ABS Wheel Speed Sensor A Signal Fault
The ABS system detected a fault with the wheel speed sensor A.
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What it means (plain English)
The ABS control module isn’t getting the expected signal from the wheel speed sensor A, which helps it control braking. This sensor measures how fast each wheel is turning, and if it’s broken or sending the wrong data, the ABS can’t work properly.
What the computer is actually seeing
The ABS module looks for a consistent voltage signal between 0.5V to 2.5V that varies with wheel speed. If the signal drops below 0.5V or stays fixed when the vehicle is in motion, a fault is triggered.
What a healthy reading looks like
The wheel speed sensor A should provide a variable voltage between 0.5V to 2.5V at different wheel speeds, ideally changing as the vehicle accelerates or decelerates.
Guided diagnostic — the DiagCoach way
Don't just throw parts at it. Walk through these in order — each step tells you whether to keep going or stop and fix what you found.
- 11. Inspect the wiring and connector for the wheel speed sensor A for wear, damage, or corrosion. If damaged, repair or replace.
- 22. Check the sensor resistance. Should be between 1,000 to 2,500 ohms. If out of spec, replace sensor.
- 33. With the vehicle on a lift, manually spin the wheel. Use a multimeter at the sensor connector; expect a voltage reading that increases as you spin faster. If no change, replace the sensor.
- 44. If the sensor checks out, test the ABS module for faults. If it shows other error codes, investigate further. If clear, consider assessing the ABS system and wheel hardware.
Common causes
- Damaged wheel speed sensor A
- Faulty wiring or connectors
- Corrosion in the electrical connectors
- ABS module malfunction
- Physical issues with the wheel (e.g., bearings)
Typical repair cost
$$ - $$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
Yes, but your ABS system may not function effectively, increasing stopping distance.
Will this code come back after clearing?
If the underlying issue isn’t resolved, it will likely return when the vehicle is driven.
Why does this code point to the front sensor, but I have rear issues?
The system processes information from multiple sensors, and the front sensor A often impacts overall ABS performance.
Working a real vehicle right now?
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