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Home >> Lexus >> 2007 >> GS 450h >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - Component And System Testing, On-Vehicle Inspection, Removal, Inspection & Installation >> ECM Power Source Circuit >> Inspection Procedure
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Inspection Procedure

  1. CHECK HARNESS AND CONNECTOR (INTEGRATION RELAY - BODY GROUND) 
    1. Remove the integration relay from the engine room No. 1 junction block.
    2. Measure the voltage between the terminal of the wire harness side connector and body ground.

      Standard voltage 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester Connection Specified Condition
      Engine room No. 1 junction block (1R-1) - Body ground 9 to 14 V
    3. Reinstall the integration relay.
      Fig 1: Identifying Integration Relay
      G05302492Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR (INTEGRATION RELAY BATTERY) 

    OK: GO TO Next Step 

  2. INSPECT INTEGRATION RELAY (EFI MAIN RELAY) 
    1. Remove the integration relay (Unit A) from the engine room No. 1 junction block.
    2. Inspect the EFI fuse.
      1. Remove the EFI fuse from the integration relay.
      2. Measure the resistance of the EFI fuse.

        Standard resistance: 

        Below 1 Ω 

      3. Reinstall the EFI fuse.
    3. Inspect the EFI MAIN relay.
      1. Measure the resistance of the EFI MAIN relay.

        Standard resistance 

        TESTER CONNECTION SPECIFIED CONDITION CHART

        Tester Connection Specified Condition
        1R-1 - 1T-8 10 kΩ or higher
        Below 1 Ω (Apply battery voltage between terminals 1T-6 and 1T-7)
    4. Reinstall the integration relay.
      Fig 2: Identifying EFI Main Relay
      G05302493Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPLACE INTEGRATION RELAY 

    OK: GO TO Next Step 

  3. CHECK HARNESS AND CONNECTOR (+B, +B1 AND MREL CIRCUIT) 
    1. Check the harness and the connectors between the integration relay and the ECM.
      1. Remove the integration relay (Unit A) from the engine room No. 1 junction block.
      2. Disconnect the A53 ECM connector.
      3. Measure the resistance between the terminals of the wire harness side connectors.

        Standard resistance (Check for open) 

        TESTER CONNECTION SPECIFIED CONDITION CHART

        Tester Connection Specified Condition
        MREL (A53-12) - Engine room No. 1 Junction block (1T-6) Below 1 Ω
        +B (A53-2) - Engine room No. 1 junction block (1T-8)
        +B1 (A53-1) - Engine room No. 1 junction block (1T-8)

        Standard resistance (Check for short) 

        TESTER CONNECTION SPECIFIED CONDITION CHART

        Tester Connection Specified Condition
        MREL (A53-12) or Engine room No. 1 junction block (1T-6) - Body ground 10 kΩ or higher
        +B (A53-2) or Engine room No. 1 junction block (1T-8) - Body ground
        +B1 (A53-1) or Engine room No. 1 junction block (1T-8) - Body ground
    2. Check the harness and the connectors between the integration relay and body ground.
      1. Measure the resistance between the terminals of the wire harness side connector and body ground.

        Standard resistance (Check for open) 

        TESTER CONNECTION SPECIFIED CONDITION CHART

        Tester Connection Specified Condition
        Engine room No. 1 junction block (1T-7) - Body ground Below 1 Ω
    3. Reinstall the integration relay.
    4. Reconnect the ECM connector.
      Fig 3: Identifying Integration Relay
      G05302494Courtesy 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 E83 ECM connector.
    2. Measure the resistance.

      Standard resistance (Check for open) 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester Connection Specified Condition
      E1 (E83-104) - Body ground Below 1 Ω
    3. Reconnect the ECM connector.
      Fig 4: Identifying E83 ECM Connector
      G05302495Courtesy 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 E83 and A53 ECM connectors.
    2. Turn the power switch ON (IG).
    3. Measure the voltage between the terminals of the ECM connectors.

      Standard voltage 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester Connection Specified Condition
      IGSW (A53-11) - E1 (E83-104) 9 to 14 V
    4. Reconnect the ECM connectors.
      Fig 5: Identifying E83 And A53 ECM Connectors
      G05302496Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    OK: REPLACE ECM 

    NG: GO TO Next Step 

  6. INSPECT FUSE (IGN AND IG2 MAIN FUSE) 
    1. Remove the IGN fuse from the main body ECU (cowl side junction block RH).
      Fig 6: Identifying IGN Fuse
      G05302497Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Remove the IG2 MAIN fuse from the engine room No. 1 relay block.
    3. Measure the resistance of the IGN and IG2 MAIN fuse.

      Standard resistance: 

      Below 1 Ω 

      Fig 7: Identifying IG2 Main Fuse
      G05302498Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

    OK: GO TO Next Step 

  7. INSPECT IG2 RELAY 
    1. Remove the IG2 relay from the engine room No. 1 relay block.
    2. Measure the resistance of the IG2 relay.

      Standard resistance 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester Connection Specified Condition
      3 - 5 10 kΩ or higher
      3 - 5 Below 1 Ω (When battery voltage applied to terminals 1 and 2)
    3. Reinstall the relay.
      Fig 8: Inspecting EFI Relay
      G04942976Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPLACE IG2 RELAY 

    OK: GO TO Next Step 

  8. CHECK HARNESS AND CONNECTOR (ECM - IG2 RELAY) 
    1. Remove the IG2 relay from the engine room No. 1 relay block.
    2. Disconnect the A53 ECM connector.
    3. Measure the resistance between the terminal of the wire harness side connectors.

      Standard resistance (Check for open) 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester Connection Specified Condition
      Relay block IG2 relay terminal (3) - IGSW (A53-11) Below 1 Ω

      Standard resistance (Check for short) 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester Connection Specified Condition
      Relay block IG2 relay terminal (3) or IGSW (A53-11) - Body ground 10 KΩ or higher
      Fig 9: Identifying IG2 Relay
      G05302500Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: GO TO Next Step 

  9. CHECK HARNESS AND CONNECTOR (ENGINE ROOM NO. 1 RELAY BLOCK - POWER SOURCE CONTROL ECU) 
    1. Remove the IG2 relay from the engine room No. 1 relay block.
    2. Disconnect the K73 power source control ECU connector.
    3. Measure the resistance between the terminal of the wire harness side connectors.

      Standard resistance (Check for open) 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester Connection Specified Condition
      Relay block IG2 relay terminal (2) - IG2D (K73-35) Below 1 Ω
      Relay block IG2 relay terminal (1) - Body ground Below 1 Ω

      Standard resistance (Check for short) 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester Connection Specified Condition
      IG2D (K73-35) - Body ground 10 kΩ or higher
      Fig 10: Identifying IG2 Relay
      G05302501Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    OK: CHECK ENTRY AND START SYSTEM 

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

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