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Home >> Scion >> 2009 >> tC 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 Techstream. 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 TECHSTREAM (MASS AIR FLOW RATE) 
    1. Connect the Techstream to the DLC3.
    2. Start the engine.
    3. Turn the Techstream on.
    4. On the Techstream, select the following menu items: Powertrain/Engine and ECT/Data List/All Data/MAF.
    5. Read the values displayed on the Techstream.

      Result 

      RESULT CHART

      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 (See  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. Turn the ignition switch to the ON position.
    3. Measure the voltage according to the value(s) in the table below.

      Standard voltage 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester Connection Specified Condition
      +B (M1-3) - Body ground 9 to 14 V
    4. Reconnect the MAF meter connector.

    NG: Go to step  5

    OK: Go to next step 

    Fig 1: Identifying M1 MAF Meter Connector Terminals
    G05538956Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  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 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester Connection Condition Specified Condition
      VG (E7-28) - E2G (E7-30) Engine idling 0.5 to 3.0 V

    NG: Go to step 4 

    OK: REPLACE ECM  (See REMOVAL )

    Fig 2: Identifying E7 ECM Connector Terminals
    G05538957Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  4. CHECK WIRE HARNESS (MASS AIR FLOW METER - ECM) 
    1. Disconnect the M1 MAF meter connector.
      Fig 3: Identifying M1 MAF Meter Connector Terminals
      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 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      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
    4. Reconnect the MAF meter connector.
    5. Reconnect the ECM connector.
    Fig 4: Disconnecting E7 ECM Connector
    G05538959Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: REPLACE MASS AIR FLOW METER  (See REMOVAL )

  5. CHECK WIRE HARNESS (MASS AIR FLOW METER - EFI RELAY) 
    1. Inspect the EFI fuse.
      1. Remove the EFI fuse from the engine room relay block.
      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 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      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
    5. Reinstall the EFI relay.
    6. Reconnect the MAF meter connector.

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: INSPECT ECM POWER SOURCE CIRCUIT  (See ECM POWER SOURCE CIRCUIT )

    Fig 5: Identifying EFI Relay, EFI Fuse And MAF Meter Connector
    G05538960Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  6. INSPECT ECM (SENSOR GROUND) 
    1. Measure the resistance according to the value(s) in the table below.

      Standard resistance 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester Connection Specified Condition
      E2G (E7-30) - Body ground Below 1 Ω

    NG: REPLACE ECM  (See REMOVAL )

    OK: Go to next step 

    Fig 6: Identifying E7 ECM Connector Terminals
    G05538961Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  7. CHECK WIRE HARNESS (MASS AIR FLOW METER - ECM) 
    1. Disconnect the M1 MAF meter connector.
      Fig 7: Identifying M1 MAF Meter Connector Terminals
      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 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      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
    4. Reconnect the MAF meter connector.
    5. Reconnect the ECM connector.

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: REPLACE MASS AIR FLOW METER  (See REMOVAL )

    Fig 8: Disconnecting E7 ECM Connector
    G05538959Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
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