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 is having trouble reading the speed of the right back wheel. It's like when your game controller can't tell how fast you're moving in a racing game.
The C120B code is triggered when the ABS module detects a high voltage signal from the rear right wheel speed sensor circuit.
The wheel speed sensor is part of the Anti-lock Braking System (ABS) and monitors the rotational speed of each wheel. A 'Circuit High' code indicates that the sensor is sending a voltage signal that is higher than expected, which could be due to a short circuit or faulty sensor.
• ABS warning light on the dashboard
• Reduced braking performance
• Inconsistent speedometer readings
• Faulty rear right wheel speed sensor
• Damaged or corroded wiring or connectors
• Short circuit in the sensor circuit
ABS: Anti-lock Braking System
OBD-II: On-Board Diagnostics II
• Inspect the rear right wheel speed sensor for damage.
• Check the wiring and connectors for corrosion or damage.
• Use a multimeter to test the voltage output from the sensor.
• Replace the rear right wheel speed sensor if faulty.
• Repair or replace damaged wiring or connectors.
• Clear the code and test drive to ensure the issue is resolved.
• OBD-II scanner
• Multimeter
• Basic hand tools
$100 - $300
Moderate
• Toyota Camry
• Ford Focus
• Honda Accord
• Regularly inspect ABS components for wear and tear.
• Keep wheel sensors and connectors clean.
• Avoid driving through deep water or mud.
Sensor Issue
• Do not ignore the ABS warning light as it affects braking safety.
• Consult a professional mechanic if unsure about repairs.
Check with your vehicle manufacturer; ABS components may be covered under warranty.
The C120B code has been commonly reported in vehicles with over 100,000 miles, often due to sensor wear.
Moderate – While the vehicle is still drivable, braking performance may be compromised.
Driving with a faulty ABS sensor can increase the risk of accidents due to impaired braking ability.
• Vehicle parked on a level surface
• Ignition in the 'On' position without starting the engine
The rear right wheel speed sensor is located near the brake rotor on the passenger side of the vehicle.
Q: Can I drive with the C120B code?
A: While you can drive, it's not recommended as it may affect braking performance.
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.
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