What causes both the ABS and tire pressure warning lights to illuminate simultaneously?

[Gideon]

ABS warning light can indicate various conditions, each with different causes and solutions, as detailed below: Condition 1: ABS warning light remains constantly illuminated (most common). Cause 1: The ABS wheel speed sensor's detection area is contaminated by mud, sludge, or other pollutants, affecting its ability to read wheel speed signals. This prevents the ABS control unit from determining vehicle speed or calculating wheel slip rates, thus failing to issue proper braking commands. 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 ABS relay contact causing signal interference. Solution: Inspect all wiring connections and 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 speed increases voltage. Possible low voltage supply to ABS system due to poor connections or grounding issues. Solution: Check battery specific gravity, charging system, and power supply connections (including voltage relays). Condition 3: ABS warning light stays on after engine start until ignition is turned off. Cause: Poor grounding of ABS hydraulic valve body; faulty wiring connections; or ABS control module failure. Solution: Loosen and retighten valve body ground screws (clean contact surfaces if necessary); inspect connector gaps; replace ABS/ASR control module if needed. Condition 4: ABS warning light activates during high-speed driving. Cause: Significant discrepancy between front and rear wheel speed readings; incorrect tire or wheel rim specifications. Solution: Verify proper tire and wheel rim specifications as indicated on the fuel filler door placard. Condition 5: ABS warning light flashes intermittently. Cause: Improper brake light switch adjustment; internal switch contact failure. Solution: With engine running, fully depress brake pedal while manually pushing switch lever downward to reset position; replace brake light switch if necessary. Important: When the ABS warning light is illuminated, discontinue driving immediately. ABS failure compromises wheel anti-lock braking functionality, potentially causing wheel lock-up during emergency braking, resulting in loss of vehicle control and trajectory adjustment capability, posing significant safety risks.