. Sensors that could be to blame include the MAF sensor, the IAT sensor, the ECT sensor, or the O2 sensor.

Wiring Issues

Wiring issues are very common in modern day cars basically because there is so much of it compared to years ago. All these clever systems and driver aids are electronic so they need wires. This means that wires can definitely be a possible cause of an EPC warning light.

Wires could be broken, loose, corroded or burned out. With so many that could be at fault this will likely be a tough fix and could be costly. If all of the other potential causes have been ruled out then it is most likely wiring related.

How to Fix the EPC Light

As mentioned there are several possible issues that might trigger the EPC warning light so obviously you will need to determine which one you are dealing with.

Check for Trouble Codes

Stored in your Volkswagen's computer will be a log of any and all errors that have been detected. Each error will have a code that will more specifically tell you what the perceived problem is and where it is originating from.

You can check this yourself if you have an OBD2 scanner tool or you can visit a mechanic who has even more complex scanners. In this way you can find out what the problem is without wasting money on a guess that turns out incorrect.

Test the Brake Light Switch

This is a free test that you can try to determine if the issue might be related to the brake light switch. All you need is two people, one to sit in the car when it is running and press the brake and the other to watch and see if the brake lights come on.

If the brake lights do not come on then you have an issue with the brake light switch which you definitely need to fix. This may be the cause of the EPC error as well but there is still the chance that another problem may be at play.

Review Sensor Data

Your vehicle may allow you to look at some of the data received by certain sensors including the brake pressure sensor. As mentioned this sensor can be the source of the problem so if the data levels from this sensor do not match expected parameters this may point you toward the issue.

Talk to a Pro

Self diagnosing issues related to an important and complicated system like EPC can be tricky so if you feel like it is beyond your confident skill level seek advice from a professional. Never be embarrassed to get a professional to deal with the issue because trying to fix this issue alone could cause more harm than good.

Is EPC a Big Deal?

As with most warning lights the EPC light came on for a reason and it should not be ignored. You might think that you can do fine without traction control and yes you may well do but this warning is also telling you something is wrong somewhere.

Ignoring a broken component may lead to damage of other related parts and this could quickly become quite costly in terms of repairs.

Conclusion

The Electronic Power Control (EPC) system is essentially Volkswagen's version of traction control so when there is an issue with this system it can come from several other important systems in the car including the engine and brakes.

There are several possible causes for seeing this warning light and a number of possible fixes. It is important to find out what the issue is and decide whether you are able to fix it or if you may need a professional to help you.

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  • "What Does the EPC Light Mean on a Volkswagen or AUDI and How Can You Fix It?". Tow Ratings. Accessed on March 19, 2024. http://towratings.net/blog/what-does-the-epc-light-mean-on-a-volkswagen-or-audi-and-how-can-you-fix-it/.

  • "What Does the EPC Light Mean on a Volkswagen or AUDI and How Can You Fix It?". Tow Ratings, http://towratings.net/blog/what-does-the-epc-light-mean-on-a-volkswagen-or-audi-and-how-can-you-fix-it/. Accessed 19 March, 2024

  • What Does the EPC Light Mean on a Volkswagen or AUDI and How Can You Fix It?. Tow Ratings. Retrieved from http://towratings.net/blog/what-does-the-epc-light-mean-on-a-volkswagen-or-audi-and-how-can-you-fix-it/.