AIR FLOW SENSOR

Description:

The mass air flow sensor is placed in the stream of intake air. It converts the amount of air drawn into the engine into a voltage signal, The ECM need to know intake air volume to calculate engine load. This is necessary to determine how much fuel to inject, when to ignite the cylinder, an when to shift the transmission.

There are different types of Air Flow Meter (Air Flow Sensor, Mass Air Flow Sensor), but the more common is the Mass Air Flow (MAF) sensor.

It consists of a hot film that is supplied with electric current from the ECM. The temperature of the hot film is controlled by the ECM a certain amount. The heat generated by the hot film is reduced as the intake air flows around it. The more air, the greater the heat loss. Therefore, the ECM must supply more electric current to maintain the temperature of the hot film as air flow increases. The ECM detects the air flow by means of this current change.

Typical Wire Diagram:

Component Diagnoses:

Diagnosis the MAF sensor involves visual, circuit, and component check.  The MAF sensor passage must be free of debris to operate properly. If the passage is plugged, the engine will usually start, but run poorly or stall and may not set a DTC.

Component Inspection:

It depends on the manufacture.