Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
This code means that the car thinks the wrong part was used for the sensor that tells how fast the back right wheel is spinning.
The vehicle's computer has detected that the right rear wheel speed sensor does not match the expected specifications, possibly due to an incorrect part being installed.
The C066C code is triggered when the Electronic Brake Control Module (EBCM) identifies that the installed right rear wheel speed sensor does not match the expected characteristics or specifications. This could be due to an incorrect sensor being installed or a sensor that is not calibrated correctly for the vehicle.
• ABS warning light on
• Traction control light on
• Inconsistent speedometer readings
• Incorrect wheel speed sensor installed
• Faulty wheel speed sensor
• Incorrect calibration of the sensor
OBD-II: On-Board Diagnostics, a standardized system for self-diagnostics and reporting.
ABS: Anti-lock Braking System, a safety system that prevents the wheels from locking up during braking.
• Verify the part number of the installed sensor.
• Check the sensor's connection and wiring for damage.
• Compare the sensor's output with the expected values.
• Replace the incorrect sensor with the correct one.
• Repair or replace damaged wiring or connectors.
• Calibrate the sensor if necessary.
• OBD-II scanner
• Multimeter
• Wheel speed sensor removal tool
$100 - $300
Moderate
• Chevrolet Silverado
• GMC Sierra
• Cadillac Escalade
• Ensure correct part numbers when replacing sensors.
• Regularly check sensor connections.
• Use OEM parts for replacements.
Sensor Issue
• Consult a professional mechanic if unsure.
• Avoid driving in conditions where ABS is crucial until fixed.
Check vehicle warranty for coverage on sensor replacements.
This code has been more common in vehicles where aftermarket parts were used.
Moderate – While the vehicle can still be driven, the ABS and traction control systems may not function properly.
Driving with a malfunctioning ABS system can increase the risk of accidents in slippery conditions.
• Vehicle on a lift for wheel inspection
• OBD-II scanner connected to the vehicle
The right rear wheel speed sensor is located near the brake assembly of the right rear wheel.
Q: Can I drive with this code?
A: Yes, but be cautious as ABS and traction control may not work properly.
Q: How do I know if the sensor is incorrect?
A: Check the part number against the manufacturer's specifications.
Pro · Four-system diagnostics
A handheld scanner aimed at engine, transmission, ABS, and airbag diagnostic work.
Chassis and ABS faults usually need a scanner that can read brake-system data directly.
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Universal · Torque wrench
Useful when reassembly torque matters for wheel, suspension, and under-hood fasteners.
Useful when wheel, hub, or suspension hardware needs correct reassembly torque.
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Universal · Drive-on ramps
Helpful for safer access underneath the vehicle during exhaust, EVAP, and underbody inspection work.
Helpful for safer access during underbody inspection work.
View on AmazonThese are optional diagnostic tools, not guaranteed fixes. As an Amazon Associate I earn from qualifying purchases.