Air Flow Meter/Sensor: Testing and Inspection

Mass Air Flow (MAF) Sensor On-Vehicle Inspection

CAUTION: Do not remove MAF sensor (2) from throttle body (1). Malfunction may occur.

NOTE: Whenever MAF sensor replacement is necessary, replace throttle body equipped with MAF sensor with new one.

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




1. Remove ECM, referring to "Engine Control Module (ECM) Removal and Installation".
2. Connect couplers to ECM.
3. Connect voltmeter to "R/B" wire terminal (3) of MAF sensor coupler (1) disconnected and ground (2).




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 coupler to MAF sensor.




6. Turn ignition switch ON and check voltage at "C20-24" terminal.

Voltage between "C20-24" terminal and ground
Standard: 0.5 - 1.0 V

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

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

Reference voltage
1.3 - 1.8 V at specified idle speed