What causes the ABS light to illuminate in a Skoda Fabia?

[EmmanuelRose]

ABS light illumination can occur in various states, with different causes and solutions for each state, as detailed below: State 1: ABS warning light stays on continuously (most common). Cause 1: The ABS wheel speed sensor's sensing area is covered by dirt, mud, or other contaminants, affecting the sensor's ability to detect the corresponding speed signal. This prevents the ABS control unit from determining the vehicle speed and calculating 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 tone ring to restore normal function. Cause 2: Poor signal transmission due to loose connections in the system wiring or poor contact in the ABS relay, leading to system failure. Solution: Inspect the wiring connections and reconnect any loose parts. State 2: ABS warning light illuminates intermittently and turns off when accelerating. Cause: When multiple electrical devices are in use, the battery voltage drops below 10.5V. As the engine speed increases and voltage rises, the ABS indicator turns off. This may also occur if the ABS system's power supply voltage is too low due to poor terminal contact or inadequate grounding. 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 stays on after engine start and only turns off when the engine is turned off (IGFF). Cause: Poor grounding connection in the ABS hydraulic valve body; poor contact in the ABS hydraulic valve body's wiring connector; ABS control unit failure. Solution: Loosen and then retighten the grounding screw on the hydraulic valve body, cleaning the contact surface if necessary; check if the connector gap has widened; replace the ABS or ABS/ASR control unit. State 4: ABS warning light illuminates during high-speed driving. Cause: During high-speed driving, the ABS control unit detects a significant discrepancy between the 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 illuminates intermittently. Cause: Improper adjustment of the brake light switch; poor internal contact in the brake light. Solution: With the engine running, depress the brake pedal and use a finger to push the brake switch linkage down fully, then release the brake pedal to complete the self-setting position; replace the brake light switch if necessary. If the ABS warning light is on, it is advisable not to continue driving, as it indicates a fault 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.

[OMatteo]

As a seasoned driver with decades of experience, when I see the ABS light on in a Skoda Fabia, I immediately think of several common causes—especially dirty or faulty wheel sensors, since rain and snow can easily clog the signals and trigger false alarms. The ABS module itself might also be damaged; that thing is tucked away inside the car and costly to repair. Once the light comes on, the braking system still works, but wheels may lock up during emergency stops, increasing accident risks. That’s why I always advise slowing down immediately and heading to a professional shop for diagnosis. In the Skoda lineup, the Fabia’s sensors sit lower and collect dust easily, so regular wheel cleaning helps prevent issues. During diagnostics, it’s best to read fault codes rather than tampering with wiring harnesses—modern electronics are sensitive, and mishandling can make repairs even harder. I remember back in my youth, fixing an older car’s ABS light was as simple as replacing a sensor. Nowadays, with cars being more electronic, problems are trickier, but safety should never be ignored—get it fixed when needed.