Wheel Speed Sensor Circuit Malfunction
Indicates a problem with the wheel speed sensor circuit in the ABS system.
Heads up: this code wasn't in our hand-written library yet, so DiagCoach AI built this page on the fly. Double-check critical specs against service info before condemning parts.
What it means (plain English)
The ABS computer is not getting the right signal from the wheel speed sensor. This sensor usually produces a voltage signal that helps measure how fast the wheels are turning, typically around 0 to 5 volts depending on speed.
What the computer is actually seeing
The ABS control module expects a smooth voltage signal that varies with wheel speed typically between 0.5V (stationary) and up to 5V (at high speed). If it sees no signal or an open circuit, it'll throw the C0140 code.
What a healthy reading looks like
Wheel speed signal voltage should be between 0.5V to 5V while the vehicle is moving; rest voltage should be around 0V.
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 wheel speed sensor wiring and connector for damage or corrosion. Fix or replace as necessary. Decision point: If wiring is okay, proceed to step 2. If damaged, repair it and retest.
Common causes
- Damaged wheel speed sensor
- Corroded or damaged wiring
- Faulty ABS module
- Poor connection at the sensor harness
- Signal interference from other electrical components
Typical repair cost
$$-$$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It depends on the vehicle. If the ABS lights are on, the vehicle might still be drivable, but ABS functionality will be compromised, which could affect stopping in slippery conditions.
Will this code come back after clearing?
If the underlying issue is not resolved, the code will likely come back.
Does this code pair with any other codes?
Yes, it's often seen with other codes related to ABS issues such as C0141 or C0142.
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