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Home >> Scion >> 2008 >> tC Base, Automatic >> Repair and Diagnosis >> Engine Performance >> Remove, Overhaul & Install >> 2AZ-FE Engine Control System >> SFI System >> DTC P0100: Mass or Volume Air Flow Circuit; DTC P0102: Mass or Volume Air Flow Circuit Low Input; DTC P0103: Mass or Volume Air Flow Circuit High Input >> Inspection Procedure

Inspection Procedure

HINT:

Read freeze frame data using the intelligent tester. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can be helpful in determining whether the vehicle was running or stopped, whether the engine was warmed up or not, whether the air-fuel ratio was lean or rich, as well as other data recorded at the time of a malfunction.

  1. READ VALUE USING INTELLIGENT TESTER (MASS AIR FLOW RATE) 
    1. Connect the intelligent tester to the DLC3.
    2. Start the engine.
    3. Turn the tester on.
    4. On the tester, select the following menu items: DIAGNOSIS / ENHANCED OBD II / DATA LIST / ALL / MAF.
    5. Read the values displayed on the tester.

      Result 

      DTC OUTPUT RESULT

      Mass Air Flow Rate (gm/s) Proceed to
      0.0 A
      271.0 or more B
      Between 1.0 and 270.0 (*) C
      HINT:
      *: The value must change when the throttle valve is opened or closed.

    B:  Go to step  6

    C: CHECK FOR INTERMITTENT PROBLEMS 

    A: Go to next step 

  2. INSPECT MASS AIR FLOW METER (POWER SOURCE VOLTAGE) 
    1. Disconnect the M1 MAF meter connector.
      2. Fig 1: Identifying M1 MAF Meter Connector
      G05538956Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Turn the ignition switch to the ON position.
    3. Measure the voltage according to the value(s) in the table below.

      Standard voltage 

      VOLTAGE SPECIFIED CONDITION

      Tester Connection Specified Condition
      +B (M1-3) - Body ground 9 to 14 V

    NG:  Go to step  5

    OK: Go to next step 

  3. INSPECT ECM (VG VOLTAGE) 
    1. Start the engine.
    2. Measure the voltage according to the value(s) in the table below.

      HINT:

      The transmission gear selector lever should be in the P or N position and the A/C switch should be turned off.

      Standard voltage 

      VOLTAGE SPECIFIED CONDITION

      Tester Connection Condition Specified Condition
      VG (E7-28) - E2G (E7-30) Engine idling 0.5 to 3.0 V
      Fig 2: Identifying EG2 And VG Terminal Of ECM Connector
      G05538957Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: Go to step 4 

    OK: REPLACE ECM  (See REMOVAL  )

  4. CHECK WIRE HARNESS (MASS AIR FLOW METER - ECM) 
    1. Disconnect the M1 MAF meter connector.
      Fig 3: Identifying E2G And VG Terminal Of MAF Meter Connector
      G05538958Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Disconnect the E7 ECM connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard resistance 

      RESISTANCE SPECIFIED CONDITIONS

      Tester Connection Specified Condition
      VG (M1-5) - VG (E7-28) Below 1 Ω
      E2G (M1-4) - E2G (E7-30) Below 1 Ω
      VG (M1-5) or VG (E7-28) - Body ground 10 kΩ or higher
      Fig 4: Identifying E2G And VG Terminal Of ECM Connector
      G05538959Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: REPLACE MASS AIR FLOW METER 

  5. CHECK WIRE HARNESS (MASS AIR FLOW METER - EFI RELAY [Marking: EFI]) 
    1. Inspect the EFI fuse.
      1. Remove the EFI fuse from the engine room relay block.
        2. Fig 5: Identifying EFI Relay, EFI Fuse And MAF Meter Connector
        G05538960Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      2. Measure the EFI fuse resistance.

        Standard resistance: 

        Below 1 Ω 

      3. Reinstall the EFI fuse.
    2. Remove the EFI relay from the engine room relay block.
    3. Disconnect the M1 MAF meter connector.
    4. Measure the resistance according to the value(s) in the table below.

      Standard resistance 

      RESISTANCE SPECIFIED CONDITIONS

      Tester Connection Specified Condition
      +B (M1-3) - EFI relay(3) Below 1 Ω
      +B (M1-3) or EFI relay (3) - Body ground 10 kΩ or higher

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: INSPECT ECM POWER SOURCE CIRCUIT 

  6. INSPECT ECM (SENSOR GROUND) 
    1. Measure the resistance according to the value(s) in the table below.

      Standard resistance 

      RESISTANCE SPECIFIED CONDITIONS

      Tester Connection Specified Condition
      E2G (E7-30) - Body ground Below 1 Ω
      Fig 6: Identifying E2G Terminal Of ECM Connector
      G05538961Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPLACE ECM  (See REMOVAL  )

    OK: Go to next step 

  7. CHECK WIRE HARNESS (MASS AIR FLOW METER - ECM) 
    1. Disconnect the M1 MAF meter connector.
      Fig 7: Identifying E2G And VG Terminal Of MAF Connector
      G05538958Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Disconnect the E7 ECM connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard resistance 

      RESISTANCE SPECIFIED CONDITIONS

      Tester Connection Specified Condition
      VG (M1-5) - VG (E7-28) Below 1 Ω
      E2G (M1-4) - E2G (E7-30) Below 1 Ω
      VG (M1-5) or VG (E7-28) - Body ground 10 kΩ or higher
      Fig 8: Identifying E2G And VG Terminal Of ECM Connector
      G05538959Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: REPLACE MASS AIR FLOW METER 

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