Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
This means there's a problem with the part of the car that helps you brake easily. It's like when your bicycle brakes don't work well because the cable is loose.
The P120F code indicates that the brake booster pump control circuit is experiencing a low voltage condition.
The brake booster pump is an electronic component that helps provide additional force to the braking system. The control circuit for the pump is monitored by the vehicle's computer, and if the voltage is lower than expected, it triggers the P120F code.
• Reduced braking performance
• Brake warning light on the dashboard
• Unusual noises when braking
• Faulty brake booster pump
• Damaged wiring or connectors in the control circuit
• Failed brake booster pump relay
Brake Booster: A device that uses vacuum or hydraulic pressure to assist the driver in applying the brakes.
Relay: An electrical component that opens or closes a circuit electronically or electromechanically.
• Check for any blown fuses related to the brake booster pump.
• Inspect the wiring and connectors for damage or corrosion.
• Test the brake booster pump relay for proper operation.
• Replace the faulty brake booster pump.
• Repair or replace damaged wiring or connectors.
• Replace the brake booster pump relay if defective.
• Multimeter
• OBD-II scanner
• Basic hand tools (screwdrivers, pliers)
$150 - $500
Moderate
• Ford F-150
• Chevrolet Silverado
• Toyota Camry
• Regularly inspect brake system components.
• Ensure all electrical connections are secure and clean.
• Follow the manufacturer's maintenance schedule.
Brake System Issue
• Avoid driving at high speeds until the issue is resolved.
• Have the vehicle inspected by a professional mechanic as soon as possible.
Check with your vehicle manufacturer for warranty coverage on brake system components.
This code is typically associated with vehicles that have electronic brake booster systems, which have become more common in modern vehicles.
High – Brake system issues can affect vehicle safety and should be addressed immediately.
Driving with a malfunctioning brake system can be dangerous and may violate traffic safety laws.
• Vehicle must be running.
• Brake pedal must be applied to test the booster pump.
The brake booster pump is usually located near the brake master cylinder in the engine bay.
Q: Can I drive with a P120F code?
A: It's not recommended to drive with a P120F code as it indicates a potential issue with your braking system, which can be dangerous.
Q: How do I reset the P120F code?
A: After repairs, use an OBD-II scanner to clear the code. However, ensure the issue is fixed to prevent the code from returning.
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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