Dashboard lights are called “telltale lights” because they give the driver an idea about what’s wrong with the vehicle. If you own a Volkswagen, Audi, or Porsche, it probably has an electric power control (EPC) warning light. Find out what this light means, its causes, and what to do once it turns on.
The EPC light is exclusive to vehicles under the Volkswagen Audi Group (VAG).
What does the EPC Light mean?
EPC stands for Electronic Power Control, and when this light illuminates on your vehicle’s dash, it’s warning you that your vehicle’s computer-controlled systems or sensors are malfunctioning. It monitors the vehicle’s throttle and ignition as well as its electronic stability and cruise control.
When the ignition is switched on, the (ECM) checks the electronic throttle control system for circuit integrity and communications. During this test, the instrument cluster EPC warning light is illuminated.
If no malfunction in the electronic throttle control system is detected, the EPC warning light is extinguished immediately after the engine starts.
In the event of a malfunction while the engine is running, the ECM will activate the EPC warning light and a diagnostic trouble code will be stored in the ECM memory. The code will depend on the issue that was detected.
Depending on the problem, other warning lights can illuminate at the same time as the EPC, like the check engine light, anti-lock braking system light, and electric power steering lights.
The EPC could also put the vehicle in “limp mode” to protect the engine from further damage. When this mode is activated, less crucial systems like the air conditioning system will function less. It also reduces the engine’s power.
What an illuminated EPC warning light means and operates might vary depending on the vehicle. For example, the electronic stability control (ESP) system might shut down entirely on some Volkswagen vehicles when the EPC program detects something is wrong with the EPC management system.
What Happens When an EPC Light Turns On?
Every year, automakers design incredibly sophisticated electric controls and systems. While these innovations enhance reliability and safety, they also increase the number of vehicle components that rely on a computerized system.
If you drive a VW trim or even a recent Audi model, your vehicle’s powertrain, braking system, or even suspension are likely all governed by sensors and processors that need highly trained professionals for repairs.
Some drivers report that their EPC light blinks or flashes, while others say that it stays on indefinitely. Occasionally, customers mention that their vehicle’s EPC alert lights up when they accelerate between gears.
No matter which make or model you drive or how often your EPC light flashes or shines, the presence of this warning on your dash means that an internal system needs assistance to function properly – but which system is at fault?
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.
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.
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.
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.
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.
Can I Drive if the EPC Dashboard Warning Light Comes On?
In most cases, it is ok to drive for a short amount of time after the EPC light comes on. However, it is best to get your vehicle to the closest VW service center, such as Volkswagen of Des Moines, because the problem could be significant.
Here are just a few of the issues that could be indicated by the EPC dashboard warning light:
- Engine Speed Sensor Malfunction
- Brake Light Switch Malfunction
- Mass Air Flow Sensor Malfunction
- Problem with the Cruise Control
- Problem with the Throttle System
When the EPC VW light is on, it could cause your vehicle to go into “limp mode.” When this happens, the functions of the engine control unit will be limited.
This is just one of the many reasons why it is important not just to know how to fix the EPC light on VW models, but to have the problem addressed by a professional.
FAQs.
What would cause the EPC light to come on?
Your EPC light is a warning that one or more computer-controlled systems in your car have malfunctioned or failed. These systems can range in severity and purpose greatly. It may be your cruise control system that has stopped working, or it may be essential engine systems like the crank position sensor.
Is it OK to drive with EPC light on?
Quick answer: No. The EPC light could indicate a wide range of problems, some relatively minor and some more serious. If your vehicle has an illuminated EPC light and is in limp-in mode, you need to take it to a dealer for diagnosis and repair as soon as you can.
How do I fix my EPC?
If you want to fix the EPC light yourself, you can try the following: first, start the car normally. Then, start the car for the second time and push the accelerator pedal to the floor when the engine starts. In some cases, this works. It is also a good idea to check the electrical connections on the throttle body.
What does EPC lighting mean?
The VW Electronic Power Control (EPC) light is a dashboard indicator that points to issues with the vehicle’s throttle system. It can also indicate any number of underlying issues, including problems with the throttle pedal, throttle body, traction control, or cruise control unit.
Can low oil cause EPC?
Yes, low oil can cause your Volkswagen EPC light to illuminate because low oil levels can quickly cause severe engine damage.
Is EPC light expensive to fix?
Of all the possible maintenance and repair tasks a driver can avoid, the ones related to the EPC warning light are among the most costly. On average, fuel injection throttle body repair runs between $200 and $500.