Hard Brake Pedal Diagnosis - Honda Civic 2019
A consistently hard brake pedal indicates a loss of power brake assist, likely due to a failed vacuum booster, a vacuum leak, or a faulty check valve. This condition requires immediate attention as it significantly increases stopping distance and driver effort.
Diagnosis Details
Possible Causes
Failed brake booster (vacuum assist unit) - internal diaphragm leak or mechanical failure
Vacuum hose leak or disconnected hose between intake manifold and booster
Faulty brake booster check valve (one-way valve) allowing vacuum loss
Clogged or restricted vacuum source (intake manifold port or carbon buildup)
Related OBD-II Codes
Not satisfied with this diagnosis?
Try Another DiagnosisWhat To Do Next
What You Should Do
Inspect the brake booster vacuum hose for cracks, disconnection, or leaks.
Check the check valve operation (should hold vacuum one way).
Test booster function by pumping brake pedal with engine off, then start engine; pedal should drop slightly if booster is working.
If no drop, replace booster.
Also verify engine vacuum at idle (should be 18-22 inHg).
Share this diagnosis
Help others with similar symptoms
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.
