Monitoring Procedure

During ignition ON periods, the sensor output voltage is continuously monitored for high and low value. If a sustained high or low ECM input (indicating a harness or connector fault) is detected, the relevant DTC is stored.

The sensor output voltage is monitored during steady state engine operation. A judgement is made by the ECM for correct values from input information of engine speed and throttle angle. If the air flow differs from the expected value by a fixed amount then the range/performance failure judgement is made. The DTC is stored if the failure judgement is made on two successive trips.