LEMON Manuals
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Infiniti
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2020
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QX50 Essential, FWD
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Repair and Diagnosis
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Engine Performance
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System
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Engine Control System (DTC/Circuit Diagnosis) (5 Of 12)
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DTC/Circuit Diagnosis
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DTC P0420: Three Way Catalyst Function
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DTC Description
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Possible Cause
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Possible Cause
Three way catalyst (manifold)
Exhaust tube
Intake air leaks
Exhaust air leaks
Direct fuel injector
Port fuel injector
Direct fuel injector leaks
Port fuel injector leaks
Spark plug
Improper ignition timing