Air Flow Meter/Sensor: Testing and Inspection

Mass Air Flow Sensor Circuit:

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

- Remove ECM with bracket, relays, fuse box and wire harness.
- Connect couplers to ECM.

Mass Air Flow Sensor Power Supply Terminal:

- Connect voltmeter to "B+" terminal of MAF sensor coupler disconnected and ground.
- Turn ignition switch ON and check that there is battery voltage.
- If not, check if wire harness is open or connection is poor.
- Turn ignition switch OFF and connect MAF sensor coupler to MAF sensor.

Mass Air Flow Sensor Signal Terminal:

- Turn ignition switch ON and check voltage (Is) at "B8" terminal.

Is voltage 1.O - 1.6 V

- Start engine and check that voltage is lower than 5V and it rises as engine speed increases.

Reference data 1.7 - 2.0V at specified idle speed

- If check result is not as specified above, cause may lie in wire harness, coupler connection, MAF sensor or ECM.