Circuit/System Description

The mass air flow (MAF) sensor is integrated with the intake air temperature (IAT) sensor. The MAF sensor is an air flow meter that measures the amount of air entering the engine. The engine control module (ECM) uses the MAF sensor signal to provide the correct fuel delivery for all engine speeds and loads. A small quantity of air entering the engine indicates a low load or idle condition. A large quantity of air entering the engine indicates a high load condition.

The ECM applies 5 volts to the MAF sensor on the MAF sensor signal circuit. The sensor uses the voltage to produce a frequency based on the inlet air flow through the sensor bore.

The MAF sensor is supplied power through the powertrain relay and a fuse. The ECM enables the MAF sensor only during engine run mode by grounding the MAF control circuit via a solid state devise called a driver. The ECM monitors the status of the driver. If the ECM detects an incorrect voltage for the commanded state of the driver, a MAF sensor supply voltage control circuit DTC is set.