What to Do When the ABS Light in the Car Comes On?

[SanNathan]

There are various states when the ABS light comes on, with different causes and solutions for each state. The details are as follows: State 1: The ABS warning light stays on constantly (most common). Cause 1: The ABS speed sensor's sensing part is covered by dirt, mud, or other contaminants, affecting the sensor's ability to detect the corresponding speed signal. This prevents the ABS computer from determining the vehicle speed and the wheel slip rate, thus failing to issue appropriate commands to regulate braking. Solution: Clean the dirt off the speed sensor and adjust the gap between the speed sensor and the signal ring to restore normal function. Cause 2: Poor signal due to loose connections between system lines or poor contact of the ABS relay, leading to system failure. Solution: Check the line connections and reconnect any loose parts. State 2: The ABS warning light intermittently comes on but turns off when accelerating. Cause: When multiple vehicle electrical devices are in use, the battery voltage drops below 10.5V. As the engine speed increases, the voltage rises, causing the ABS indicator light to turn off. The ABS system's power supply voltage is too low, possibly due to poor terminal contact or grounding issues. Solution: Check the battery's specific gravity, inspect the charging system, and examine the power supply (e.g., voltage relay or poor power contact). State 3: The ABS warning light stays on after the engine starts and only turns off when the engine is turned off (IGFF). Cause: Poor grounding contact of the ABS hydraulic valve body; poor contact of the ABS hydraulic valve body's wiring connector; ABS computer malfunction. Solution: Loosen the grounding screw of the hydraulic valve body, then retighten it, cleaning the contact surface if necessary. Check if the connector gap has widened; replace the ABS or ABS/ASR computer if needed. State 4: The ABS warning light comes on during high-speed driving. Cause: At high speeds, the ABS computer detects a significant difference between the rear and front wheel speed signals. Incorrect tire or wheel rim specifications may also be the cause. Solution: Refer to the vehicle's tire and wheel rim specifications, as indicated on the label near the fuel tank cap. State 5: The ABS warning light intermittently comes on. Cause: Improper adjustment of the brake light switch; poor internal contact of the brake light. Solution: With the engine running, press the brake pedal and use a finger to push the brake switch linkage down fully, then release the brake pedal to complete the self-setting position. Replace the brake light switch if necessary. If the ABS warning light comes on, it is advisable not to continue driving. An illuminated ABS light indicates a fault in the vehicle's anti-lock braking system. During emergency braking, if the wheels lock up, the vehicle may skid uncontrollably, preventing the driver from slowing down or adjusting the vehicle's trajectory, posing significant safety risks.