C0063 DTC: Left Rear Wheel Speed Sensor Circuit Low Frequency

What Does C0063 Mean?

Diagnostic Trouble Code (DTC) C0063 indicates that the ABS control module has detected a wheel speed signal from the left rear wheel speed sensor that is lower in frequency than expected. This usually means the sensor is producing fewer signal pulses than required, resulting in inaccurate wheel speed information. As a result, the Anti-lock Braking System (ABS), Traction Control System (TCS), and Electronic Stability Control (ESC) may not operate correctly.

Symptoms

• ABS warning light illuminated.
• Traction Control warning light ON.
• Electronic Stability Control warning.
• Reduced ABS performance.
• Unexpected ABS activation.
• Traction Control disabled.
• Cruise control may be disabled on some vehicles.
• Additional ABS DTCs stored.

Common Causes

• Faulty left rear wheel speed sensor.
• Damaged or cracked tone ring.
• Excessive sensor-to-tone ring air gap.
• Wheel bearing wear causing incorrect sensor alignment.
• Metal debris attached to the magnetic sensor.
• Damaged sensor wiring.
• Loose or corroded electrical connector.
• Faulty ABS control module (rare).

Typical Diagnostic Flow

ABS Control Module

▼

Left Rear Wheel Speed Sensor

Wheel Rotation ○ ↻↻↻ Signal Frequency |||||||||||| ↓↓ |||||| Low Frequency

Low Frequency Signal Detected

▼

Inspect Sensor, Tone Ring, Wiring & Wheel Bearing

How to Diagnose C0063

• Read ABS fault codes using a professional scan tool.
• Monitor live wheel speed data during a road test.
• Compare the left rear wheel speed with the remaining wheels.
• Inspect the tone ring for missing or damaged teeth.
• Check the sensor air gap.
• Inspect the wheel bearing for excessive play.
• Inspect the wiring harness and connector.
• Clean metal particles from the magnetic sensor.

Typical Values

• Wheel speed signals should closely match the other wheels.
• Signal frequency should increase smoothly as vehicle speed increases.
• Specifications vary by vehicle manufacturer.

Estimated Repair Cost

• Wheel speed sensor replacement: $70–250
• Tone ring replacement: $80–300
• Wheel bearing replacement: $150–500
• Wiring repair: $50–200
• Connector replacement: $30–120
• ABS module replacement: $400–1,200

Related DTCs

• C0059
• C0060
• C0061
• C0062
• C0064

Frequently Asked Questions

Can I drive with C0063?

Yes. Normal braking remains available, but ABS, Traction Control, and Stability Control functions may be disabled until the problem is repaired.

What is the most common cause of C0063?

The most common causes are a faulty wheel speed sensor, damaged tone ring, excessive wheel bearing play, incorrect sensor air gap, or damaged wiring.

Will clearing the DTC permanently fix C0063?

No. Clearing the code only removes it temporarily. If the underlying fault remains, the ABS control module will detect the problem again during the next drive cycle.