Air Flow Meter/Sensor: Testing and Inspection

Mass Air Flow (MAF) Sensor On-Vehicle Inspection

NOTE: Use voltmeter with high-impedance (10 kOhm/V minimum) or digital type voltmeter.

1. Remove ECM (PCM) cover from bracket.




2. With ignition switch OFF, disconnect MAF sensor connector (1 ).
3. Connect voltmeter to C32-3 terminal (2) of MAF sensor connector (1) disconnected and ground.
4. Turn ignition switch ON and check that voltage is battery voltage.
If not, check if wire harness is open or connection is poor.
5. Turn ignition switch OFF and connect MAF sensor connector to MAF sensor.

6. Turn ignition switch ON and check voltage between C51-3-23 and C51-3-20 terminal.

Voltage between C51-3-23 and C51-3-20 terminal 0.5 - 1.0 V

7. Start engine and check that voltage is lower than 5V and it rises as engine speed increases.
(Reference data: 1.5 - 1.8 V at specified idle speed)
If check result is not as specified above, cause may lie in wire harness, coupler connection, MAF sensor or ECM (PCM).




Terminal arrangement of ECM (PCM) connector (viewed from harness side)