Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
The car's computer is having trouble getting a steady reading from the sensor that checks how fast the right rear wheel is spinning.
The vehicle's onboard computer has detected an inconsistent or erratic signal from the right rear wheel speed sensor.
The C066A code indicates a problem with the right rear wheel speed sensor's signal, which is used by the vehicle's ABS and traction control systems to monitor wheel speed. An intermittent or erratic signal can affect these systems' performance.
• ABS warning light on
• Traction control light on
• Inconsistent braking performance
• Faulty wheel speed sensor
• Damaged or corroded wiring/connectors
• Faulty ABS module
ABS: Anti-lock Braking System
OBD-II: On-Board Diagnostics, second generation
• Inspect the right rear wheel speed sensor for damage.
• Check the wiring and connectors for corrosion or damage.
• Test the sensor output with a multimeter.
• Replace the faulty wheel speed sensor.
• Repair or replace damaged wiring/connectors.
• Replace the ABS module if necessary.
• Multimeter
• OBD-II scanner
• Socket set
$100 - $300
Moderate
• Chevrolet Silverado
• GMC Sierra
• Cadillac Escalade
• Regularly inspect wheel speed sensors.
• Keep connectors clean and free of corrosion.
• Avoid harsh driving conditions that may damage sensors.
Sensor Issue
• Do not ignore the ABS warning light.
• Have the vehicle inspected by a professional if unsure.
• Avoid aggressive driving until the issue is resolved.
Check with the vehicle manufacturer for specific warranty coverage on ABS components.
Wheel speed sensor issues are common in vehicles with advanced ABS and traction control systems.
Moderate – While the vehicle is still drivable, the ABS and traction control systems may not function properly.
Driving with a malfunctioning ABS system may increase the risk of losing control during braking.
• Vehicle on a lift or jack stands
• Ignition on, engine off
The right rear wheel speed sensor is located near the wheel hub of the rear right wheel.
Q: Can I drive with a C066A code?
A: Yes, but be cautious as the ABS and traction control systems may not work properly.
Q: How can I reset the ABS light?
A: Fix the underlying issue and use an OBD-II scanner to clear the code.
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.