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Home >> Toyota >> 2007 >> Avalon XL >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - System And Circuit Testing, On-Vehicle Inspection, Removal, Inspection And Installation >> ECM Power Source Circuit >> Inspection Procedure
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Inspection Procedure

  1. INSPECT ECM (+B VOLTAGE) 
    1. Turn the ignition switch on (IG).
    2. Measure the voltage between the terminals of the ECM connectors.

      Standard voltage 

      TESTER CONNECTION SPECIFIED CONDITION

      Tester Connections Specified Conditions
      +B(A24-1) - E1(B47-1) 9 to 14 V
      +B2 (A24-2) - E1 (B47-1) 9 to 14 V
    Fig 1: Identifying ECM Connector Terminals
    G04996496Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

    OK: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN  PROBLEM SYMPTOMS TABLE 

    NG: Go to Next Step 

  2. CHECK HARNESS AND CONNECTOR (ECM - BODY GROUND) 
    1. Disconnect the ECM connector.
    2. Measure the resistance between the terminal of the ECM connector and body ground.

      Standard resistance (Check for open) 

      TESTER CONNECTION SPECIFIED CONDITION

      Tester Connections Specified Conditions
      E1 (B47-1) - Body ground Below 1 Ω
    3. Reconnect the ECM connector.
    Fig 2: Identifying ECM Connector Terminal
    G04996497Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to Next Step 

  3. INSPECT ECM (IGSW VOLTAGE) 
    1. Turn the ignition switch on (IG).
    2. Measure the voltage between the terminals of the ECM connectors.

      Standard voltage 

      TESTER CONNECTION SPECIFIED CONDITION

      Tester Connections Specified Conditions
      IGSW (A24-9) - E1 (B47-1) 9 to 14 V
    Fig 3: Identifying ECM Connector Terminals
    G04996498Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

    OK:  Go to step  6

    NG: Go to Next Step 

  4. CHECK FUSE (IGN FUSE) 
    1. Remove the IGN fuse from the instrument panel J/B.
    2. Measure the IGN fuse resistance.

      Standard resistance: 

      Below 1 Ω 

    3. Reinstall the IGN fuse.
    Fig 4: Identifying IGN Fuse Location
    G04996499Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

    NG: REPLACE FUSE (IGN FUSE) 

    OK: Go to Next Step 

  5. INSPECT IGNITION OR STARTER SWITCH ASSEMBLY 
    1. Inspect the ignition or starter switch assembly (See IGNITION SWITCH (W/O SMART KEY SYSTEM) ).

    NG: REPLACE IGNITION OR STARTER SWITCH ASSEMBLY 

    OK: Go to Next Step 

  6. INSPECT ECM (MREL VOLTAGE) 
    1. Turn the ignition switch on (IG).
    2. Measure the voltage between the terminals of the ECM connectors.

      Standard voltage 

      TESTER CONNECTION SPECIFIED CONDITION

      Tester Connections Specified Conditions
      MREL (A24-8) - E1(B47-1) 9 to 14 V
    Fig 5: Identifying ECM Connector Terminals
    G04996500Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

    NG: REPLACE ECM 

    OK: Go to Next Step 

  7. CHECK FUSE (EFI NO. 1 FUSE) 
    1. Remove the EFI No. 1 fuse from the engine room R/B and J/B.
    2. Measure the EFI No. 1 fuse resistance.

      Standard resistance: 

      Below 1 Ω. 

    3. Reinstall the EFI No. 1 fuse.
    Fig 6: Identifying EFI Fuse Location
    G04996501Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

    NG: REPLACE FUSE (EFI NO. 1 FUSE) 

    OK: Go to Next Step 

  8. INSPECT ENGINE ROOM JUNCTION BLOCK ASSEMBLY (EFI RELAY) 
    1. Remove the engine room junction block.
    2. Measure the EFI relay resistance.

      Standard resistance 

      TESTER CONNECTION SPECIFIED CONDITION

      Tester Connections Specified Conditions
      1D-4 - 1D-6 10 kΩ or higher
      1D-4 - 1D-6 Below 1 Ω (when battery voltage applied to terminals 1H-10 and 1H-2)
    3. Reinstall the engine room junction block.
    Fig 7: Identifying Engine Room Junction Block Connector Terminals
    G04996502Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

    NG: REPLACE ENGINE ROOM JUNCTION BLOCK ASSEMBLY 

    OK: Go to Next Step 

  9. CHECK HARNESS AND CONNECTOR (EFI RELAY - ECM, EFI RELAY - BODY GROUND) 
    1. Check the harness and connector between the EFI relay and ECM.
      1. Remove the engine room junction block.
      2. Disconnect the ECM connector.
      3. Measure the resistance according to the value(s) in the table below.

      Standard resistance (Check for open) 

      TESTER CONNECTION SPECIFIED CONDITION

      Tester Connections Specified Conditions
      Engine room junction block (EFI relay) (1H-10) - MREL (A24-8) Below 1 Ω

      Standard resistance (Check for short) 

      TESTER CONNECTION SPECIFIED CONDITION

      Tester Connections Specified Conditions
      Engine room junction block (EFI relay) (1H-10) or MREL (A24-8) - Body ground 10 kΩ or higher
    2. Check the harness and connector between the engine room junction block (EFI relay) and body ground.
      1. Measure the resistance between the terminal of the engine room junction block (EFI relay) and body ground.

        Standard resistance (Check for open) 

        TESTER CONNECTION SPECIFIED CONDITION

        Tester Connections Specified Conditions
        Engine room junction block (EFI relay) (1H-2) - Body ground Below 1 Ω
      2. Reinstall the engine room junction block.
      3. Reconnect the ECM connector.
    Fig 8: Identifying Engine Room Junction Block And ECM Connector Terminals
    G04996503Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

    OK: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    NG: CHECK AND REPLACE HARNESS AND CONNECTOR (TERMINAL +B OF ECM - BATTERY POSITIVE TERMINAL) 

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