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Home >> Toyota >> 2020 >> Highlander L, FWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 45 (Engine Control System (T24A-FTS) - Diagnostic Codes (11 Of 11) & Circuit Tests (1 Of 2)) >> SFI System >> ECM Power Source Circuit [10/2022 - 11/2023] >> Procedure

ECM Power Source Circuit [10/2022 - 11/2023]: Procedure

WARNING: This page is about a different car, the 2025 Toyota Highlander, 2024 Toyota Highlander, and 2023 Toyota Highlander. However, it is still accessible from the selected car via links, so may be relevant.
  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
      A83-9 (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.
    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
      A83-8 (IGSW) - Body ground Ignition switch ON 11 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  6

    Result: 

    OK 

    See step  3

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

      Refer to PROCEDURE - Step 3

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE EFI-MAIN NO. 1 RELAY 

    Result: 

    OK 

    See step  4

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

      HINT: 

      Remove the IGT/INJ, EFI-MAIN NO. 2 and EFI-MAIN NO. 3 relays connected between the checked terminals as the coil inside the relay influences the measurement value.

    3. 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) - A83-2 (MREL) Always Below 1 Ω
      5 (EFI-MAIN NO. 1 relay) - C89-12 (+B) Always Below 1 Ω
      5 (EFI-MAIN NO. 1 relay) - C89-11 (+B2) Always Below 1 Ω
      5 (EFI-MAIN NO. 1 relay) - C89-10 (+B3) Always Below 1 Ω
      5 (EFI-MAIN NO. 1 relay) - C89-9 (+B4) Always Below 1 Ω
      2 (EFI-MAIN NO. 1 relay) or A83-2 (MREL) - Body ground and other terminals Always 10 kΩ or higher
      5 (EFI-MAIN NO. 1 relay), C89-12 (+B), C89-11 (+B2), C89-10 (+B3) or C89-9 (+B4) - 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 NO. 1 RELAY) 
    1. Remove the EFI-MAIN 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 (EFI-MAIN NO. 1 relay) - Body ground Always 11 to 14 V
      1 (EFI-MAIN NO. 1 relay) - Body ground Always 11 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to  PROBLEM SYMPTOMS TABLE [10/2022 - ] 

    Result: 

    NG 

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

  6. INSPECT IG2 NO. 1 RELAY 
    1. Inspect the IG2 NO. 1 relay.

      Refer to PROCEDURE - Step 6

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE IG2 NO. 1 RELAY 

    Result: 

    OK 

    See step  7

  7. CHECK HARNESS AND CONNECTOR (IG2 NO. 1 RELAY - ECM) 
    1. Disconnect the ECM connector.
    2. Remove the IG2 NO. 1 relay from the No. 1 engine room relay block and No. 1 junction block assembly.
    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) - A83-8 (IGSW) Always Below 1 Ω
      5 (IG2 NO. 1 relay) or A83-8 (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  8

  8. CHECK TERMINAL VOLTAGE (POWER SOURCE OF 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  9

  9. 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  10

  10. 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. 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 

    GO TO SMART KEY SYSTEM. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [10/2021 - 11/2023] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

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