What Causes the ABS Light to Illuminate in Rainy Weather?

[McAlivia]

There are multiple scenarios where the ABS light may illuminate, with different causes and solutions for each condition. The details are as follows: Condition 1: ABS warning light remains constantly lit (most common). Cause 1: The ABS wheel speed sensor's detection area is covered by mud, sludge, or other contaminants, affecting its ability to read speed signals. This prevents the ABS control unit from determining vehicle speed or wheel slip rates, thus failing to issue appropriate braking commands. Solution: Clean debris from the wheel speed sensor and adjust its clearance with the tone ring to restore normal function. Cause 2: Loose wiring connections or poor contact in ABS relays causing signal interference and system malfunction. Solution: Inspect wiring connections and re-secure any loose terminals. Condition 2: ABS warning light intermittently illuminates but turns off during acceleration. Cause: Battery voltage drops below 10.5V when multiple electrical components are in use. The light extinguishes when engine RPM increases voltage. Possible low voltage supply to ABS system due to poor terminal contact or grounding issues. Solution: Check battery specific gravity; inspect charging system; examine power supply components (e.g., voltage relays or loose power connections). Condition 3: ABS light stays on after engine start until ignition is turned off. Cause: Poor grounding connection at ABS hydraulic valve block; faulty wiring harness connector; or ABS control module failure. Solution: Loosen and retighten valve block ground screws, cleaning contact surfaces if necessary; check for connector pin gap widening; replace ABS or ABS/ASR control module. Condition 4: ABS warning light activates during high-speed driving. Cause: ABS control module detects significant discrepancy between front and rear wheel speeds; incorrect tire or wheel rim specifications. Solution: Verify proper tire and rim specifications as indicated on fuel filler door placard. Condition 5: Intermittent ABS warning light activation. Cause: Maladjusted brake light switch or internal contact failure. Solution: With engine running, depress brake pedal while manually pushing switch linkage downward to reset position; replace brake light switch if needed. When the ABS warning light is illuminated, continued driving is not recommended. An active ABS fault means the anti-lock braking system is compromised. During emergency braking, wheel lock-up may occur, causing loss of vehicle control and inability to decelerate or adjust trajectory, posing significant safety risks.