Damaged or disconnected rear drive shaft speed sensor wiring harness; Failed rear drive shaft speed sensor; Corroded or loose electrical connector at the sensor or control module; Open circuit in the signal or ground circuit; Short to voltage in the sensor circuit; Faulty control module (rare but possible)

DTC codes / C05xx · Brakes, steering and suspension / C05F1

C05F1Rear Drive Shaft Speed Sensor Circuit High

Q: What does code C05F1 mean?

Rear Drive Shaft Speed Sensor Circuit High. The C05F1 code indicates that the rear drive shaft speed sensor circuit is reporting a voltage higher than the manufacturer's expected range, which the control module interprets as a fault. The computer detects this by monitoring the sensor signal and seeing it stay above a calibrated threshold for a set period, often indicating an open circuit, short to voltage, or sensor failure.

The C05F1 code indicates that the rear drive shaft speed sensor circuit is reporting a voltage higher than the manufacturer's expected range, which the control module interprets as a fault. The computer detects this by monitoring the sensor signal and seeing it stay above a calibrated threshold for a set period, often indicating an open circuit, short to voltage, or sensor failure.

SystemChassis

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaBrakes, steering and suspension

Symptoms you may notice

Illumination of the anti-lock brake system (ABS) warning light or traction control light
Often no symptoms besides the warning light, especially if the fault is intermittent
Erratic or disabled traction control and stability control functions
Possible ABS deactivation, leading to conventional braking without anti-lock assistance
In some vehicles, a reduction in engine power or limp mode due to safety system integration
Speedometer inaccuracy or cruise control malfunction if the sensor signal is used for vehicle speed

Common causes, most likely first

Damaged or disconnected rear drive shaft speed sensor wiring harness
Failed rear drive shaft speed sensor
Corroded or loose electrical connector at the sensor or control module
Open circuit in the signal or ground circuit
Short to voltage in the sensor circuit
Faulty control module (rare but possible)

How to diagnose and fix it

Perform a visual inspection of the sensor and wiring for obvious damage, corrosion, or loose connections
Use a scan tool to read live data from the rear drive shaft speed sensor and compare with other wheel speed sensors
Check the sensor's resistance and output voltage with a multimeter according to manufacturer specifications
Inspect the wiring harness for continuity and shorts to voltage or ground, repairing as needed
Replace the rear drive shaft speed sensor if testing indicates it is faulty
Clear the diagnostic trouble codes and verify the repair by test-driving the vehicle and monitoring sensor data
If the code persists, diagnose the control module and its connections, consulting factory service information for pinpoint tests

Don't overlook the wiring harness

A common cause of this code is a chafed or broken wire in the harness near the rear drive shaft, often due to road debris or flexing, which can be missed if only the sensor is replaced.
The code does not always mean the sensor itself has failed; a poor ground connection at the chassis can cause a high voltage reading on the signal circuit.
In some vehicles, the rear drive shaft speed sensor is used for the speedometer and cruise control, so a fault can cause those systems to act up even if ABS seems fine.
After replacing the sensor, the code may not clear immediately if the control module requires a drive cycle to self-test; always follow the manufacturer's verification procedure.
Misdiagnosis often occurs when technicians replace the sensor without checking the connector terminals for corrosion or spread pins, which can mimic a sensor failure.

Can I keep driving with C05F1?

You can generally continue driving with this code, but be aware that ABS and traction control may be disabled, reducing safety in slippery conditions or emergency braking. Avoid aggressive driving and have the fault diagnosed soon to restore full safety system functionality.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.