C0038 DTC: Left Front Wheel Speed Sensor Circuit High
What Does C0038 Mean?
Diagnostic Trouble Code (DTC) C0038 indicates that the ABS module has detected a voltage or signal level above the expected operating range in the left front wheel speed sensor circuit. This is commonly caused by an open circuit, high circuit resistance, damaged wiring, poor electrical connections, or a faulty wheel speed sensor.
Symptoms
- ABS warning light ON
- Traction Control (TCS) warning light
- 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 left front wheel speed sensor
- Open circuit in the sensor wiring
- Loose or disconnected electrical connector
- Corroded connector terminals
- Damaged wiring harness
- Faulty tone ring (reluctor ring)
- Faulty ABS control module (rare)
Typical Diagnostic Flow
How to Diagnose C0038
- Read ABS fault codes using a professional scan tool.
- Monitor live wheel speed data while driving.
- Compare the left front wheel speed with the other three wheels.
- Inspect the sensor wiring for open circuits or damaged insulation.
- Check the connector for loose, bent, or corroded terminals.
- Inspect the tone ring for damage or excessive rust.
- Measure sensor resistance and circuit voltage according to manufacturer specifications.
Typical Values
- All wheel speed sensors should report similar wheel speeds.
- A consistently high circuit voltage usually indicates an open circuit or poor electrical connection.
- Exact 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
- C0035
- C0036
- C0037
- C0039
- C0040
Frequently Asked Questions
Can I drive with C0038?
Yes, but the ABS, Traction Control, and Stability Control systems may be disabled. Normal braking remains available, but vehicle stability and braking performance on slippery roads may be reduced.
What is the most common cause of C0038?
The most common causes are an open circuit, damaged wiring, a loose connector, corroded terminals, or a faulty left front wheel speed sensor.
Will clearing the DTC permanently fix C0038?
No. Clearing the code only removes it temporarily. If the high-voltage condition remains, the ABS module will detect the fault again during its next self-test.