What are the Causes of EPC Light Illumination? | How to Fix the EPC Light on Volkswagen or Audi?

Your vehicle dashboard contains different warning lights and warning symbols. The EPC warning light is the most common warning light in Volkswagen or Audi. This warning light indicates an issue with your EPC system. This article explains the EPC light meaning, its causes, and how to fix it.

What does the EPC Light mean?

EPC stands for Electronic Power Control. The EPC light is a warning light that specifies an issue with the Electronic Power Control (EPC) system of your vehicle. When the EPC light starts illuminating, it generally indicates a problem with the throttle system of the vehicle.

Your vehicle’s EPC light may appear along with the ESP light, ABS light, or engine light that depend on the cause of the problem. The electronic control unit (ECU), steering control unit, transmission control unit, and brake control unit of your vehicle monitor the functionality of the Electronic Power Control system (EPC).

EPC Light

The electronic control unit (ECU) or powertrain control module (PCM) of the vehicle is considered the vehicle’s “brain” that ensures the efficient working of the engine, transmission, and other parts.

The Electronic Power Control (EPC) system works with the electronic control unit to monitor the functionality, and if there is a problem, the EPC immediately turns on a warning light on the dashboard to alert the driver.

The check engine light may also start illuminating along with the EPC light, depending on the fault condition. In such conditions, your vehicle’s cruise control system can be automatically disabled, and electronic stability control can be disabled.

To prevent your engine from severe damage, the EPC can initiate a “limp mode.” This mode reduces the engine power and gives an indication to the driver that the vehicle is stalling.

What Causes the EPC Light to Come ON?

The following are the major causes of EPC light illumination:

  • Bad Throttle Body
  • Bad ABS Sensor
  • Bad Brake Pedal Switch
  • Faulty Brake Pressure Sensor
  • Bad Engine Sensor
  • Bad Steering Angle Sensor
  • Wiring Issues

1) Bad Throttle Body

A bad throttle body is one of the major causes of the illuminated EPC light. The main function of the throttle body is to control the amount of air drawn into the engine when the accelerator pedal is depressed. Your vehicle’s EPC system uses the data of the throttle body to control engine performance. This system doesn’t work efficiently when the throttle body goes bad.

bad throttle body which causes to illuminate the EPC light

The latest throttle bodies are electric. Therefore, when an electric throttle body goes bad, it turns on the check engine light and EPC light.

Read More: Bad Throttle Body Symptoms and Causes

2) Bad ABS Sensor

A bad ABS sensor is also a major cause of EPC light flashing. Most commonly, each wheel has an ABS sensor. The ABS sensor of your car measures the speed of each wheel. The ABS system of your vehicle mainly uses the data of the ABS sensor, but some other systems utilize this data, including the EPC system.

ABS Sensor

The ABS sensor is installed on the wheel’s hub. The water, rust, dirt, etc., may cause a bad ABS sensor. The ABS resistance ring of your ABS may also have an issue where the ABS sensor measures speed.

Read More: Bad ABS Sensor Symptoms and Causes

3) Bad Brake Pedal Switch

When the driver presses the brake pedal, the brake light switch or brake pedal switch informs the EPC system of your vehicle to turn on the brake lights. The brake pedal switch is also used for other jobs, such as the EPC system or cruise control system.

When your brake pedal switch goes bad, the EPC system can’t identify whether the brake pedal is pressed or not. In such case, the EPC light of your car will start flashing, and a trouble code will be stored.

4) Faulty Brake Pressure Sensor

A faulty brake pressure sensor in your Volkswagen car is one of the major causes of the illuminating EPC light. This sensor works similarly to a brake light switch, but instead of just measuring on/off, it calculates the brake pressure that the driver is applying to the brake pedal.

Brake Pressure Sensor

In maximum Volkswagen models, the brake pressure sensor is usually installed inside the ABS control unit, which makes it hard to replace. In such a configuration, if your brake pressure sensor goes bad, then the entire ABS control module usually has to be replaced, which may be costly.

5) Bad Engine Sensor

Your vehicle contains multiple sensors that monitor the working of the engine. Different control units of your vehicle use the information of these sensors to regulate different functionality. The EPC system uses the information of the engine sensors to function efficiently.

MAF Sensor, mass air flow sensor

A problem with one of the engine sensors can cause the EPC light to illuminate on the instrument panel. Therefore, when the EPC light comes on, you should immediately read the error code so that you can identify the main issue.

The oxygen sensor, ECT sensor, IAT sensor, or MAF sensor are the most common engine sensors that can trigger the EPC light.

6) Bad Steering Angle Sensor

The steering angle sensor is located just behind the steering wheel. This sensor measures the position of your car’s steering wheel. The EPC system uses the data of the steering angle sensor to find the direction in which the driver steers the steering wheel and corrects braking effort based on this information.

There is also a clock spring for the steering wheel buttons and the steering wheel sensor cables to allow the steering wheel to be rotated. If this clock spring goes bad, your steering angle sensor can’t work efficiently.

7) Wiring Issues

The damaged wiring is one of the major causes of the illuminating EPC light. However, it is very hard to find the wiring issues unless you know exactly what you’re looking for.

Burn contacts, corroded electrical contacts, or broken wires are the major wiring issues. If you are unable to find the wiring issue and your EPC light is still flashing, you should contact a professional mechanic as soon as possible.

How to fix the EPC Light?

To fix the VW EPC light, use an OBD-II scanner and read the stored codes. After reading the codes, you need to find the root cause of these codes.

Follow the below-given steps to fix the EPC light.

1) Check Trouble Codes

First of all, use an OBD-II scanner to check the powertrain control module (PCM) and ABS control module fault codes. Illumination of the EPC warning light means that one or more fault codes are saved in the PCM or ABS control module memory.

The transmission control unit, ABS control unit, steering control unit and PCM should be properly scanned for the stored trouble codes. You may also take your vehicle to a professional to have fault codes read, or you can do it at home with an OBD-II scanner.

Read More: Bad PCM Symptoms and Causes

2) Inspect the Brake Light Switch

As we discussed above, the brake light switch is one of the common causes of EPC light illumination. To check the working of this switch, step on the brake pedal when checking your car’s brake lights. If your brake lights don’t turn on, there is a high risk that the brake light switch is not working efficiently.

3) Check Engine Sensors

You should check your sensor data if you use an OBD-II scanner and can’t find a good trouble code to continue troubleshooting. Check the MAP sensor, MAF sensor, and brake pressure sensor reading to make sure they are working efficiently.

Also, check the data of all other engine sensors and the data of the sensors connected to the brake and EPC systems.

4) Talk to a Professional

Without sufficient knowledge and tools, properly diagnosing an EPC system may be tough. So, you should contact a mechanic if you’ve done the basics and still can’t find the root cause of the illuminated EPC light.

FAQ Section

What does the EPC Light mean on a Volkswagen or Audi?

The EPC light is a warning light that specifies an issue with the Electronic Power Control (EPC) system of your vehicle. When the EPC light starts illuminating, it generally indicates a problem with the throttle system of the vehicle.

Can a misfire cause an EPC light?

Yes, the engine misfiring may indirectly illuminate the EPC light. When the engine misfires, the performance of the engine reduces, and the check engine light starts illuminating on the vehicle dashboard. The EPC light may also come on when there is an issue with the engine system.

Why does my EPC light come on when I accelerate?

The Electronic Power Control (EPC) light denotes a problem with the throttle system. The main function of the throttle system is to control the power output of the engine by regulating the amount of fuel or air entering the combustion chamber. The throttle system plays a big role in efficient acceleration, so it makes sense for the light to come on during acceleration.

Can I drive with illuminating EPC Warning Light?

As we discussed above, your EPC light may illuminate for multiple reasons. Driving without knowing why the EPC light is illuminating is dangerous. You shouldn’t drive your vehicle for a long time with this light. You should fix EPC issues immediately. Some vehicle functions may be restricted when the lights are on.

Since the EPC system of your car is connected to the brake system, steering system, and engine. Therefore, a faulty EPC system may badly damage the engine, steering system, or braking system. It may also restrict the functionality of the steering system or brake system, which may lead to serious accidents. So, if you see the EPC light on the vehicle dashboard, get your vehicle to the mechanic immediately.

Problems with the EPC system do not usually harm the vehicle if driven carefully, but in some cases, the problem can be more serious, so it is recommended to have it checked immediately.

What Causes A VW EPC Light to Turn On?

  • Damaged electrical wiring or loose connections of the EPC system issues
  • Bad steering sensor
  • Bad ABS sensor
  • Damaged or faulty throttle body
  • A faulty throttle position sensor
  • Bad Power steering
  • Faulty Brake light switch
  • Bad engine speed sensor
  • Faulty MAF sensor
  • Bad Traction control

Can I ignore the EPC light?

No, you shouldn’t ignore an illuminating EPC light. It indicates an issue with the EPC system. The engine control unit, the steering control unit, and the brake control unit all help to control the functionality of the EPC. Therefore, when your EPC light illuminates on the vehicle dashboard, you should immediately contact a professional mechanic to find the root cause of the problem.

What repairs can fix the EPC Light?

  • Replacing the bad throttle body
  • Replacing the bad ABS sensor
  • Replacing the bad brake pedal switch
  • Replacing the faulty brake pressure sensor
  • Replacing the bad engine sensor
  • Replacing the faulty steering angle sensor
  • Fixing the wiring and loose connection issues

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