What Causes the ABS Light to Illuminate in a Buick Regal?

[Ingrid]

There are multiple scenarios where the ABS light may illuminate, each with distinct causes and solutions as detailed below: Scenario 1: ABS warning light remains constantly lit (most common). Cause 1: The ABS wheel speed sensor's sensing area is contaminated by mud, sludge, or other pollutants, impairing its ability to detect wheel speed signals. This prevents the ABS control module from determining vehicle speed or calculating wheel slip rates, thus disabling proper brake modulation. Solution: Clean 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. Solution: Inspect all wiring connections and secure any loose terminals. Scenario 2: ABS warning light intermittently illuminates but extinguishes during acceleration. Cause: Battery voltage drops below 10.5V when multiple electrical systems are active. The light turns off as engine RPM increases voltage. Possible low voltage supply to ABS system due to poor terminal contact or grounding issues. Solution: Check battery specific gravity, charging system, and power supply components (e.g., voltage relays or loose power connections). Scenario 3: ABS light stays on after engine start until ignition is turned off. Cause: Poor grounding connection at ABS hydraulic valve body; faulty wiring harness connector; ABS control module malfunction. Solution: Loosen and retighten valve body ground screws, clean contact surfaces if necessary; inspect connector gaps; replace ABS or ABS/ASR control module. Scenario 4: ABS warning light activates during high-speed driving. Cause: Significant discrepancy between front and rear wheel speed signals detected by ABS module; incorrect tire or wheel specifications. Solution: Verify proper tire and wheel sizes per specifications (refer to fuel filler door sticker). Scenario 5: Intermittent ABS warning light activation. Cause: Maladjusted brake light switch; internal contact failure in brake lights. Solution: With engine running, fully depress brake pedal while manually pushing switch lever downward, then release pedal to reset; replace brake light switch if needed. Important: When the ABS light is illuminated, discontinue driving immediately. ABS failure compromises anti-lock braking functionality, potentially causing wheel lock-up during emergency stops, resulting in loss of vehicle control and inability to decelerate or steer – presenting significant safety hazards.