Mass Air Flow (MAF) Sensor On-Vehicle Inspection

1. Connect voltmeter (1) to "B+" terminal of MAF sensor (2) coupler disconnected and ground (3).
   Fig 1: Connect Voltmeter To Ground & "B+" Terminal Of MAF Sensor

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2. Turn ignition switch ON and check that voltage is battery voltage. If not, check if wire harness is open or connection is poor.
3. Turn ignition switch OFF and remove ECM (PCM) cover (1) from bracket.
   Fig 2: Removing ECM (PCM) Cover

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4. Connect MAF sensor coupler to MAF sensor.
5. Turn ignition switch ON and check voltage at MAF sensor output terminal of ECM (PCM) connector (1).

   MAF sensor output voltage 

   1. Voltage:  1.0 - 1.6V
   Fig 3: Checking Voltage At MAF Sensor Output Terminal Of ECM (PCM) Connector

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

(Reference data: 1.7 - 2.0 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).