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ECM Power Source Circuit: Procedure

  1. INSPECT INTEGRATION RELAY (POWER SOURCE) 
    1. Remove the integration relay from the engine room relay block.
      Fig 1: Identifying Engine Room Relay Block Connector Terminal
      GTY290542Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Disconnect the integration relay connector.
    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      1E-1 - Body ground Always 11 to 14 V
    4. Reconnect the integration relay connector.
    5. Reinstall the integration relay.

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR (INTEGRATION RELAY - BATTERY) 

    OK: Go to next step 

  2. INSPECT FUSES (EFI MAIN, IG2, AND EFI NO. 1 FUSES) 
    1. Remove the EFI MAIN fuse, IG2 fuse and EFI No. 1 fuse from the engine room relay block.
      Fig 2: Identifying Engine Room Relay Block
      GTY230594Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      EFI MAIN fuse Always Below 1 Ω
      IG2 fuse
      EFI No. 1 fuse
    3. Reinstall the fuses.

    NG → REPLACE FUSE (EFI MAIN, IG2 OR EFI NO. 1 FUSE) 

    OK: Go to next step 

  3. INSPECT INTEGRATION RELAY (EFI MAIN RELAY AND IG2 RELAY) 
    1. Inspect the integration relay. Refer to INSPECTION .

    NG → See step   13 

    OK: Go to next step 

  4. CHECK HARNESS AND CONNECTOR (INTEGRATION RELAY - ECM) 
    1. Remove the integration relay from the engine room relay block.
    2. Disconnect the integration relay connector.
    3. Disconnect the ECM connector.
    4. Measure the resistance according to the value(s) in the table below.

      Standard Resistance (Check for Open)

      Tester Connection Condition Specified Condition
      A37-44 (MREL) - 1B-2 Always Below 1 Ω
      A37-2 (+B) - 1B-4 Always Below 1 Ω
      A37-1 (+B2) - 1B-4 Always Below 1 Ω

      Standard Resistance (Check for Short)

      Tester Connection Condition Specified Condition
      A37-44 (MREL) or 1B-2 - Body ground Always 10 kΩ or higher
    5. Reconnect the integration relay connector.
    6. Reinstall the integration relay.
    7. Reconnect the ECM connector.

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR (INTEGRATION RELAY - ECM) 

    OK: Go to next step 

  5. CHECK HARNESS AND CONNECTOR (INTEGRATION RELAY - BODY GROUND) 
    1. Remove the integration relay from the engine room relay block.
    2. Disconnect the integration relay connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance (Check for Open)

      Tester Connection Condition Specified Condition
      1A-3 - Body ground Always Below 1 Ω
      1B-3 - Body ground Always Below 1 Ω
    4. Reconnect the integration relay connector.
    5. Reinstall the integration relay.

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR (INTEGRATION RELAY - BODY GROUND) 

    OK: Go to next step 

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

      Standard Resistance (Check for Open)

      Tester Connection Condition Specified Condition
      B29-104 (E1) - Body ground Always Below 1 Ω
    3. Reconnect the ECM connector.

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR (ECM - BODY GROUND) 

    OK: Go to next step 

  7. INSPECT ECM (IGSW TERMINAL VOLTAGE) 
    1. Disconnect the ECM connectors.
      Fig 3: Identifying ECM Wiring Harness Connector
      GTY320464Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Turn the ignition switch to ON.
    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      A37-28 (IGSW) - B29-104 (E1) Ignition switch ON 11 to 14 V
    4. Reconnect the ECM connectors.

    NG → See step   8 

    OK → See step   14 

  8. INSPECT FUSE (IGN FUSE) 
    1. Remove the IGN fuse from the driver side junction block.
      Fig 4: Identifying IGN Fuse
      GTY215238Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      IGN fuse Always Below 1 Ω
    3. Reinstall the IGN fuse.

    NG → REPLACE FUSE (IGN FUSE) 

    OK: Go to next step 

  9. CHECK HARNESS AND CONNECTOR (ECM - INTEGRATION RELAY) 
    1. Remove the integration relay from the engine room relay block.
    2. Disconnect the integration relay connector.
    3. Disconnect the ECM connector.
    4. Measure the resistance according to the value(s) in the table below.

      Standard Resistance (Check for Open)

      Tester Connection Condition Specified Condition
      A37-28 (IGSW) - 1A-4 Always Below 1 Ω
    5. Reconnect the integration relay connector.
    6. Reinstall the integration relay.
    7. Reconnect the ECM connector.

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR (ECM - INTEGRATION RELAY) 

    OK: Go to next step 

  10. INSPECT FUSE (IG2 NO. 2 FUSE) 
    1. Remove the IG2 No. 2 fuse from the engine room relay block.
      Fig 5: Identifying IG2 NO. 2 Fuse
      GTY173650Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      IG2 No. 2 fuse Always Below 1 Ω
    3. Reinstall the fuse.

    NG → REPLACE FUSE (IG2 NO. 2 FUSE) 

    OK: Go to next step 

  11. CHECK HARNESS AND CONNECTOR (INTEGRATION RELAY - IGNITION SWITCH) 
    1. Remove the integration relay from the engine room relay block.
    2. Disconnect the integration relay connector.
    3. Disconnect the ignition switch connector.
    4. Measure the resistance according to the value(s) in the table below.

      Standard Resistance (Check for Open)

      Tester Connection Condition Specified Condition
      1A-2 - E5-6 (IG2) Always Below 1 Ω
    5. Reconnect the integration relay connector.
    6. Reinstall the integration relay.
    7. Reconnect the ignition switch connector.

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR (INTEGRATION RELAY - IGNITION SWITCH) 

    OK: Go to next step 

  12. INSPECT IGNITION SWITCH 
    1. Inspect the ignition switch. Refer to INSPECTION .

    NG → See step   15 

    OK → REPAIR OR REPLACE HARNESS OR CONNECTOR (IGNITION SWITCH - BATTERY) 

  13. REPLACE INTEGRATION RELAY. Refer to  REMOVAL. 
  14. REPLACE ECM. Refer to  REMOVAL 
  15. REPLACE IGNITION SWITCH. Refer to  REMOVAL 
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