Monitor Description

The intake air flow meter sub-assembly is a sensor that measures incoming air flow from the throttle valve. The ECM determines a length of time fuel is injected based on this information to provide an appropriate air/fuel ratio. The intake air flow meter sub-assembly is integrated with platinum filament, which is contact with induction air. When a specific amount of voltage is applied from the ECM, it is heated to a predetermined temperature. Also, induction air cools the platinum filaments and the integrated thermistor to cause a change in resistance. In order to maintain an electric current at a constant level, the electric current which is sent to the intake air flow meter sub-assembly is adjusted by the ECM. The voltage level is proportional to a flow rate measured by the sensor. The ECM uses this information is used to calculate an amount of induction.

An average engine load value ratio is monitored by the ECM to check the intake air flow meter sub-assembly for malfunction. An average engine load value ratio is a result of comparison between an average engine load as calculated from the intake air flow meter sub-assembly output and an average engine load as estimated based on operating conditions (such as engine speed and throttle opening angle). When the average engine load value ratio is less than a threshold value, the ECM judges that induction flow rate is low. On the other hand, when the average engine load value ratio exceeds the threshold value, the ECM judges that induction flow rate is high.

If this condition is detected consecutively in 2 drive cycles, the MIL illuminates and the DTC is stored.