Engine Cranks But Won't Start When Warm
The engine cranks normally but fails to start when warm, indicating a fuel or ignition issue that is temperature-sensitive. Common causes include a failing fuel pump, faulty crankshaft position sensor, or vapor lock.
Diagnosis Details
Possible Causes
Faulty crankshaft position sensor (CKP) – fails when hot, losing signal to PCM
Fuel pump or fuel pump driver module failure – loses pressure when warm
Vapor lock in fuel lines (especially on hot days) – fuel vaporizes, preventing flow
Related OBD-II Codes
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What You Should Do
Check for spark and fuel pressure when warm.
Test crankshaft position sensor resistance and signal.
Inspect fuel pump relay and module.
Allow engine to cool and attempt restart to confirm temperature sensitivity.
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.
