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Home >> Lexus >> 2019 >> NX 300 Base, AWD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - Circuit Tests & Symptom Tests (2 Of 2) >> SFI System >> ECM Power Source Circuit [10/2014 - ] >> Procedure
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ECM Power Source Circuit [10/2014 - ]: 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
      C20-53 (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.
      GTY516256Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to ECM)
    2. Turn the engine switch on (IG).
    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      A35-6 (IGSW) - Body ground Engine 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 ON-VEHICLE INSPECTION [10/2014 - ]

      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 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
      A35-46 (MREL) - 1 (EFI-MAIN NO. 1 relay) Always Below 1 Ω
      A35-2 (+B) - 3 (EFI-MAIN NO. 1 relay) Always Below 1 Ω
      A35-3 (+B2) - 3 (EFI-MAIN NO. 1 relay) Always Below 1 Ω
      A35-46 (MREL) or 1 (EFI-MAIN NO. 1 relay) - Body ground and other terminals Always 10 kΩ or higher
      A35-2 (+B) or 3 (EFI-MAIN NO. 1 relay) - Body ground and other terminals Always 10 kΩ or higher
      A35-3 (+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.
      GTY499846Courtesy 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 [10/2014 - 05/2018]  , or refer to  PROBLEM SYMPTOMS TABLE [05/2018 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  7. INSPECT IG2-MAIN RELAY 
    1. Inspect the IG2-MAIN relay.

      Refer to ON-VEHICLE INSPECTION [10/2014 - ]

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE IG2-MAIN RELAY 

    Result: 

    OK 

    See step  8

  8. CHECK HARNESS AND CONNECTOR (ECM - IG2-MAIN RELAY) 
    1. Disconnect the ECM connector.
    2. Remove the IG2-MAIN 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
      A35-6 (IGSW) - 5 (IG2-MAIN relay) Always Below 1 Ω
      A35-6 (IGSW) or 5 (IG2-MAIN 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  9

  9. CHECK HARNESS AND CONNECTOR (POWER SOURCE VOLTAGE OF IG2-MAIN RELAY) 
    1. Remove the IG2-MAIN relay from the No. 1 engine room relay block and junction block assembly.
      GTY514927Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 No. 1 Engine Room Relay Block and Junction Block Assembly
      *2 IG2-MAIN Relay
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      3 (IG2-MAIN 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  10

  10. CHECK HARNESS AND CONNECTOR (IG2-MAIN RELAY - BODY GROUND) 
    1. Remove the IG2-MAIN 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 (IG2-MAIN 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 - IG2-MAIN RELAY) 
    1. Remove the IG2-MAIN 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
      I51-3 (IG1D) - 1 (IG2-MAIN relay) Always Below 1 Ω
      I51-3 (IG1D) or 1 (IG2-MAIN 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. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [10/2014 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

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