Hard Brake Pedal Diagnosis
A consistently hard brake pedal in a 2020 Toyota RAV4 indicates a loss of power brake assist, typically due to a failed vacuum booster, a vacuum leak, or a faulty brake booster check valve. This condition significantly increases stopping distance and pedal effort.
Diagnosis Details
Possible Causes
Failed brake booster (vacuum assist unit) – internal diaphragm leak or mechanical failure
Vacuum leak at booster hose, check valve, or intake manifold connection
Faulty brake booster check valve (allows vacuum loss)
Clogged or restricted vacuum line to booster
Brake pedal linkage or master cylinder binding (less common with hard pedal)
Related OBD-II Codes
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What You Should Do
Inspect the brake booster vacuum hose and check valve for cracks or leaks.
Test booster function by pumping brake pedal with engine off (should get hard), then start engine – pedal should drop slightly if booster works.
If no drop, suspect booster failure.
Check for vacuum at booster hose with engine running.
Replace booster or check valve as needed.
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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.
