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Home >> Lexus >> 2020 >> UX 200 Luxury >> Repair and Diagnosis >> External Pages >> Different car >> Section 24 (Engine Control System (SFI) (M20A-FXS) - Diagnostic Codes (6 Of 6) & Circuit Tests (Hybrid)) >> SFI System >> ECM Power Source Circuit [10/2018 - ] >> Procedure

ECM Power Source Circuit [10/2018 - ]: Procedure

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  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
      A36-10 (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) 
    GTY806399Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    *a Front view of wire harness connector
    (to ECM)
    1. Disconnect the ECM connector.
    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
      A36-2 (IGSW) - Body ground Power switch on (IG) 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 ON-VEHICLE INSPECTION [10/2018 - ]

      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. Remove the EFI-MAIN NO. 1 relay from the No. 1 engine room relay block and junction block assembly.
    2. Remove the No. 1 integration relay, EFI-MAIN NO. 2 relay and EFI-MAIN NO. 3 relay from the No. 1 engine room relay block and junction block assembly.

      HINT: 

      Remove the No. 1 integration relay, EFI-MAIN NO. 2 relay and EFI-MAIN NO. 3 relay connected between the checked terminals as the coil inside the relay influences the measurement value.

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

      Standard Resistance

      Tester Connection Condition Specified Condition
      1 (EFI-MAIN NO. 1 relay) - A36-15 (MREL) Always Below 1 Ω
      3 (EFI-MAIN NO. 1 relay) - A36-9 (+B) Always Below 1 Ω
      3 (EFI-MAIN NO. 1 relay) - A36-35 (+B2) Always Below 1 Ω
      1 (EFI-MAIN NO. 1 relay) or A36-15 (MREL) - Body ground and other terminals Always 10 kΩ or higher
      3 (EFI-MAIN NO. 1 relay), A36-9 (+B) or A36-35 (+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 NO. 1 RELAY) 
    GTY824302Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    *1 No. 1 Engine Room Relay Block and Junction Block Assembly
    *2 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.
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

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

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE ECM. Refer to  REMOVAL [10/2018 - 07/2022]  Refer to  REMOVAL [07/2022 - ] 

    Result: 

    NG 

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

  6. INSPECT NO. 1 INTEGRATION RELAY (IG2 NO. 1 RELAY) 
    1. Inspect the No. 1 integration relay (IG2 NO. 1 relay).

      Refer to INSPECTION [10/2018 - ]

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE NO. 1 INTEGRATION RELAY 

    Result: 

    OK 

    See step  7

  7. CHECK HARNESS AND CONNECTOR (NO. 1 INTEGRATION RELAY - ECM) 
    1. Remove the No. 1 integration relay from the No. 1 engine room relay block and 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
      2A-9 - A36-2 (IGSW) Always Below 1 Ω
      2A-9 or A36-2 (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 NO. 1 INTEGRATION RELAY) 
    GTY832834Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    *a Front view of wire harness connector
    (to No. 1 Integration Relay)
    1. Remove the No. 1 integration relay from the No. 1 engine room relay block and junction block assembly.
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      2A-10 - Body ground Always 11 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

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

    Result: 

    OK 

    See step  9

  9. CHECK HARNESS AND CONNECTOR (NO. 1 INTEGRATION RELAY - BODY GROUND) 
    1. Remove the No. 1 integration 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
      2A-8 - 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) - NO. 1 INTEGRATION RELAY) 
    1. Disconnect the certification ECU (smart key ECU assembly) connector.
    2. Remove the No. 1 integration relay from the No. 1 engine room relay block and junction block assembly.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      F44-17 (IG1D) - 2A-7 Always Below 1 Ω
      F44-17 (IG1D) or 2A-7 - 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. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [10/2018 - 07/2022]  Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [07/2022 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

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