What is the reason for the ABS yellow light on the dashboard?
2 Answers
ABS light can indicate various conditions, each with different causes and solutions as follows: Condition 1: ABS warning light stays on constantly (most common). Cause 1: The ABS wheel speed sensor's sensing area is covered by mud, sludge, or other contaminants, affecting its ability to detect wheel speed signals. This prevents the ABS computer from determining vehicle speed or wheel slip rate, thus failing to issue appropriate braking commands. Solution: Clean the contaminants 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. Solution: Inspect all wiring connections and reconnect any loose parts. Condition 2: ABS warning light intermittently illuminates, but turns off during acceleration. Cause: When multiple electrical components are in use, battery voltage drops below 10.5V. The light extinguishes when engine speed increases and voltage rises. Possible low voltage supply to ABS system due to poor connections or grounding issues. Solution: Check battery specific gravity; inspect charging system; examine power supply (voltage relays or poor power connections). Condition 3: ABS warning light remains on after engine start until engine is turned off. Cause: Poor grounding connection of ABS hydraulic valve body; faulty wiring connections in hydraulic valve body; ABS computer malfunction. Solution: Loosen and retighten hydraulic valve body ground screw, clean contact surfaces if necessary; check for enlarged connector gaps; replace ABS or ABS/ASR computer if needed. Condition 4: ABS warning light illuminates during high-speed driving. Cause: ABS computer detects significant speed difference between front and rear wheels; incorrect tire or wheel rim specifications. Solution: Verify correct tire and wheel rim specifications as indicated on fuel filler door sticker. Condition 5: ABS warning light flashes intermittently. Cause: Improper brake light switch adjustment; internal contact issues in brake lights. Solution: With engine running, depress brake pedal and manually push switch linkage downward, then release pedal to reset position; replace brake light switch if necessary. When ABS warning light is on, continued driving is not recommended as it indicates anti-lock braking system malfunction. During emergency braking, locked wheels may cause loss of vehicle control and skidding, preventing proper deceleration or trajectory adjustment, creating significant safety hazards.
Just a couple of days ago, I ran into this issue. While driving, I suddenly noticed the ABS yellow light came on, so I immediately drove to the repair shop for a check. They found that the wheel speed sensor on the left front wheel was covered in mud. The mechanic said this is the most common issue—dirty or damaged sensors can trigger false alarms. Other possibilities include loose wiring, damage from rodents chewing through the cables, or problems with the ABS control module itself. All these can interfere with proper readings. The most troublesome issue is ABS pump failure, but that's very rare. I remember the mechanic also mentioned trying to avoid puddles on the road, as they can easily splash mud and debris onto the sensors. Generally, in such cases, don’t rush to replace parts—reading the fault codes to pinpoint the issue is more reliable.
