What causes the ABS light to come on in a Polo car?

[BlakelyDella]

ABS light can illuminate in various states, with different causes and solutions for each state. Details are as follows: State 1: ABS warning light remains constantly on (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 module from determining the vehicle speed and wheel slip rate, thus failing to issue appropriate commands to regulate braking. Solution: Clean the dirt from the wheel speed sensor and adjust the gap between the sensor and the tone ring to restore normal function. Cause 2: Loose connections between system circuits or poor contact in ABS relays causing signal issues that lead to system failure. Solution: Check all wiring connections and reconnect any loose parts. State 2: ABS warning light intermittently illuminates but turns off during acceleration. Cause: When multiple electrical devices are in use, battery voltage drops below 10.5V. As engine speed increases and voltage rises, the ABS light turns off. This may also occur due to insufficient power supply voltage to the ABS system, such as poor terminal contact or grounding issues. Solution: Check battery specific gravity; inspect charging system; examine power supply components (e.g., voltage relay or poor power contact). State 3: ABS warning light remains on after engine start until engine IGFF turns it off. Cause: Poor grounding contact in ABS hydraulic valve body; poor electrical connector contact in ABS hydraulic valve body; ABS computer malfunction. Solution: Loosen then retighten the hydraulic valve body ground screw, cleaning contact surfaces if necessary; check for enlarged connector gaps; replace ABS or ABS/ASR computer if needed. State 4: ABS warning light illuminates during high-speed driving. Cause: During high-speed driving, the ABS computer detects significant difference between rear and front wheel speed signals; incorrect tire or wheel rim specifications. Solution: Refer to vehicle's specified tire and wheel rim sizes, typically listed on the fuel filler cap label. State 5: ABS warning light intermittently illuminates. Cause: Improper brake light switch adjustment; poor internal contact in brake lights. Solution: With engine running, press brake pedal fully while manually pushing brake switch linkage downward to complete self-setting position; replace brake light switch if necessary. When the ABS warning light is on, it's recommended not to continue driving as it indicates a fault in the anti-lock braking system. During emergency braking, locked wheels may cause loss of vehicle control and skidding, preventing the driver from decelerating or adjusting the vehicle's path, posing significant safety risks.