What Causes the ABS Light to Illuminate in a Volkswagen Golf?

[McIris]

ABS light illumination can occur in various states, with different causes and solutions for each state, as detailed below: State 1: ABS warning light remains constantly illuminated (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 or the 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 signal ring to restore normal function. Cause 2: Poor signal transmission due to loose system wiring connections or faulty ABS relay contacts, leading to system malfunction. Solution: Inspect wiring connections and reconnect any loose parts. State 2: ABS warning light intermittently illuminates but turns off during acceleration. Cause: When multiple vehicle electrical devices are in use, the battery voltage drops below 10.5V. As the engine speed increases and voltage rises, the ABS light turns off. This may also occur if the ABS system's power supply voltage is too low due to poor terminal contact or grounding issues. Solution: Check the battery's specific gravity; inspect the charging system; examine the power supply (e.g., voltage relay or poor power contact). State 3: ABS warning light remains illuminated after engine start and only turns off when the engine is turned off (IGFF). Cause: Poor grounding contact of the ABS hydraulic valve body; poor electrical connector contact of the ABS hydraulic valve body; ABS control module failure. Solution: Loosen and retighten the hydraulic valve body's grounding screw, cleaning the contact surface if necessary; check for enlarged connector gaps; replace the ABS or ABS/ASR control module. State 4: ABS warning light illuminates during high-speed driving. Cause: During high-speed driving, the ABS control module detects a significant discrepancy between rear and front wheel speed signals; 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; poor internal contact of 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 brake pedal to complete self-positioning; replace the brake light switch if necessary. If the ABS warning light is illuminated, it is advisable not to continue driving. An illuminated ABS light indicates a malfunction in the vehicle's anti-lock braking system. During emergency braking, if the wheels lock up, the vehicle may skid uncontrollably, preventing the driver from slowing down or adjusting the vehicle's trajectory, posing significant safety risks.

[DylanLynn]

That day when I was driving to buy groceries, the ABS light on my Volkswagen Golf suddenly lit up, flashing like a little warning sign, which instantly made me a bit nervous. A problem with the anti-lock braking system could affect safety, as the wheels might lock up and skid during emergency braking. I quickly pulled over, turned on the hazard lights, and popped the hood for a quick check. I found that the sensor on the left front wheel was completely covered in mud—common after driving on rough roads in the rain. Additionally, the brake fluid reservoir was below the minimum mark, likely due to a leaking seal from aging. My friend Lao Zhang mentioned that his car's ABS light was constantly on before, and it turned out the wheel speed sensor wiring harness had been chewed through by rats. Don’t underestimate this yellow warning light—it can be a lifesaver on slippery roads. If you notice an issue, it’s best to visit a repair shop the same day to read the fault codes. Don’t procrastinate like I did last time, waiting three to five days and nearly causing a rear-end collision on the highway.