What does ABS on the car dashboard mean?

[LaRowan]

ABS light can illuminate in various states, with different causes and solutions for each state, as detailed below: State 1: ABS warning light stays on (most common). Cause 1: The ABS wheel speed sensor's sensing part is covered by dirt, mud, or other contaminants, affecting its ability to detect the corresponding speed signal. This prevents the ABS computer from determining the vehicle speed and wheel slip rate, thus failing to issue appropriate commands to adjust braking. Solution: Clean the dirt from the wheel speed sensor and adjust the gap between the sensor and the signal ring to restore normal function. Cause 2: Loose connections between system wires or poor contact of the ABS relay can lead to signal issues and system failure. Solution: Check wire connections and reconnect any loose parts. State 2: ABS warning light intermittently illuminates but turns off when accelerating. Cause: When multiple vehicle electrical devices are in use, the battery voltage may drop below 10.5V. As the engine speed increases and voltage rises, the ABS light turns off. This can also occur if the ABS system's power supply voltage is too low due to poor wire contact or grounding issues. Solution: Check the battery's specific gravity; inspect the charging system; examine the power supply (e.g., voltage relay or poor power contact). State 3: ABS warning light stays on after engine start but turns off when the engine is turned off (IGFF). Cause: Poor grounding contact of the ABS hydraulic valve body; poor contact at the ABS hydraulic valve body wire 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. State 4: ABS warning light illuminates during high-speed driving. Cause: At high speeds, the ABS computer detects a significant discrepancy between rear and front wheel speed signals; 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. State 5: ABS warning light intermittently illuminates. Cause: Improper adjustment of the brake light switch; poor internal contact of the brake light. Solution: With the engine running, press the brake pedal, push the brake switch linkage down fully with a finger, then release the brake pedal to complete self-setting; replace the brake light switch. If the ABS warning light is on, it is advised not to continue driving, as this indicates a malfunction 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 path, posing significant safety risks.