Modern vehicles have more and more warning lights on their instrument clusters. In this article, you will find a list of the most important security-related lights and what they mean.
ABS Light
Vehicles with ABS (Anti-Lock Brake System) brakes show a yellow light on the dashboard which tells the driver what the system status. This light is commanded by the ABS module and, depending on the vehicle’s make and model, it stays “on” while the engine is off and the ignition key is in the “on” position or stays “on” for a while and, after a system check, the light turns off. What doesn’t vary depending on the vehicle’s make and model is that when the engine is running, the light should stay off. Some ABS modules make the light blink when the driver is pressing the brakes hard and the ABS system is working, but the light goes off right after.
If your ABS light stays on when your engine is running, something in your ABS is not working properly. It’s important to notice that when the ABS light stays “on”, the vehicle is running without the aid of the ABS. The ABS module turns the system off when it detects a failure to avoid dangerous situations. Some of the reasons that can turn your ABS light “on” are:
- Defective wheel speed sensor or wiring: if the ABS control module doesn’t read the speed of any of the wheels, or if the speed of one wheel is significantly different from the speed of the other wheels, it will save a fault code and turn the ABS light “on”. This failure is very common; most of the time it’s solved by replacing the faulty sensor or repairing the wiring that connects the sensor to the module.
- Defective ABS pump: ABS pumps can fail and stop working when the ABS module senses it, turns the system off, saves an error code, and lights the ABS light on the instrument cluster.
- Defective ABS module: sometimes the ABS module itself fails. The ABS light gets lit on the instrument cluster after the ABS computer self-test fails.
ABS is an important safety feature. If your vehicle’s ABS light stays on, you should go to a repair shop as soon as you can. They will plug in a scanner, read the fault code/s from your ABS computer and take care of solving the problem.
ESC/ASR Light
ESC (Electronic Stability Control) and ASR (Anti-Slip Regulation) are features that work with the ABS system and the ECU (Electronic Control Unit) to help the vehicle to stay on the road under hazardous conditions. The ESC uses sensors like the “steering angle sensor” and accelerometers to determine if the vehicle is behaving following the driver’s input (steering wheel, brakes, and gas). Measuring the wheels’ speed individually and the steering angle can help to correct driver errors by locking or unlocking a wheel, reducing the engine power by shutting the throttle body down, etc. The system is great to prevent oversteering and understeering. ASR prevents the vehicle from slipping during hard accelerations or while driving over wet roads. If the ESC or the ASR light stays on, check whether you have deactivated the system by mistake (many vehicles allow drivers to deactivate the system by pressing a special button). If you haven’t, you should take your car to a knowledgeable car repair garage to plug the car into a scanner and check what’s causing the problem.
Airbag Light
The airbag light is a red warning light that lights when something in your vehicle’s airbag system is wrong. There are many reasons that can turn the airbag light on. The system is very complex and the light is triggered as soon as the airbag module senses that something is wrong. Many times the fault can be as simple as a dirty connector, and other times the problem can be much more complex. Airbags and all other elements of the system are very sensitive and should be manipulated by professionals only. If your vehicle is having an airbag problem, go visit a specialized shop as soon as you can.
