C0042 DTC: Right Front Wheel Speed Sensor Circuit Low
What Does C0042 Mean?
Diagnostic Trouble Code (DTC) C0042 indicates that the ABS control module has detected a voltage or signal level below the expected operating range in the right front wheel speed sensor circuit. This usually indicates a short to ground, excessive circuit resistance, damaged wiring, or a faulty wheel speed sensor.
Symptoms
- ABS warning light illuminated
- Traction Control (TCS) warning light ON
- Electronic Stability Control (ESC) warning
- ABS disabled during emergency braking
- Traction Control unavailable
- Cruise control may be disabled on some vehicles
- Additional ABS-related DTCs may be stored
Common Causes
- Faulty right front wheel speed sensor
- Sensor circuit shorted to ground
- Damaged wiring harness
- Loose, corroded, or water-damaged connector
- Damaged tone ring (reluctor ring)
- Wheel bearing wear causing an incorrect sensor air gap
- Faulty ABS control module (rare)
Typical Diagnostic Flow
How to Diagnose C0042
- Read ABS DTCs using a professional scan tool.
- Monitor live wheel speed data while driving.
- Compare the right front wheel speed with the other three wheels.
- Inspect the wiring harness for damage or contact with ground.
- Check the electrical connector for corrosion or moisture.
- Inspect the tone ring for cracks, rust, or missing teeth.
- Measure sensor resistance and supply voltage according to manufacturer specifications.
Typical Values
- All wheel speed sensors should display nearly identical vehicle speeds while driving.
- A low or missing signal usually indicates a sensor or circuit fault.
- Specifications vary by vehicle manufacturer.
Estimated Repair Cost
- Wheel speed sensor replacement: $70–250
- Wiring repair: $50–200
- Connector replacement: $30–120
- Tone ring replacement: $80–300
- Wheel bearing replacement: $150–500
- ABS module replacement: $400–1,200
Related DTCs
- C0040
- C0041
- C0043
- C0045
- C0050
Frequently Asked Questions
Can I drive with C0042?
Yes, but the ABS, Traction Control, and Stability Control systems may be disabled. Normal braking remains available, but braking performance on slippery roads may be reduced.
What is the most common cause of C0042?
The most common causes are a faulty right front wheel speed sensor, wiring shorted to ground, damaged connectors, or a defective tone ring.
Will clearing the DTC permanently fix C0042?
No. Clearing the code only removes it temporarily. If the low-voltage condition still exists, the ABS module will detect the fault again during its next self-test.