What does the yellow ABS light on the car dashboard mean?

[McMorgan]

ABS light can indicate various conditions, each with different causes and solutions, as detailed below: Condition 1: ABS warning light stays on (most common). Cause 1: The ABS speed sensor's sensing part is covered by dirt, mud, or other contaminants, affecting its ability to detect the vehicle's speed signal. This prevents the ABS computer from determining the speed and wheel slip rate, thus failing to issue appropriate commands to adjust braking. Solution: Clean the dirt from the speed sensor and adjust the gap between the sensor and the signal ring to restore normal function. Cause 2: Loose connections in the system wiring or poor contact in the ABS relay can cause signal issues, leading to system failure. Solution: Check the wiring connections and reconnect any loose parts. Condition 2: ABS warning light intermittently turns on but turns off when accelerating. Cause: When multiple electrical devices are in use, the battery voltage may drop below 10.5V. As the engine speed increases, the voltage rises, and the ABS light turns off. This can also occur if the ABS system's power supply voltage is too low due to poor contact or grounding issues. Solution: Check the battery's specific gravity, charging system, and power supply (e.g., voltage relay or poor power contact). Condition 3: ABS warning light stays on after engine start and only turns off when the engine is turned off (IGFF). Cause: Poor grounding contact in the ABS hydraulic valve body, loose wiring connections in the ABS hydraulic valve body, or ABS computer malfunction. Solution: Loosen and retighten the grounding screw of the hydraulic valve body, clean the contact surface if necessary, check for enlarged gaps in the connector, or replace the ABS or ABS/ASR computer. Condition 4: ABS warning light turns on during high-speed driving. Cause: The ABS computer detects a significant difference between the rear and front wheel speeds. This may also occur due to incorrect tire or wheel rim specifications. Solution: Refer to the vehicle's tire and wheel rim specifications, as indicated on the fuel cap label. Condition 5: ABS warning light intermittently turns on. Cause: Improper adjustment of the brake light switch or poor internal contact in the brake light. Solution: With the engine running, press the brake pedal and push the brake switch linkage down with your finger, then release the pedal to complete self-positioning. Alternatively, replace the brake light switch. If the ABS warning light is on, it is advisable not to continue driving. The illuminated ABS light indicates a malfunction in the vehicle's anti-lock braking system. During emergency braking, locked wheels can cause the vehicle to skid uncontrollably, making it difficult for the driver to slow down or adjust the vehicle's path, posing significant safety risks.