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.
Diagnosis Details
Possible Causes
Faulty crankshaft position sensor (CKP) – fails when hot, causing loss of spark/fuel injector pulse.
Fuel pump or fuel pressure regulator issue – vapor lock or failing pump loses prime when hot.
Engine coolant temperature sensor (ECT) sending incorrect signal to PCM, flooding or leaning mixture.
Related OBD-II Codes
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What You Should Do
Check for spark and fuel pressure when the engine is warm and failing to start.
Test crankshaft position sensor resistance and signal.
Scan for diagnostic trouble codes.
If no spark, replace CKP sensor.
If fuel pressure is low, test fuel pump and relay.
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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.
