In a few words:
The EPC warning light comes on to indicate that there is a problem with the electronic system that controls the engine. The only way to identify the problem quickly is by scanning your car’s computer. You should take into account that the problem may go from a burnt out headlight bulb to throttle failure. For this reason, trying to find the problem any other way may be a troublesome task.
The EPC (Electronic Power Control) can be found in cars that accelerate thanks to a sensor in the throttle. In these cases, the throttle will have a TPS (Throttle Position Sensor) and an actuator (electric engine), that is to say, there are no mechanical connections between the throttle and the engine of the car. As a consequence, the EPC is in charge of the regulation of the throttle body according, mainly, to a signal sent by the throttle sensor. This is how fuel consumption and emissions are decreased.
This system is also powered by the signals of auxiliary sensors such as the crankshaft position sensor (CKP), the manifold absolute pressure (MAP) sensor, the mass air flow (MAF) sensor and the knock sensor, among others.
This warning light will turn on briefly when you turn the ignition key and then it will turn off, which indicates that the light works properly. If the warning light is still on even after the car has been started or if it comes on while you are driving, that means that there is a problem with the acceleration system. In addition, your car may jerk, have combustion issues or loss of power.
Taking into account that the electronic acceleration system interacts with other systems of the car, it is possible that other warning lights will come on on the dashboard, such as the check engine light or the electronic stability control light, which appear below:
To protect the engine, the car’s computer may limit the acceleration of the car. Because of this, you will not be able to accelerate. The severity of the problem and the accompanying symptoms may vary significantly, which is why it is important to scan the car as soon as possible to know its error codes and begin the reparation process.
Common causes for this EPC light to come on:
The last two items happen because of the way the Engine Control Unit (the main computer) is programmed. Modern cars do not have this failure since they have better systems installed to their computers.