On-Board Diagnosis

ON-BOARD DIAGNOSIS LOGIC
With Mixture Ratio Self-Learning Control, the actual mixture ratio can be brought closely to the theoretical mixture ratio based on the mixture ratio feedback signal from the front heated oxygen sensor. The Engine Control Module (ECM) calculates the necessary compensation to correct the offset between the actual and the theoretical ratios.

In case the amount of the compensation value is extremely large, the ECM judges the condition as the fuel system malfunction and light up the Malfunction Indicator Lamp (MIL) (two trip detection logic).