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DTC codes / C00xx · Brakes, steering and suspension / C0064

C0064Right Rear Wheel Speed Sensor Signal Erratic

C0064 means the anti-lock brake system (ABS) module has detected an erratic signal from the right rear wheel speed sensor, meaning the signal is not consistent with vehicle speed or the other wheel sensors. The computer compares the right rear sensor's pulses to the other three and flags the code when the pattern is irregular, missing, or noisy.

SystemChassis
Code typeGeneric (all makes)
SeverityMedium
Fix difficultyIntermediate
AreaBrakes, steering and suspension

Symptoms you may notice

  • ABS warning light illuminated on the dashboard
  • Traction control or stability control warning light also on
  • ABS may deactivate, leaving conventional braking only
  • Speedometer may fluctuate or read incorrectly if the sensor feeds the speed display
  • Often no symptoms besides the warning light, with normal braking feel

Common causes, most likely first

  1. Damaged or corroded right rear wheel speed sensor wiring or connector
  2. Debris or metal shavings stuck to the sensor tip or tone ring
  3. Worn, cracked, or dirty tone ring (reluctor ring) on the right rear hub
  4. Failed right rear wheel speed sensor
  5. Excessive wheel bearing play or hub runout affecting sensor air gap
  6. Water intrusion or road salt corrosion in the sensor circuit
  7. Faulty ABS module or poor ground connection (less common)

How to diagnose and fix it

  1. Inspect the right rear sensor, connector, and wiring for damage, corrosion, or loose pins
  2. Clean the sensor tip and tone ring of metal debris and road grime
  3. Check the tone ring for cracks, missing teeth, or excessive rust and replace if damaged
  4. Measure the sensor air gap and check wheel bearing play at the right rear hub
  5. Test the sensor signal with a multimeter or oscilloscope while spinning the wheel
  6. If the sensor or ring is faulty, replace the affected component and clear the code
  7. Verify live wheel speed data on a scan tool matches the other wheels during a road test

What erratic really means on a wheel sensor

  • An erratic signal often comes from a loose or corroded connector rather than a failed sensor, so inspect the wiring before replacing parts.
  • Metal debris or a damaged tone ring can mimic a bad sensor, and cleaning or replacing the ring may fix the code without a new sensor.
  • A worn wheel bearing can change the air gap and cause an erratic signal, so check for play and noise at the right rear wheel.
  • The code can set intermittently from water intrusion after rain or a car wash, so a dry-weather code may not reappear immediately.
  • Do not assume the ABS module is faulty until the sensor circuit and tone ring have been thoroughly tested.

Can I keep driving with C0064?

The vehicle remains safe to drive with normal brakes, but ABS and traction control may be disabled, so avoid hard braking or slippery conditions until repaired. Have the fault diagnosed soon to restore full safety system function.

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.

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