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Home >> Toyota >> 2021 >> Highlander LE, 4WD >> Repair and Diagnosis >> Engine Performance >> Testing & Diagnosis >> Engine Control System (2GR-FKS) - Diagnostic Codes (6 Of 6) & Circuit Tests (1 Of 2) >> SFI System >> ECM Power Source Circuit [12/2019 - 10/2022] >> Procedure

ECM Power Source Circuit [12/2019 - 10/2022]: 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
      C54-53 (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 TERMINAL VOLTAGE (IGSW TERMINAL VOLTAGE) 
    1. Disconnect the ECM connector.
      GTY874858Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to ECM)
    2. Turn the ignition switch to ON.
    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      A28-4 (IGSW) - Body ground Ignition switch ON 11 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  7

    Result: 

    OK 

    See step  3

  3. INSPECT EFI-MAIN RELAY 

    Refer to PROCEDURE - Step 1

    Result

    Proceed to
    OK
    NG

    Result: 

    NG 

    REPLACE EFI-MAIN RELAY 

    Result: 

    OK 

    See step  4

  4. CHECK HARNESS AND CONNECTOR (EFI-MAIN RELAY - ECM) 
    1. Remove the EFI-MAIN relay, FUEL PMP relay and A/F HTR relay from the No. 1 engine room relay block and No. 1 junction block assembly.

      HINT: 

      Remove the FUEL PMP and A/F HTR relays connected between the checked terminals as the coil inside the relay influences the measurement value.

    2. Disconnect the ECM connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      2 (EFI-MAIN relay) - A28-46 (MREL) Always Below 1 Ω
      5 (EFI-MAIN relay) - A28-2 (+B) Always Below 1 Ω
      5 (EFI-MAIN relay) - A28-3 (+B2) Always Below 1 Ω
      2 (EFI-MAIN relay) or A28-46 (MREL) - Body ground and other terminals Always 10 kΩ or higher
      5 (EFI-MAIN relay) or A28-2 (+B) - Body ground and other terminals Always 10 kΩ or higher
      5 (EFI-MAIN relay) or A28-3 (+B2) - 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 TERMINAL VOLTAGE (POWER SOURCE OF EFI-MAIN RELAY) 
    GTY901690Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    *1 No. 1 Engine Room Relay Block and No. 1 Junction Block Assembly
    *2 EFI-MAIN Relay
    1. Remove the EFI-MAIN relay from the No. 1 engine room relay block and No. 1 junction block assembly.
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      3 (EFI-MAIN relay) - Body ground Always 11 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR (BATTERY - EFI-MAIN RELAY) 

    Result: 

    OK 

    See step  6

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

      Standard Resistance

      Tester Connection Condition Specified Condition
      1 (EFI-MAIN 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 [12/2019 - 10/2022] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  7. INSPECT IG2 NO. 1 RELAY 

    Refer to PROCEDURE - Step 5

    Result

    Proceed to
    OK
    NG

    Result: 

    NG 

    REPLACE IG2 NO. 1 RELAY 

    Result: 

    OK 

    See step  8

  8. CHECK HARNESS AND CONNECTOR (IG2 NO. 1 RELAY - ECM) 
    1. Remove the IG2 NO. 1 relay from the No. 1 engine room relay block and No. 1 junction block assembly.
    2. Disconnect the ECM connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      5 (IG2 NO. 1 relay) - A28-4 (IGSW) Always Below 1 Ω
      5 (IG2 NO. 1 relay) or A28-4 (IGSW) - 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 TERMINAL VOLTAGE (POWER SOURCE OF IG2 NO. 1 RELAY) 
    GTY900189Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    *1 No. 1 Engine Room Relay Block and No. 1 Junction Block Assembly
    *2 IG2 NO. 1 Relay
    1. Remove the IG2 NO. 1 relay from the No. 1 engine room relay block and No. 1 junction block assembly.
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      3 (IG2 NO. 1 relay) - Body ground Always 11 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR (BATTERY - IG2 NO. 1 RELAY) 

    Result: 

    OK 

    See step  10

  10. CHECK HARNESS AND CONNECTOR (IG2 NO. 1 RELAY - BODY GROUND) 
    1. Remove the IG2 NO. 1 relay from the No. 1 engine room relay block and No. 1 junction block assembly.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      2 (IG2 NO. 1 relay) - 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 (SMART KEY ECU ASSEMBLY) - IG2 NO. 1 RELAY) 
    1. Disconnect the certification ECU (smart key ECU assembly) connector.
    2. Remove the IG2 NO. 1 relay from the No. 1 engine room relay block and No. 1 junction block assembly.
    3. Disconnect the instrument panel junction block assembly 4B connector.

      HINT: 

      Disconnect the IG1-NO. 1, IG1-NO. 2 and IG2-NO. 2 relays 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
      H48-17 (IG1D) - 1 (IG2 NO. 1 relay) Always Below 1 Ω
      H48-17 (IG1D) or 1 (IG2 NO. 1 relay) - Body ground and other terminals Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    CHECK SMART KEY SYSTEM. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [12/2019 - 10/2021]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [10/2021 - 11/2023] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

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