With every passing year, the electronic controls for automotive systems are getting more and more sophisticated. The transmission, engine systems, braking, and even the suspension are all governed by sensors and processors, enhancing reliability and safety but also setting the bar a lot higher for service.

What Is the EPC Light on a Volkswagen?

The Electronic Power Control (EPC) warning light is an indication that there's a problem with your vehicle's throttle system (which could include the accelerator pedal, fuel injection throttle body, traction control or cruise control). It can also point to other problems as well, though. We're going to explain what the Volkswagen EPC light indicates, and what to do if it's illuminated.

Can the EPC Warning Light Cause a Loss of Power?

Since the 90s, many engine management systems have included what's called a "limp-in mode" or "limp-home mode." Limp-in mode restricts the vehicle's speed and might not let the automatic transmission shift out of second gear. It kicks in when the vehicle's drivetrain computer registers a serious problem and is designed to allow you to get to the dealership without causing any further damage to the system that's having a problem.

What Can Cause the EPC Light To Come On?

Like the Check Engine light on other makes, a Jetta EPC light, VW Beetle EPC light or Audi EPC light can be a generic warning. When the drivetrain computer recognizes a reading that's out of normal spec for a system, it's stored in the computer as a trouble code, or EPC code in the case of Volkswagen vehicles. In this instance, the EPC sensor has given the computer information that caused the vehicle to be put into limp-in mode. Potential issues can include:

  • Malfunctions with fuel metering, timing or emissions systems
  • Engine speed sensor failure
  • Problems with other sensors such as the crank or cam position sensor, mass airflow sensor, even the brake light switch
  • Traction control problems
  • Vehicle stability control problems
  • Cruise control issues
  • Throttle pedal issues

Years ago, the accelerator and cruise control were connected to the throttle via cables. Today's systems are called "drive-by-wire," a term that, paradoxically, means there are no cables anymore. The gas pedal and throttle "talk to each other" wirelessly, and their status and positions are reported to the drivetrain computer wirelessly and in real time via sensors.

Is It Safe To Drive With the EPC Light On?

Quick answer: no. The EPC light could be an indicator of a wide range of problems, some relatively minor and some quite a bit 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.

In addition, some Volkswagen vehicles that are equipped with an Electronic Stability Control (ESP) system may shut down entirely when the EPC program detects problems with the EPC management system. So if you're searching for new Jetta cars for sale, it's important to take note of this.

This is important to remember: your vehicle might still be drivable (somewhat) in limp-home mode, but it's limited in speed and acceleration to prevent serious damage to drivetrain components. It's what's known as "error-tolerant design," and is intended to prevent the user from being able to unwittingly do too much damage. Especially when we're talking about the cooling system, emissions, transmission and other major systems, one problem can quickly multiply and turn into a series of problems if you don't get the initial problem addressed right away.

Can a Dead Battery Cause the EPC Light To Come On?

Yes. Your vehicle's systems and sensors rely on a baseline voltage (which can vary depending on the sensor) to be able to work properly. Any kind of a dip in that baseline voltage, from a dead battery, failing alternator or even a bad or loose battery cable, can be enough to cause drivability problems or just shut the vehicle down completely and trigger the EPC light.

How To Reset the EPC Light?

Various generations of Volkswagen vehicles have various procedures for resetting the EPC light. We'd have to advise against doing this unless the problem that triggered the EPC light has been diagnosed and repaired first.

Whether it's a Volkswagen EPC light or a Check Engine light on some other make, these systems are designed to take a lot of the guesswork and deduction out of diagnosis and repair for technicians. The tech has tools that can quickly access the code that caused the EPC light to come on in the first place; after interpreting the code and doing a little reading between the lines, the tech can then track down the part or system that's at fault and effect a repair.

It's important to trust your car to VW factory-trained techs like the ones at Gunther VW Delray's service department (where you can also find killer Jetta lease deals) -- we can zero in on whatever made that Volkswagen EPC light come on, get it taken care of and get you safely back on your way again.