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's computer is getting a weak signal from the sensor that measures how fast the right rear wheel is spinning.
The C0668 code is triggered when the vehicle's control module detects a low voltage signal from the right rear wheel speed sensor B circuit.
The right rear wheel speed sensor is part of the vehicle's anti-lock braking system (ABS). It sends data about the wheel's speed to the ABS control module. A 'Circuit Low' code indicates that the voltage signal from the sensor is below the expected range, which can affect the ABS functionality.
• ABS warning light on
• Traction control warning light on
• Inoperative ABS system
• Faulty right rear wheel speed sensor
• Damaged or corroded wiring or connectors
• Faulty ABS control module
ABS: Anti-lock Braking System
OBD-II: On-Board Diagnostics, Second Generation
• Inspect the right rear wheel speed sensor and wiring for damage.
• Check the electrical connections for corrosion or looseness.
• Test the sensor's output with a multimeter.
• Replace the faulty wheel speed sensor.
• Repair or replace damaged wiring or connectors.
• Replace the ABS control module if necessary.
• OBD-II scanner
• Multimeter
• Socket set
$150 - $400
Moderate
• Chevrolet Silverado
• GMC Sierra
• Cadillac Escalade
• Regularly inspect ABS components.
• Keep wheel sensors clean and free of debris.
• Ensure proper maintenance of the braking system.
Sensor Issue
• Do not ignore the ABS warning light.
• Have the vehicle inspected by a professional if the light comes on.
Check your vehicle's warranty for coverage on ABS components.
This code commonly appears in vehicles with high mileage or those exposed to harsh environmental conditions.
Moderate – While the vehicle is still drivable, the ABS system may not function properly, affecting braking performance.
Driving with a malfunctioning ABS system can increase stopping distances and the risk of skidding.
• Vehicle parked on a flat surface
• Ignition in the 'On' position
The right rear wheel speed sensor is located near the wheel hub on the right rear wheel.
Q: Can I drive with the C0668 code?
A: Yes, but it's not recommended as the ABS system may not work properly.
Q: How do I reset the ABS warning light?
A: Fix the issue causing the code, then 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.
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