If you drive one of the Volkswagen group cars, you may, sooner or later, encounter the EPC light coming up on the dashboard.
The truth is that, in most situations, the driver doesn’t know the meaning of this warning light nor what problem may have caused it.
This article will, hopefully, help you understand the whole topic better or even give you a heads-up on how to solve it.
MEANING OF THE EPC LIGHT
EPC stands for Electronic Power Control and is a dashboard warning light that indicates mainly problems with the throttle system (throttle pedal, throttle body, ECU, and else).
But besides this, it may also indicate problems with other systems that we shall mention in the next part of the article.
As mentioned, this warning light is characteristic of Volkswagen group cars.
WHAT CAUSES THE PROBLEM?
The most common reason for the EPC light problem is:
- Throttle body
- Throttle pedal
- Electric connections within this system
Besides these, there might also be problems with the :
- Engine speed sensor
- Crankshaft sensor
- Camshaft position sensor
- MAF or mass airflow sensor
- Brake light switch
- Traction control system
- Cruise control
- Vehicle stability control
- ECU problems
- Fuel injection
- Emission system
As you can see, a pretty wide variety of reasons but the first group is the most common and should be checked first.
WHAT HAPPENS WHEN THE EPC LIGHT COMES ON?
It all depends on what has malfunctioned.
The problem might manifest itself with just the warning light coming up, without any major trouble regarding driving. For instance, this is the case when the brake light switch is the problem,
On the other hand, you might experience a lack of engine power (like when you have a faulty sensor, a fault in the fuel injection system, or else). In these cases, the car will go into the so-called limp mode making driving possible but with reduced engine power.
But there might be more serious and dramatic symptoms. For instance (and from my own experience), when the throttle body is dirty and has a grime build-up, the car may start to violently jolt. After this, the engine may cut off completely.
When this happens, usually both the EPC and check engine light come up on the dashboard.
HOW TO FIX THE EPC LIGHT?
This again depends on what the problem is.
The best way to start the repair is to connect an OBD tool and try to get a trouble code. But, besides this, some experience and additional inquiry do come in handy.
I’m mentioning this as sometimes the trouble code might set you on a wild goose chase that can cost time, money, and nerves.
When you conclude what the problem is, here’s some information of what lays ahead of you:
Bad sensors or brake light switches
This is a relatively easy fix. Problems may appear when trying to reach the sensor or switch. Sometimes you need to remove plastic trim panels or even raise the car in order to access them. Also, making a proper diagnosis of the problem is crucial in order to make sure that the sensor or switch is the actual problem.
Bad throttle body problem
The solution may span from cleaning to completely replacing the throttle body, all depending on what’s the actual problem. In most cases, when there’s a grime build-up, cleaning is the solution.
But if there is physical damage (especially to the electric mechanism that moves the butterfly valve), then you’ll have to replace this pricey part.
Also, you can read about the most common symptoms of a bad throttle body by clicking here.
Faulty throttle pedal
When this is the cause of the EPC light problem, replacing it is the best solution.
Problems with electric connections
The answer to this problem is the cleaning and tightening of the connections. In worst cases, the connectors might have to be completely replaced.
ECU problems, fuel injection, and emission system problems
In most cases, these are the most complicated, time-consuming, and expensive repairs. Here, the biggest issue is pinpointing the reason and finding where the problem is.
The EPC light problem is not that common as, perhaps, the check engine light is.
But unlike the check engine light problem(which drivers tend to ignore or postpone), the moment the EPC light comes up, you should try to find out what’s wrong.
Mainly because it signals a malfunction in one or more of the systems that are vital to the proper engine functioning.
Lots of time you’ll be forced to react as the engine will cease to run normally.
All of this means that If you ignore it, you may find yourself in a tight spot. Because of negligence, you might be left stranded on the road or even cause damage to the engine.
In the end, I must mention once more: in the case of the EPC light, it’s crucial to find the exact reason for the problem before starting the repair. Otherwise, you might end up spending a lot of money and time on parts and unneeded repairs only to solve nothing.
Written by: Sibin Spasojevic
Former car technician, life-long car and DIY enthusiast, author for Despairrepair.com