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 sensor that helps your car know how much you're pressing the brake pedal.
The brake booster travel sensor measures how far the brake pedal is being pushed. If there's an electrical issue with this sensor, the car's computer can't accurately determine brake pedal position.
C1021 indicates an electrical fault in the brake booster travel sensor circuit. This sensor provides feedback to the vehicle's electronic control unit (ECU) about the position of the brake pedal. A malfunction could mean a short, open circuit, or poor connection.
• ABS warning light on
• Brake system warning light on
• Reduced braking performance
• Faulty brake booster travel sensor
• Damaged wiring or connectors
• ECU malfunction
Brake Booster: A component that amplifies the force applied to the brake pedal.
ECU: Electronic Control Unit, the computer that controls various vehicle functions.
• Check for any additional codes and clear them.
• Inspect the brake booster travel sensor and its wiring for damage.
• Test the sensor using a multimeter to ensure proper operation.
• Replace the brake booster travel sensor if faulty.
• Repair or replace damaged wiring or connectors.
• Reprogram or replace the ECU if necessary.
• OBD-II scanner
• Multimeter
• Screwdriver set
$100 - $300
Moderate
• Toyota Camry
• Honda Accord
• Ford Focus
• Regularly inspect brake system components.
• Ensure all electrical connections are secure.
• Schedule routine maintenance checks.
Sensor Issue
• Do not ignore the warning lights on your dashboard.
• Have your brake system inspected by a professional if you notice any issues.
Check with your vehicle manufacturer for warranty coverage on brake system components.
This code has been reported in vehicles with electronic brake systems, particularly those with advanced driver assistance features.
High – Brake system issues can compromise vehicle safety.
Driving with a faulty brake system can be dangerous and may violate vehicle safety regulations.
• Vehicle parked on a level surface
• Ignition in the 'On' position
The brake booster travel sensor is typically located near the brake pedal assembly or integrated within the brake booster.
Q: Can I drive with a C1021 code?
A: It's not recommended, as brake system issues can affect your ability to stop safely.
Q: How do I reset the C1021 code?
A: After repairs, use an OBD-II scanner to clear the code, but ensure the issue is fixed first.
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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