Air Flow Meter/Sensor: Testing and Inspection

MASS AIR FLOW SENSOR (MAF SENSOR)

CAUTION:
Do not remove MAF sensor from throttle body.
Malfunction may occur.

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

INSPECTION

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




1. Remove ECM, referring to ECM removal.
2. Connect couplers to ECM.




3. Connect voltmeter to "R/B" wire terminal of MAF sensor coupler 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 coupler to MAF sensor.
6. Turn ignition switch ON and check voltage at "C20-24" terminal.
"Standard" voltage: 0.5 - 1.0 V
7. Start engine and check that voltage is lower than 5 V and it rises as engine speed increases.
(Reference data: 1.3 - 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.