Hard Brake Pedal Diagnosis
A consistently hard brake pedal indicates a lack of power brake assist, often due to a failed vacuum booster, vacuum leak, or faulty check valve. This requires immediate attention as it significantly increases stopping distance.
Diagnosis Details
Possible Causes
Failed brake booster (vacuum leak or diaphragm rupture)
Faulty brake booster check valve (stuck closed or leaking)
Vacuum hose leak or disconnection between engine and booster
Brake booster vacuum pump failure (on diesel or some gasoline engines)
Related OBD-II Codes
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What You Should Do
Check brake booster vacuum supply: with engine off, pump brake pedal several times to deplete vacuum, then start engine while pressing pedal.
If pedal softens, booster is working.
If pedal remains hard, inspect vacuum hose and check valve for leaks or blockage.
Replace faulty components as needed.
Related Repairs
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Disclaimer: This AI-generated diagnosis is for informational reference only. Always consult a qualified mechanic for an in-person inspection. AutOwner is not responsible for decisions made based on this information.