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ECM Power Source Circuit: Procedure

  1. INSPECT ECM (+B, +B1 VOLTAGE) 
    1. Turn the engine switch on (IG).
      Fig 1: Inspecting ECM (+B, +B1 Voltage)
      GTY277375Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      A5-6 (+B) - E4-7 (E1) Engine switch on (IG) 11 to 14 V
      A5-5 (+B1) - E4-7 (E1) Engine switch on (IG) 11 to 14 V
      TEXT IN ILLUSTRATION

      *1 Component with harness connected
      (ECM)

    NG → See step   2 

    OK → See step   11 

  2. CHECK HARNESS AND CONNECTOR (ECM - BODY GROUND) 
    1. Disconnect the ECM connector.
      Fig 2: Identifying (ECM - Body Ground) Connector
      GTY280614Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance (Check for Open)

      Tester Connection Condition Specified Condition
      E4-7 (E1) - Body ground Always Below 1 Ω
      TEXT IN ILLUSTRATION

      *1 Front view of wire harness connector
      (to ECM)
    3. Reconnect the ECM connector.

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

    OK: Go to next step 

  3. INSPECT ECM (IGSW VOLTAGE) 
    1. Turn the engine switch on (IG).
      Fig 3: Inspecting ECM (IGSW Voltage)
      GTY278035Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      A5-17 (IGSW) - E4-7 (E1) Engine switch on (IG) 11 to 14 V
      TEXT IN ILLUSTRATION

      *1 Component with harness connected
      (ECM)

    NG → See step   8 

    OK: Go to next step 

  4. INSPECT ECM (MREL VOLTAGE) 
    1. Turn the engine switch on (IG).
      Fig 4: Inspecting ECM (MREL Voltage)
      GTY277790Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      A5-13 (MREL) - E4-7 (E1) Engine switch on (IG) 11 to 14 V
      TEXT IN ILLUSTRATION

      *1 Component with harness connected
      (ECM)

    NG → See step   12 

    OK: Go to next step 

  5. INSPECT INTEGRATION NO. 1 RELAY (EFI MAIN RELAY) 
    1. Inspect the integration relay. Refer to INSPECTION .

    NG → See step   13 

    OK: Go to next step 

  6. CHECK HARNESS AND CONNECTOR (EFI MAIN RELAY - ECM AND BODY GROUND) 
    1. Check the harness and the connectors between the integration relay and the ECM.
      Fig 5: Identifying (EFI Main Relay - ECM And Body Ground) Connector
      GTY273394Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      1. Remove the integration relay from the engine room No. 2 relay 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 Condition Specified Condition
        2A-6 - A5-13 (MREL) Always Below 1 Ω

        Standard Resistance (Check for Short)

        Tester Connection Condition Specified Condition
        2A-6 or A5-13 (MREL) - Body ground Always 10 kΩ or higher
      4. Reconnect the ECM connector.
    2. Check the harness and the 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)

        Tester Connection Condition Specified condition
        2A-7 - Body ground Always Below 1 Ω
        TEXT IN ILLUSTRATION

        *1 Engine Room Relay Block No. 2 *2 Front view of wire harness connector
        (to Integration Relay)
        *3 Integration Relay *4 Front view of wire harness connector
        (to ECM)
      2. Reinstall the integration relay.

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

    OK: Go to next step 

  7. CHECK HARNESS AND CONNECTOR (EFI MAIN RELAY - ECM) 
    1. Remove the integration relay from the engine room No. 2 relay block.
      Fig 6: Identifying Integration Relay & Ngine Room No. 2 Relay Block
      GTY272769Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    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 Condition Specified Condition
      2A-8 - A5-6 (+B) Always Below 1 Ω
      2A-8 - A5-5 (+B1) Always Below 1 Ω

      Standard Resistance (Check for Short)

      Tester Connection Condition Specified Condition
      2A-8 or A5-6 (+B) - Body ground Always 10 kΩ or higher
      2A-8 or A5-5 (+B1) - Body ground Always 10 kΩ or higher
      TEXT IN ILLUSTRATION

      *1 Engine Room Relay Block No. 2 *2 Front view of wire harness connector
      (to Integration Relay)
      *3 Integration Relay *4 Front view of wire harness connector
      (to ECM)
    4. Reinstall the integration relay.
    5. Reconnect the ECM connector.

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

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

  8. INSPECT RELAY (IG2 RELAY) 
    1. Remove the IG2 relay from the engine room relay block No. 2.
      Fig 7: Inspecting A/F Relay
      GTY100984Courtesy 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
      3 - 5 No battery voltage applied across terminals 1 and 2 10 kΩ or higher
      3 - 5 Battery voltage applied across terminals 1 and 2 Below 1 Ω
    3. Reinstall the IG2 relay.

    NG → REPLACE RELAY (IG2 RELAY) 

    OK: Go to next step 

  9. CHECK HARNESS AND CONNECTOR (ECM - IG2 RELAY) 
    1. Remove the IG2 relay from the engine room relay block No. 2.
      Fig 8: Identifying IG2 Relay & Engine Room Relay Block No. 2
      GTY264302Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    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 Condition Specified Condition
      IG2 relay terminal 3 - A5-17 (IGSW) Always Below 1 Ω

      Standard Resistance (Check for Short)

      Tester Connection Condition Specified Condition
      IG2 relay terminal 3 or A5-17 (IGSW) - Body ground Always 10 kΩ or higher
      TEXT IN ILLUSTRATION

      *1 Front view of wire harness connector
      (to ECM)      		 *2 Engine Room No. 2 Relay Block
    4. Reinstall the IG2 relay.
    5. Reconnect the ECM connector.

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR (ECM - IG2 RELAY) 

    OK: Go to next step 

  10. CHECK HARNESS AND CONNECTOR (IG2 RELAY POWER SOURCE CIRCUIT) 
    1. Remove the IG2 relay from the engine room relay block No. 2.
      Fig 9: Check Harness And Connector (IG2 Relay Power Source Circuit)
      GTY271076Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      IG2 relay terminal 5 - Body ground Always 11 to 14 V
      TEXT IN ILLUSTRATION

      *1 Engine Room No. 2 Relay Block
    3. Reinstall the IG2 relay.

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR (IG2 RELAY - BATTERY) 

    OK → See step   14 

  11. PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to  PROBLEM SYMPTOMS TABLE 
  12. REPLACE ECM. Refer to  REMOVAL 
  13. REPLACE INTEGRATION NO. 1 RELAY. Refer to  REMOVAL 
  14. GO TO  SMART ACCESS SYSTEM WITH PUSH-BUTTON START (FOR START FUNCTION)  Refer to  HOW TO PROCEED WITH TROUBLESHOOTING 
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