Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
This code means there's a problem with the part of the car that checks how hard you are pressing the brake pedal.
The brake pressure sensor monitors the pressure applied to the brake system. If there's an issue with the supply circuit, it may not function correctly.
The C05C9 code is triggered when the brake pressure sensor supply circuit is malfunctioning. This could be due to an electrical fault, such as an open or short circuit, or a failure in the sensor itself. The sensor is crucial for the ABS and stability control systems, which rely on accurate brake pressure readings.
• ABS warning light illuminated
• Brake system warning light on
• Reduced braking performance
• ABS system not functioning properly
• Stability control system disabled
• Faulty brake pressure sensor
• Open or shorted circuit in the sensor wiring
• Poor electrical connection at the sensor
• Blown fuse in the sensor circuit
• Faulty ABS control module
ABS: Anti-lock Braking System
Sensor: A device that detects or measures a physical property and records, indicates, or otherwise responds to it.
• Scan the vehicle for additional codes and freeze frame data.
• Inspect the brake pressure sensor wiring and connectors for damage.
• Check the fuse related to the brake pressure sensor circuit.
• Test the brake pressure sensor for proper operation.
• Inspect and test the ABS control module.
• Replace the faulty brake pressure sensor.
• Repair or replace damaged wiring and connectors.
• Replace blown fuses in the sensor circuit.
• Reprogram or replace the ABS control module if necessary.
• OBD-II scanner
• Multimeter
• Wiring repair tools
• Brake pressure sensor tester
$150 - $500
Moderate
• Chevrolet Silverado
• GMC Sierra
• Cadillac Escalade
• Regularly inspect brake system components.
• Ensure electrical connections are secure and free of corrosion.
• Perform routine maintenance checks on the ABS system.
Sensor Issue
• Do not ignore the ABS warning light.
• Have the brake system inspected by a professional.
• Avoid driving in conditions that require heavy braking until repaired.
Check with the vehicle manufacturer for warranty coverage on brake system components.
This code has been commonly reported in vehicles with electronic brake control systems, especially in models with advanced ABS and stability control features.
High – This issue affects the braking system, which is critical for vehicle safety.
Driving with a malfunctioning brake system can lead to accidents. Address this issue promptly to ensure vehicle safety.
• Vehicle parked on a level surface.
• Ignition in the 'on' position without starting the engine.
The brake pressure sensor is typically located near the master cylinder or integrated into the ABS module.
Q: What happens if I ignore this code?
A: Ignoring this code can lead to reduced braking performance and increased risk of accidents.
Q: Can I drive with this code?
A: It's not recommended to drive with this code active, as it affects the braking system's reliability.
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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