What does the car ABS system mean?

[CamilaAnn]

When the car displays ABS, it means there is a malfunction in the vehicle's Anti-lock Braking System. During emergency braking, if the wheels lock up, the vehicle may lose control and skid, making it difficult for the driver to slow down or adjust the vehicle's trajectory, posing a significant safety hazard. There are several conditions in which the ABS warning light may illuminate, 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 the sensor's ability to detect the corresponding speed signal. This prevents the ABS computer from determining the vehicle speed and the wheel's 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: Loose connections in the system wiring or poor contact in the ABS relay can lead to signal issues, causing system failure. Solution: Check the wiring connections and reconnect any loose parts. Condition 2: ABS warning light intermittently illuminates but turns off when accelerating. Cause: When multiple vehicle electrical components are in use, the battery voltage may drop below 10.5V. As the engine speed increases and voltage rises, the ABS warning light turns off. This can also occur if the ABS system's power supply voltage is too low 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). Condition 3: ABS warning light stays on after engine startup and only turns off when the engine is turned off (IGFF). Cause: Poor grounding connection of the ABS hydraulic valve body; loose wiring connections in the ABS hydraulic valve body; or ABS computer malfunction. Solution: Loosen and then retighten the grounding screw of the hydraulic valve body, 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 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, usually listed on the sticker near the fuel tank cap. Condition 5: ABS warning light intermittently illuminates. Cause: Improper adjustment of the brake light switch; poor internal contact in the brake light. Solution: Start the engine, press the brake pedal, and use your finger to push the brake switch linkage all the way down. Then release the brake pedal to complete the self-setting position. Replace the brake light switch if necessary.