What Causes the ABS and Anti-Skid Warning Lights to Illuminate in a Nissan Teana?

[LaJasmine]

ABS warning lights can illuminate in various states, each indicating different fault causes and requiring distinct solutions, as detailed below: State 1: ABS warning light remains constantly illuminated (most common). Cause 1: The ABS wheel 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 control unit from determining the vehicle's speed and wheel slip rate, thus failing to issue appropriate commands to regulate braking. Solution: Clean the contaminants from the wheel speed sensor and adjust the gap between the sensor and the signal ring to restore normal function. Cause 2: Poor signal transmission due to loose connections in the system wiring or poor contact in the ABS relay, leading to system malfunction. Solution: Inspect wiring connections and reconnect any loose parts. 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. The ABS warning light turns off as the engine speed increases and voltage rises. This may also occur due to insufficient power supply voltage to the ABS system, such as 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 illuminated after engine start and only turns off when the engine is turned off (IGFF). Cause: Poor grounding contact in the ABS hydraulic valve body wiring; loose connections in the ABS hydraulic valve body wiring harness; or ABS control unit malfunction. Solution: Loosen and retighten the grounding screw on the hydraulic valve body, cleaning the contact surface if necessary. Check for enlarged gaps in connectors. Replace the ABS or ABS/ASR control unit if needed. State 4: ABS warning light illuminates during high-speed driving. Cause: The ABS control unit detects a significant discrepancy between rear and front wheel speed signals during high-speed driving. This may also result from incorrect tire or wheel rim specifications. Solution: Refer to the vehicle's specified tire and wheel rim dimensions, 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 in the brake light. Solution: With the engine running, press the brake pedal and manually push the brake switch linkage fully downward, then release the pedal to complete self-positioning. Replace the brake light switch if necessary. If the ABS warning light is illuminated, it is advisable to avoid continued driving. An illuminated ABS light indicates a malfunction in the anti-lock braking system, which may cause wheel lock-up during emergency braking, leading to loss of vehicle control and skidding. This poses significant safety risks as the driver may be unable to decelerate or adjust the vehicle's trajectory.