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Home >> Toyota >> 2007 >> Tundra Base, 4.0 U >> Repair and Diagnosis >> Engine Performance >> Engine Control Systems >> Engine Control System (1GR-FE) - System Testing, On-Vehicle Inspection, Removal, Inspection & Installation >> ECM Power Source Circuit >> Inspection Procedure
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Inspection Procedure

  1. INSPECT INTEGRATION RELAY (INTEGRATION RELAY - BODY GROUND) 
    1. Remove the integration relay from the engine room junction block (see ON-VEHICLE INSPECTION  ).
    2. Measure the voltage according to the value(s) in the table below.

      Standard voltage 

      INTEGRATION RELAY - BODY GROUND VOLTAGE

      Tester Connection Condition Specified Condition
      1C-1 - Body ground Always 11 to 14 V
      Fig 1: Inspecting Integration Relay (Integration Relay - Body Ground)
      G05149509Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  2. INSPECT INTEGRATION RELAY (EFI RELAY AND IG2 RELAY) 
    1. Remove the integration relay from the engine room relay block (see ON-VEHICLE INSPECTION  ).
    2. Inspect the EFI NO. 1 fuse and the IG2 MAIN fuse.
      1. Remove the EFI NO. 1 fuse and IG2 MAIN fuse from the integration relay.
      2. Measure the resistance according to the value(s) in the table below.

        Standard resistance 

        EFI NO. 1 FUSE AND THE IG2 MAIN FUSE

        Tester Connection Condition Specified Condition
        EFI NO. 1 fuse Always Below 1 Ω
        IG2 MAIN fuse Always Below 1 Ω
        Fig 2: Inspecting Integration Relay (EFI Relay And IG2 Relay)
        G05149510Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    3. Inspect the EFI relay and the IG2 relay.
      1. Measure the resistance according to the value(s) in the table below.

        Standard resistance 

        EFI RELAY AND THE IG2 RELAY

        Tester Connection Condition Specified Condition
        1C-1 - 1B-4 When no battery voltage is applied to terminals 1B-2 and 1B-3 10 kΩ or higher
        When battery voltage is applied to terminals 1B-2 and 1B-3 Below 1 Ω
        1C-1 - 1B-8 When no battery voltage is applied to terminals 1B-7 and 1B-6 10 kΩ or higher
        When battery voltage is applied to terminals 1B-7 and 1B-6 Below 1 Ω

    NG: REPLACE INTEGRATION RELAY  (see ON-VEHICLE INSPECTION  )

    OK: Go to next step 

  3. CHECK HARNESS AND CONNECTOR (+B, +B2 AND MREL CIRCUIT) 
    1. Check the harness and the connectors between the integration relay and the ECM.
      1. Remove the integration relay from the engine room junction block (see ON-VEHICLE INSPECTION  ).
      2. Disconnect the A24 ECM connector.
      3. Measure the resistance according to the value(s) in the table below.

        Standard resistance (Check for open) 

        INTEGRATION RELAY AND ECM (CHECK FOR OPEN)

        Tester Connection Condition Specified Condition
        A24-34 (MREL) - 1B-2 Always Below 1 Ω
        A24-3 (+B) - 1B-4 Always Below 1 Ω
        A24-2 (+B2) - 1B-4 Always Below 1 Ω

        Standard resistance (Check for short) 

        INTEGRATION RELAY AND ECM (CHECK FOR SHORT)

        Tester Connection Condition Specified Condition
        A24-34 (MREL) or 1B-2 - Body ground Always 10 kΩ or higher
        A24-3 (+B) or 1B-4 - Body ground Always 10 kΩ or higher
        A24-2 (+B2) or 1B-4 - Body ground Always 10 kΩ or higher
    2. Check the harness and connectors between the integration relay and body ground.
      1. Measure the resistance according to the value(s) in the table below.

        Standard resistance (Check for open) 

        INTEGRATION RELAY AND BODY GROUND

        Tester Connection Condition Specified Condition
        1B-3 - Body ground Always Below 1 Ω
        Fig 3: Checking Harness And Connector (+B, +B2 And MREL Circuit)
        G05149511Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  4. CHECK HARNESS AND CONNECTOR (ECM - BODY GROUND) 
    1. Disconnect the D74 ECM connector.
    2. Measure the resistance according to the value(s) in the table below.

      Standard resistance (Check for open) 

      ECM - BODY GROUND

      Tester Connection Condition Specified Condition
      D74-81 (E1) - Body ground Always Below 1 Ω
      Fig 4: Identifying D74 Connector Terminals
      G05149512Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  5. INSPECT ECM (IGSW VOLTAGE) 
    1. Disconnect the D74 and A24 ECM connectors.
    2. Measure the voltage according to the value(s) in the table below.

      Standard voltage 

      ECM (IGSW VOLTAGE)

      Tester Connection Switch Condition Specified Condition
      A24-28 (IGSW) - D74-81 (El) Ignition switch ON 11 to 14 V
      Fig 5: Identifying D74 And A24 Connectors Terminals
      G05149513Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: Go to step 6 

    OK: REPLACE ECM  (see REMOVAL  )

  6. INSPECT FUSE (IGN) 
    1. Remove the IGN fuse from the engine room relay block.
    2. Measure the resistance according to the value(s) in the table below.

      Standard resistance (Check for open) 

      FUSE (IGN)

      Tester Connection Condition Specified Condition
      IGN fuse Always Below 1 Ω
      Fig 6: Identifying IGN Fuse
      G05149514Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: CHECK FOR SHORT IN ALL HARNESSES AND CONNECTORS CONNECTED TO FUSE AND REPLACE FUSE 

    OK: Go to next step 

  7. CHECK HARNESS AND CONNECTOR (INTEGRATION RELAY - ECM, INTEGRATION RELAY - BODY GROUND) 
    1. Remove the integration relay from the engine room junction block (see ON-VEHICLE INSPECTION  ).
    2. Disconnect the A24 ECM connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard resistance (Check for open) 

      INTEGRATION RELAY - ECM, INTEGRATION RELAY - BODY GROUND (CHECK FOR OPEN)

      Tester Connection Condition Specified Condition
      1B-8-A24-28 (IGSW) Always Below 1 Ω

      Standard resistance (Check for short) 

      INTEGRATION RELAY - ECM, INTEGRATION RELAY - BODY GROUND (CHECK FOR SHORT)

      Tester Connection Condition Specified Condition
      1B-8 or A24-28 (IGSW) - Body ground Always 10 kΩ or higher
      Fig 7: Checking Harness And Connector (Integration Relay - ECM, Integration Relay - Body Ground)
      G05149515Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  8. CHECK HARNESS AND CONNECTOR (INTEGRATION RELAY - IGNITION SWITCH ASSEMBLY) 
    1. Check the harness and the connectors between the integration relay and the ignition switch.
      1. Remove the integration relay from the engine room junction block (see ON-VEHICLE INSPECTION  ).
      2. Disconnect the J9 ignition switch connector.
      3. Measure the resistance according to the value(s) in the table below.

        Standard resistance (Check for open) 

        INTEGRATION RELAY AND IGNITION SWITCH (CHECK FOR OPEN)

        Tester Connection Condition Specified Condition
        1B-6 - J9-6 (IG2) Always Below 1 Ω

        Standard resistance (Check for short) 

        INTEGRATION RELAY AND IGNITION SWITCH (CHECK FOR SHORT)

        Tester Connection Condition Specified Condition
        1B-6 or J9-6 (IG2) - Body ground Always 10 kΩ or higher
    2. Check the harness and connectors between the integration relay and body ground.
      1. Measure the resistance according to the value(s) in the table below.

        Standard resistance (Check for open) 

        INTEGRATION RELAY AND BODY GROUND

        Tester Connection Condition Specified Condition
        1B-7 - Body ground Always Below 1 Ω
        Fig 8: Checking Harness And Connector (Integration Relay - Ignition Switch Assembly)
        G05149516Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  9. INSPECT IGNITION SWITCH ASSEMBLY 
    1. Disconnect the J9 ignition switch connector.
    2. Measure the resistance according to the value(s) in the table below.

      Standard resistance 

      IGNITION SWITCH ASSEMBLY

      Tester Connection Switch Condition Specified Condition
      All Terminals Ignition switch position LOCK 10 kΩ or higher
      2 (ACC) - 4 (AM1) Ignition switch position ACC Below 1 Ω
      1 (IG1) - 2 (ACC) - 4 (AM1) Ignition switch position ON
      5 (AM2) - 6 (IG2)
      1 (IG1) - 3 (ST1) - 4 (AM1) Ignition switch position START
      5 (AM2) - 6 (IG2) - 7 (ST2)
      Fig 9: Identifying J9 Ignition Switch Connector Terminals
      G05149428Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPLACE IGNITION SWITCH ASSEMBLY  (See REMOVAL )

    OK: REPAIR OR REPLACE HARNESS OR CONNECTOR 

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