If the ABS warning light is on, it is not recommended to continue driving. This is because the illuminated ABS light indicates a malfunction in the vehicle's anti-lock braking system. During emergency braking, if the wheels lock up, the vehicle may skid uncontrollably, making it difficult for the driver to slow down or adjust the vehicle's trajectory, posing significant safety risks. There are various states in which the ABS light may illuminate, each with different causes and solutions, as detailed below: State 1: ABS warning light remains constantly on (most common). Cause 1: The ABS speed sensor's sensing area 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's 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: Poor signal due to loose system wiring connections or faulty ABS relay contacts, leading to system malfunction. Solution: Check wiring connections and re-secure any loose connections. State 2: ABS warning light intermittently illuminates but turns off during acceleration. 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 light to turn off. Alternatively, the ABS system's power supply voltage may be 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). State 3: ABS warning light remains on after engine start and only turns off when the engine is turned off (IGFF). Cause: Poor grounding connection of the ABS hydraulic valve body; loose wiring connections at the ABS hydraulic valve body; ABS computer malfunction. Solution: Loosen and then re-tighten the grounding screw of the hydraulic valve body, cleaning the contact surface if necessary. Check for enlarged terminal gaps and replace the ABS or ABS/ASR computer if needed. State 4: ABS warning light illuminates during high-speed driving. Cause: The ABS computer detects a significant discrepancy between the rear and front wheel speed signals during high-speed driving. Incorrect tire or wheel rim specifications may also be the cause. Solution: Refer to the vehicle's tire and wheel rim specifications, typically listed on the fuel tank cap sticker. State 5: ABS warning light intermittently illuminates. Cause: Improper adjustment of the brake light switch; poor internal contact in the brake light. Solution: With the engine running, press the brake pedal and manually push the brake switch linkage down to its limit, then release the pedal to complete self-adjustment. Replace the brake light switch if necessary.
