Excessive hydrocarbon (HC) emission or carbon monoxide (CO)
Perform troubleshooting referring to the followings when ECM has detected no DTC and no abnormality has been found in Visual Inspection:M13A with VVT and Engine Basic Inspection:M13A with VVT .
Condition Possible Cause Action
Excessive hydrocarbon (HC) emission or carbon monoxide (CO)
Faulty spark plug
Leaky or disconnected high-tension cord
Faulty ignition coil with ignitor
Low compression
Lead contamination of three way catalytic converter
Check for absence of filler neck restrictor
Faulty evaporative emission control system
Fuel pressure out of specification
Closed loop system (A/F feed back compensation) fails
– Faulty TP sensor
– Poor performance of ECT sensor or MAF sensor
Faulty injector(s)
Faulty ECM
Engine not at normal operating temperature
Clogged air cleaner
Vacuum leaks
Camshaft position control (VVT) system out of order