EPC light: What is it and how does EPC work?

November 7, 2022

What is EPC?

EPC is a computer, connected to a whole bunch of systems in the car. Thus, it is connected to the traction control, cruise control, accelerator pedal, gearbox but also, for example, the brake lights. When a failure occurs in this chain, the EPC light comes on. However, many cars do not have an EPC light, but they do have an EPC system. All Volkswagen Group cars do have an EPC light on board, because the Volkswagen Auto Group (VAG) invented the EPC system.

Lit EPC light

The EPC indicates a fault when one of the sensors in the powertrain components gives an error message. The light will come on and it is then wise to pull over the car in the nearest parking lot. Then turn off the engine to prevent any (further) damage. Despite the fact that in most cases the engine just keeps working, it is still wise to stop. Have a mechanic read the car first, before driving again.

Jumper cables

A common time when the EPC malfunctions is after providing starting assistance. This is necessary when your car’s battery is dead and is done using jumper cables. When the car is helped with the jumper cables, there is peak voltage. At that point, there is a good chance that the electronics will be confused by this high voltage. The EPC light then comes on. You can avoid this by turning on as many major power consumers as possible immediately after starting the car. Some examples are the air conditioner, rear window heater and high beam.

Other lights

The EPC is an important system, controlling a lot of driveline functions. Therefore, when the EPC light comes on, other lights often do as well. Examples include the ESP light or the engine management light. The EPC controls all these functions and therefore it is interrelated. So just one simple malfunction can cause a whole light show in your instrument cluster.