Air Flow Meter/Sensor: Testing and Inspection

MASS AIR FLOW SENSOR (MAFS)




DESCRIPTION
The Mass Air Flow Sensor (MAFS) is located between the air cleaner assembly and the throttle body. The MAFS uses a hot film type sensing element to measure the mass of intake air entering the engine. Mass air flow rate is measured by detecting of heat transfer from a hot film probe. The change in air flow rate causes change in the amount of heat being transferred from the hot film probe surface to the air. A large amount of intake air represents acceleration or high load conditions while a small amount of Intake air represents deceleration or idle. The ECM uses this information to determine the injection duration and ignition timing for the desired air/fuel ratio.

Circuit Diagram:

CIRCUIT DIAGRAM

Waveform:

WAVEFORM

HARNESS INSPECTION
Refer to DTC P0102 and P0103 troubleshooting procedures.

SENSOR INSPECTION
1. Run the engine and connect Hi-Scan (Pro) to data link connector.




2. Check if sensor output is normal using Hi-Scan (Pro).