ESP BAS Light On? (Common Causes and How to Fix It)
You don’t want to see a warning light flashing on your dashboard when you get behind the wheel to start your car. However, the ESP BAS light is optional on certain vehicle brands.
The ESP BAS light is a very important light for modern vehicles. If the light doesn’t go off, some advanced safety features will be lost. Here we explain what causes the ESP BAS light to come on and how to fix the problem specifically.
What does ESP BAS mean? ESP BAS stands for “Electronic Stability Program” or “Brake Assist System” in your vehicle. If the light comes on, it means there is an underlying problem with one of these systems. Not all vehicles have the ESP BAS light because not all vehicles have one, but it is a common light on Jeeps, Dodges, and Chryslers.
This light can also be found in Mercedes-Benz vehicles, but it is called the “BAS ESP” or “BAS” light instead of the ESP BAS light. ESP BAS consists of two systems: Electronic Stability Program (also known as Electronic Stability Control or ESC) and Brake Assist. To understand exactly how the ESP BAS system works, you need to understand both underlying systems.
The ESP system is similar to traction control, but while traction control helps keep the vehicle going straight, ESP assists the vehicle when cornering. Both systems aim to keep the wheels on the ground and provide good traction, but they operate in different settings.
ESP BAS Light On
BAS works in conjunction with the ABS to improve braking performance in an emergency. The BAS detects when you fully depress the brakes in an emergency and keeps them fully depressed until the ABS intervenes.
How to fix the problem
If your car’s ESP-BAS light has just come on, you’re probably worried about how to turn it off. If you want to know why the light is on, it’s best to rule out simple causes first. For this reason, it’s best to rule out the brake switch first.
How to test the switch:
1. Start the car and press the brake pedal with someone standing behind the car.
2. If the brake lights come on, your brake switch is working.
3. If not, you’ve probably found the problem.
Next, you’ll need to hook up an automotive diagnostic tool so you can check the readings of the various sensors.
1. First, look at the display of the steering angle sensor. While paying attention to the sensor reading, turn the steering wheel and see if the reading changes correctly.
2. If so, the problem is not here. If not, the steering angle sensor may be the culprit.
From there, get the wheel speed sensor readings and drive with a passenger.
1. While you’re driving, have them check the wheel sensor readings to see if there are any that don’t match up with the other values.
2. If so, a faulty wheel speed sensor may be the problem.
Note that with these sensors, it is possible that the problem is not getting a signal from the sensor to the computer. While unlikely, in this case there is a wiring issue that will require troubleshooting.
What if it comes back on after a reset? If the ESP BAS light comes back on immediately after a reset, it is likely that you did not properly diagnose or fix the problem the first time. We know this can be a frustrating situation because you thought the problem was solved, but the light comes back on, but the problem is still there.
Simply resetting the warning light with a diagnostic tool is not the solution. If the root cause is not resolved, the light will come back on when the normal diagnostics are run at startup.
If you have correctly diagnosed and replaced the component, it is more likely that your vehicle has some kind of wiring issue that is preventing the signal from the sensor from reaching the computer.
You will need to start the troubleshooting process again to find out what is going on, or take your car to a professional mechanic to have it repaired.