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Home >> Lexus >> 2024 >> LX 600 Base >> Repair and Diagnosis (Single Page) >> Engine Performance >> System >> Engine Control System (W/O Canister Pump Module) - Diagnostic Codes (5 Of 5) & Circuit Tests (1 Of 2) >> SFI SYSTEM (w/o Canister Pump Module) >> ECM Power Source Circuit [12/2021 - ] >> Procedure
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ECM Power Source Circuit [12/2021 - ]: 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
      B70-9 (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 (IGP 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
      B70-8 (IGP) - 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 

    Refer to ON-VEHICLE INSPECTION [12/2021 - ]

    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, EFI MAIN NO. 2 relay, IGT/INJ relay, A/F relay and EFI MAIN NO. 3 relay from the No. 2 engine room relay block and junction block assembly.

      HINT: 

      Remove the EFI MAIN NO. 2 relay, IGT/INJ relay, A/F relay and EFI MAIN NO. 3 relay 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) - B70-3 (MREL) Always Below 1 Ω
      5 (EFI MAIN NO. 1 relay) - C38-12 (+B) Always Below 1 Ω
      5 (EFI MAIN NO. 1 relay) - C38-11 (+B2) Always Below 1 Ω
      5 (EFI MAIN NO. 1 relay) - C38-10 (+B3) Always Below 1 Ω
      2 (EFI MAIN NO. 1 relay) or B70-3 (MREL) - Body ground and other terminals Always 10 kΩ or higher
      5 (EFI MAIN NO. 1 relay), C38-12 (+B), C38-11 (+B2) or C38-10 (+B3) - 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. 2 engine room relay block and junction block assembly.
      GTY1074745Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 No. 2 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
      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 

    REPLACE ECM. Refer to  REMOVAL [12/2021 - ] 

    Result: 

    NG 

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

  6. INSPECT IGP NO. 2 RELAY 

    Refer to ON-VEHICLE INSPECTION [12/2021 - ]

    Result

    Proceed to
    OK
    NG

    Result: 

    NG 

    REPLACE IGP NO. 2 RELAY 

    Result: 

    OK 

    See step  7

  7. CHECK HARNESS AND CONNECTOR (IGP NO. 2 RELAY - ECM) 
    1. Disconnect the ECM connector.
    2. Remove the IGP NO. 2 relay from the No. 2 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
      5 (IGP NO. 2 relay) - B70-8 (IGP) Always Below 1 Ω
      5 (IGP NO. 2 relay) or B70-8 (IGP) - 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 IGP NO. 2 RELAY) 
    1. Remove the IGP NO. 2 relay from the No. 2 engine room relay block and junction block assembly.
      GTY1074810Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 No. 2 Engine Room Relay Block and Junction Block Assembly
      *2 IGP NO. 2 Relay
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      3 (IGP NO. 2 relay) - Body ground Always 11 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR (BATTERY - IGP NO. 2 RELAY) 

    Result: 

    OK 

    See step  9

  9. CHECK HARNESS AND CONNECTOR (IGP NO. 2 RELAY - BODY GROUND) 
    1. Remove the IGP NO. 2 relay from the No. 2 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 (IGP NO. 2 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 (IGP NO. 1 RELAY - IGP NO. 2 RELAY) 
    1. Remove the IGP NO. 1 relay from the No. 1 engine room relay block and junction block assembly.
    2. Remove the IGP NO. 2 relay from the No. 2 engine room relay block and junction block assembly.
    3. Remove the IGP NO. 3 relay from the No. 1 luggage room relay block and junction block assembly.

      HINT: 

      Remove the IGP NO. 3 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
      5 (IGP NO. 1 relay) - 1 (IGP NO. 2 relay) Always Below 1 Ω
      5 (IGP NO. 1 relay) or 1 (IGP NO. 2 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  11

  11. INSPECT IGP NO. 1 RELAY 

    Refer to ON-VEHICLE INSPECTION [12/2021 - ]

    Result

    Proceed to
    OK
    NG

    Result: 

    NG 

    REPLACE IGP NO. 1 RELAY 

    Result: 

    OK 

    See step  12

  12. CHECK TERMINAL VOLTAGE (POWER SOURCE OF IGP NO. 1 RELAY) 
    1. Remove the IGP NO. 1 relay from the No. 1 engine room relay block and junction block assembly.
      GTY1074734Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 No. 1 Engine Room Relay Block and Junction Block Assembly
      *2 IGP NO. 1 Relay
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

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

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

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

    Result: 

    OK 

    See step  13

  13. CHECK HARNESS AND CONNECTOR (IGP NO. 1 RELAY - BODY GROUND) 
    1. Remove the IGP 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 (IGP 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  14

  14. CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU - IGP NO. 1 RELAY) 
    1. Remove the IGP NO. 1 relay from the No. 1 engine room relay block and junction block assembly.
    2. Disconnect the certification ECU (smart key ECU assembly) connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      I40-24 (IGPD) - 1 (IGP NO. 1 relay) Always Below 1 Ω
      I40-24 (IGPD) or 1 (IGP NO. 1 relay) - 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 [12/2021 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

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