Excessive nitrogen oxides (NOx) emission
Perform troubleshooting referring to the followings when ECM has detected no DTC and no abnormality has been found in Visual Inspection:M13A without VVT and Engine Basic Inspection:M13A without VVT .
Condition Possible Cause Action
Excessive nitrogen oxides (NOx) emission
Fuel pressure out of specification
Lead contamination of three way catalytic converter
Check for absence of filler neck restrictor
Closed loop system (A/F feed back compensation) fails
– Faulty TP sensor
– Faulty ECT sensor or MAP sensor
– Faulty oxygen sensor
Faulty injector
Faulty ECM
Faulty EGR system (if equipped)