Wheel Speed Sensor Signal - Circuit Intermittent
Intermittent signal issue from a wheel speed sensor.
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 system isn't getting a steady signal from one of the wheel speed sensors, making it hard for the ABS or traction control system to know how fast a wheel is spinning.
What the computer is actually seeing
The ABS module expects a consistent voltage signal between 0.5V and 12V from the wheel speed sensor as the wheel turns. If it sees a drop or erratic signal (under 0.5V or over 12V), it triggers the C1378 code.
What a healthy reading looks like
Wheel speed sensors typically output a frequency signal that corresponds with the wheel's rotation speed, usually in the range of 0 to 800Hz depending on vehicle speed.
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.
- 1Check the vehicle's wiring harness and connectors at the wheel speed sensor for any visible damage or corrosion.
- 2Test the resistance of the wheel speed sensor; it should be typically around 1kΩ to 2kΩ. If it’s out of spec, replace the sensor.
- 3Check the sensor output with a scan tool while driving; you should see the readings change smoothly. If it drops or spikes, replace the sensor.
- 4Inspect the ABS module for any additional fault codes that might indicate external issues affecting the sensor's signal.
Common causes
- Faulty wheel speed sensor
- Damaged wiring or connectors
- Corrosion at connectors
- Insufficient wheel bearing clearance
- Issues with the ABS control module
Typical repair cost
$$
Related codes
Frequently asked questions
Can I still drive with this code?
Yes, but it may affect the ABS or traction control functionality, potentially compromising safety.
Will this issue come back after clearing the code?
It can if the underlying issue isn't fixed; keep an eye on it.
Why does this code often pair with other codes?
Wheel speed issues can affect multiple systems, often showing related faults in ABS, traction control, or stability control.
Working a real vehicle right now?
Let DiagCoach walk you through it live with your specific symptoms, vehicle, and what you've already checked.
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