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ECM Power Source Circuit [01/2017 - ]: Procedure

  1. 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

      Tester Connection Condition Specified Condition
      G1-53 (E1) - Body ground Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  2

  2. CHECK HARNESS AND CONNECTOR (IGSW TERMINAL VOLTAGE) 
    1. Disconnect the ECM connector.
      GTY815458Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to ECM)
    2. Turn the power switch on (IG).
    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      A58-4 (IGSW) - Body ground Power switch on (IG) 11 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  7

    Result: 

    OK 

    See step  3

  3. INSPECT EFI-MAIN NO. 1 RELAY 
    1. Inspect the EFI-MAIN NO. 1 relay.

      Refer to PROCEDURE - Step 1

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE EFI-MAIN NO. 1 RELAY 

    Result: 

    OK 

    See step  4

  4. CHECK HARNESS AND CONNECTOR (ECM - EFI-MAIN NO. 1 RELAY) 
    1. Disconnect the ECM connector.
    2. Remove the EFI-MAIN NO. 1 relay and A/F HTR relay from the No. 1 engine room relay block and junction block assembly.
    3. Remove the EFI-MAIN NO. 2 relay from the No. 2 luggage room relay block and junction block assembly.

      HINT: 

      Remove the EFI-MAIN No. 2 relay and A/F HTR relay connected between the checked terminals as the coil inside the relay influences the measurement value.

    4. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A58-46 (MREL) - 1 (EFI-MAIN NO. 1 relay) Always Below 1 Ω
      A58-2 (+B) - 3 (EFI-MAIN NO. 1 relay) Always Below 1 Ω
      A58-3 (+B2) - 3 (EFI-MAIN NO. 1 relay) Always Below 1 Ω
      A58-46 (MREL) or 1 (EFI-MAIN NO. 1 relay) - Body ground and other terminals Always 10 kΩ or higher
      A58-2 (+B) or 3 (EFI-MAIN NO. 1 relay) - Body ground and other terminals Always 10 kΩ or higher
      A58-3 (+B2) or 3 (EFI-MAIN NO. 1 relay) - Body ground and other terminals Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  5

  5. CHECK HARNESS AND CONNECTOR (POWER SOURCE VOLTAGE OF EFI-MAIN NO. 1 RELAY) 
    1. Remove the EFI-MAIN NO. 1 relay from the No. 1 engine room relay block and junction block assembly.
      GTY787192Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 No. 1 Engine Room Relay Block and Junction Block Assembly
      *2 EFI-MAIN NO. 1 Relay
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      5 (EFI-MAIN NO. 1 relay) - Body ground Always 11 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  6

  6. CHECK HARNESS AND CONNECTOR (EFI-MAIN NO. 1 RELAY - BODY GROUND) 
    1. Remove the EFI-MAIN NO. 1 relay from the No. 1 engine room relay block and junction block assembly.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      2 (EFI-MAIN NO. 1 relay) - Body ground Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to  PROBLEM SYMPTOMS TABLE [01/2017 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  7. INSPECT DRIVER SIDE JUNCTION BLOCK ASSEMBLY (IG2 D RELAY) 
    1. Inspect the IG2 D relay.

      Refer to PROCEDURE - Step 7

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE DRIVER SIDE JUNCTION BLOCK ASSEMBLY (IG2-MAIN RELAY) 

    Result: 

    OK 

    See step  8

  8. CHECK HARNESS AND CONNECTOR (ECM - IG2 D RELAY) 
    1. Disconnect the ECM connector.
    2. Disconnect the driver side junction block assembly connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A58-4 (IGSW) - 3C-1 Always Below 1 Ω
      A58-4 (IGSW) or 3C-1 - Body ground and other terminals Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  9

  9. CHECK HARNESS AND CONNECTOR (POWER SOURCE VOLTAGE OF IG2 D RELAY) 
    1. Disconnect the driver side junction block assembly connector.
      GTY803565Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Driver Side Junction Block Assembly)
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      3E-1 - Body ground Always 11 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  10

  10. CHECK HARNESS AND CONNECTOR (IG2 D RELAY - BODY GROUND) 
    1. Disconnect the driver side junction block assembly connector.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      3B-6 - Body ground Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  11

  11. CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU - IG2 D RELAY) 
    1. Disconnect the certification ECU (smart key ECU assembly) connector.
    2. Disconnect the driver side junction block assembly connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      P66-17 (IG1D) - 3B-18 Always Below 1 Ω
      P66-17 (IG1D) or 3B-18 - Body ground and other terminals Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    GO TO SMART ACCESS SYSTEM WITH PUSH-BUTTON START (FOR START FUNCTION). Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [01/2017 - 09/2018]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [09/2018 - 05/2023]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [05/2023 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

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