Why does my car show VSC, TRC ABS lights?

Thursday July 09 2020

Hello Paul, when I drive my Toyota RAV4, the above warning lights appear on the dashboard plus the brake warning light. Before the lights come on, the brake pedal rumbles. What is the cause and how can it be fixed? Christine.

Hello Christine, there is a fault with your Toyota’s Anti-lock braking system (ABS). You need a computer diagnosis to establish what has caused the fault. The fault lights on your dashboard stand for TRC - Traction control; VSC - Vehicle Stability Control; ABS – Anti-lock brake system.

These safety functions are designed to passively assist a driver to maintain vehicle stability and traction by preventing skidding when you accelerate hard or brake on slippery surfaces when driving.

TRC, VSC uses the engine throttle and ABS system’s software and hardware (ABS modulator or pump, ABS/TRC computor, ABS Relay, Brake hydraulic system and wheel speed sensors) to detect loss of traction on slippery conditions and prevent dangerous skidding and loss of control.

This is done by reducing engine power as well as selectively applying brakes to match wheel speeds.
When any of the components mentioned above breaks down, the ABS system will fail to work normally, hence the fault lights.

This can lead to a malfunctioning of the brakes (premature or continuous deployment of the anti-skid facility even when you brake on hard surface where it is not required. Failure of the ABS/TRC/VSC system also takes away the benefit of these autonomous safety features designed to passively prevent an accident when you skid while driving fast through corners on wet roads.


Ordinarily, the brake pedal should rumble only when you brake hard on a wet or dry slippery surface, a situation which calls for autonomous deployment of the ABS. However erratic or continuous deployment of the ABS, even on dry non-slippery surfaces confirms that the system is faulty. Find a qualified garage to attend to this important safety feature as soon as possible.