Wheel Speed Sensor Input Signal A
There’s a problem with the wheel speed sensor A signal.
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What it means (plain English)
The computer is not getting a proper signal from the wheel speed sensor A, which helps control anti-lock brakes and stability systems.
What the computer is actually seeing
The wheel speed sensor A should provide a voltage signal that varies as the wheel turns. If there are too many drop-outs or if the signal is out of the expected range, the computer flags this code.
What a healthy reading looks like
The wheel speed sensor typically outputs a voltage signal of 0.5 to 3 volts, fluctuating with wheel speed; it should not drop below 0.1 volts or exceed 4.0 volts under normal operation.
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 at the wheel speed sensor A for signs of damage or corrosion. Replace or repair if necessary. Decision: If wiring is damaged, fix it and retest; if not damaged, proceed to next step.
- 22. Measure the voltage output of the wheel speed sensor A while the vehicle is in motion. It should fluctuate between 0.5 to 3 volts. Decision: If voltage is within range, the sensor is likely good; go to step 3. If voltage is out of range, replace the sensor.
- 33. Check the sensor's connector and harness for continuity to the ABS module. Use a multimeter to ensure there are no breaks in the circuit. Decision: If there is continuity, suspect the ABS module; if no continuity, repair the circuit.
Common causes
- Damaged wheel speed sensor
- Corroded or broken wiring harness
- Faulty ABS module
- Wheel bearing issues
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
Moderate severity indicates you can still drive, but it may affect braking performance in slippery conditions.
Will this code come back after clearing it?
If the issue remains unresolved, it will likely come back after clearing the code.
Why does this code sometimes appear with C1540 or C1541?
These codes indicate issues with other wheel speed sensors or related systems, often pointing to a broader failure in the ABS system.
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