What Causes the ABS Light to Illuminate in the Emgrand GS?

[McLincoln]

ABS light illumination can occur in various states, each with different causes and solutions, as detailed below: State 1: ABS warning light remains constantly lit (most common). Cause 1: The ABS speed sensor's sensing area is covered by mud, sludge, or other contaminants, affecting its ability to detect the corresponding speed signal. This prevents the ABS computer from determining the vehicle's speed or the wheel's slip rate, thus failing to issue appropriate commands to adjust braking. Solution: Clean the contaminants from the 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 in the ABS relay can lead to signal issues and system failure. Solution: Inspect wire connections and reconnect any loose parts. State 2: ABS warning light intermittently illuminates but turns off during acceleration. Cause: When multiple vehicle electrical components are in use, the battery voltage may drop below 10.5V. As 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, and examine the power supply (e.g., voltage relay or poor power contact). State 3: ABS warning light remains lit after engine start and only turns off when the engine is turned off (IGFF). Cause: Poor grounding contact in the ABS hydraulic valve body, loose wiring connections in the valve body, or ABS computer malfunction. Solution: Loosen and retighten the grounding screw on the hydraulic valve body, clean contact surfaces if necessary, check for enlarged connector 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 rear and front wheel speed signals during high-speed driving, or 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 or internal contact issues in 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 pedal to reset its position. Replace the brake light switch if necessary. If the ABS warning light is on, it is advisable not to continue driving. An illuminated ABS light indicates a malfunction in the anti-lock braking system, which can lead to wheel lock-up during emergency braking, causing loss of control and skidding. This poses significant safety risks as it may prevent the driver from slowing down or adjusting the vehicle's trajectory.