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 reading the speed of the left back wheel. It's like when your bicycle speedometer isn't working right and you can't tell how fast you're going.
The vehicle's control module has detected an issue with the signal from the left rear wheel speed sensor, which is not within the expected range.
The C0660 code indicates that the signal from the left rear wheel speed sensor B is not performing within the expected parameters. This sensor is responsible for sending data about the wheel's speed to the vehicle's control module, which uses this information for functions like ABS and traction control.
• ABS warning light on
• Traction control warning light on
• Inconsistent speedometer readings
• Faulty wheel speed sensor
• Damaged wiring or connectors
• Malfunctioning ABS module
ABS: Anti-lock Braking System
OBD-II: On-Board Diagnostics II
• Perform a visual inspection of the wheel speed sensor and wiring.
• Use a multimeter to check the sensor's electrical resistance.
• Scan the vehicle with an OBD-II scanner to confirm the code.
• Replace the faulty wheel speed sensor.
• Repair or replace damaged wiring or connectors.
• Replace the ABS module if necessary.
• OBD-II scanner
• Multimeter
• Socket set
$150 - $400
Moderate
• Chevrolet Tahoe
• GMC Yukon
• Cadillac Escalade
• Regularly inspect the wheel speed sensors.
• Ensure wiring and connectors are intact.
• Avoid driving through deep water.
Sensor Issue
• Do not ignore the ABS warning light.
• Have the vehicle inspected by a professional if unsure.
• Avoid harsh driving conditions until repaired.
Check with your vehicle manufacturer for specific warranty coverage on ABS components.
This code has been associated with issues in vehicles with ABS systems dating back to the early 2000s.
Moderate – While the vehicle may still be drivable, ABS and traction control functions may be compromised.
Driving with a faulty wheel speed sensor can affect braking performance and vehicle stability. It is recommended to address this issue promptly.
• Vehicle stationary
• Ignition on, engine off
The left rear wheel speed sensor is located near the brake assembly of the left rear wheel.
Q: Can I drive my car with the C0660 code?
A: While you can drive the car, it's not recommended as the ABS and traction control systems may not function properly.
Q: How can I reset the ABS warning light?
A: The light can be reset by fixing the underlying issue and using 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.
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