What does the ABS yellow light on the dashboard mean?

[TannerRose]

When the car displays the ABS light, it indicates a malfunction in the vehicle's Anti-lock Braking System. If the wheels lock up during emergency braking, the vehicle may lose control and skid, making it difficult for the driver to slow down or adjust the vehicle's trajectory, which poses significant safety risks. There are several conditions under which the ABS light may illuminate, each with different causes and solutions, as detailed below: Condition 1: ABS warning light stays on continuously (most common). Cause 1: The ABS speed sensor's sensing area 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's speed and the wheel slip rate, thus failing to issue appropriate commands to regulate braking. Solution: Clean the dirt from the speed sensor and adjust the gap between the speed sensor and the signal ring to restore normal function. Cause 2: Poor signal quality due to loose connections in the system wiring or poor contact in the ABS relay, leading to system failure. Solution: Check the wiring connections and reconnect any loose parts. Condition 2: ABS warning light intermittently illuminates, turning off during acceleration. Cause: When multiple vehicle electrical devices are in use, the battery voltage may drop below 10.5V. As the engine speed increases, the voltage rises, and the ABS warning light turns off. This can also occur if the ABS system's power supply voltage is too low, such as 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 power contact issues). Condition 3: ABS warning light stays on after engine start, only turning off when the engine is turned off (IGFF). Cause: Poor grounding contact in the ABS hydraulic valve body, poor contact in the ABS hydraulic valve body wiring connector, or ABS computer malfunction. Solution: Loosen the grounding screw on 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. Condition 4: ABS warning light illuminates during high-speed driving. Cause: At high speeds, the ABS computer detects a significant discrepancy between the rear wheel speed and front wheel speed signals. 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 label near the fuel tank cap. Condition 5: ABS warning light intermittently illuminates. Cause: Improper adjustment of the brake light switch or poor internal contact in the brake light. Solution: Start the engine, press the brake pedal, and use a finger to push the brake switch linkage all the way down. Then release the brake pedal to complete the self-setting process. Replace the brake light switch if necessary.