Here are the most common reasons:
* Faulty Wheel Speed Sensor: These sensors measure the rotation speed of each wheel. A malfunctioning sensor provides inaccurate data to the ABS module, causing both lights to come on. This is the most frequent cause. Corrosion or damage to the sensor wiring is also possible.
* ABS Module Failure: The ABS module itself might be faulty. This is a more serious and expensive problem, potentially requiring replacement.
* Low Brake Fluid: While less likely to trigger both lights simultaneously, extremely low brake fluid can indicate a leak in the system, which could also affect ABS functionality.
* Faulty Brake Light Switch: A malfunctioning brake light switch can sometimes cause erratic signals to the ABS and StabiliTrak systems.
* Wiring Issues: Damaged or corroded wiring in the ABS system can disrupt signals and cause the lights to illuminate.
* Power Issues: Intermittent power supply problems to the ABS module could also cause the warning lights to appear.
What to do:
1. Check your brake fluid level: This is the easiest and quickest check. Low fluid suggests a leak, which needs immediate attention.
2. Have it professionally diagnosed: Don't ignore these warning lights. Take your Avalanche to a mechanic or an auto parts store that can perform OBD-II diagnostics. The scan tool will read the diagnostic trouble codes (DTCs) stored by the vehicle's computer, pinpointing the exact problem. This is crucial for accurate and cost-effective repair.
Ignoring these lights can lead to reduced braking performance and instability, especially in emergency situations. Get it checked out as soon as possible.
