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Home >> Toyota >> 2020 >> Corolla L >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 102 (Engine Control System (M20A-FKS) - Circuit Tests (4 Of 6)) >> SFI System >> ECM Power Source Circuit [09/2022 - 11/2022] >> Procedure

ECM Power Source Circuit [09/2022 - 11/2022]: Procedure

WARNING: This page is about a different variant/trim than selected.
  1. CHECK VEHICLE SPECIFICATION 
    1. Check the vehicle specification

      Result

      Result Proceed to
      for TMMMS Made A
      for TMC Made B

    Result: 

    B 

    See step  11

    Result: 

    A 

    See step  2

  2. CHECK HARNESS AND CONNECTOR (POWER SOURCE OF NO. 1 INTEGRATION RELAY) 
    1. Disconnect the No. 1 integration relay connector.
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      1A-10 - Body ground Always 11 to 14 V
      1B-3 - Body ground Always 11 to 14 V
      1B-5 - Body ground Always 11 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

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

    Result: 

    OK 

    See step  3

  3. INSPECT NO. 1 INTEGRATION RELAY (EFI-MAIN RELAY, IG2 NO. 1 RELAY) 
    1. Inspect the No. 1 integration relay (EFI-MAIN relay, IG2 NO. 1 relay).

      Refer to INSPECTION [09/2022 - 11/2022]

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE NO. 1 INTEGRATION RELAY 

    Result: 

    OK 

    See step  4

  4. CHECK HARNESS AND CONNECTOR (NO. 1 INTEGRATION RELAY - ECM) 
    1. Disconnect the No. 1 integration relay connector.
    2. Disconnect the ECM connector.
    3. Remove the EFI-MAIN NO. 2 relay and EFI-MAIN NO. 3 relay from the No. 1 engine room relay block and No. 1 junction block assembly.

      HINT: 

      Remove the 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.

    4. Remove the VVT relay from No. 2 relay block assembly.

      HINT: 

      Remove the VVT relay connected between the checked terminals as the coil inside the relay influences the measurement value.

    5. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      1A-9 - A47-2 (IGSW) Always Below 1 Ω
      1B-6 - A47-15 (MREL) Always Below 1 Ω
      1B-4 - A47-9 (+B) Always Below 1 Ω
      1B-4 - A47-35 (+B2) Always Below 1 Ω
      1A-9 or A47-2 (IGSW) - Body ground and other terminals Always 10 kΩ or higher
      1B-6 or A47-15 (MREL) - Body ground and other terminals Always 10 kΩ or higher
      1B-4 or A47-9 (+B) - Body ground and other terminals Always 10 kΩ or higher
      1B-4 or A47-35 (+B2) - Body ground and other terminals Always 10 kΩ or higher

      HINT: 

      If a short is detected in any of the above circuits, there may be a malfunction in the circuit of a connected ECU.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  5

  5. 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
      A47-10 (E1) - Body ground Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  6

  6. CHECK HARNESS AND CONNECTOR (NO. 1 INTEGRATION RELAY - BODY GROUND) 
    1. Disconnect the No. 1 integration relay connector.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      1A-8 - Body ground Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  7

  7. CHECK TERMINAL VOLTAGE (IGSW TERMINAL VOLTAGE) 
    GTY850820Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    *a Front view of wire harness connector
    (to ECM)
    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
      A47-2 (IGSW) - Body ground Ignition switch ON 11 to 14 V

      Result

      Result Proceed to
      OK A
      NG (w/ Smart Key System) B
      NG (w/o Smart Key System) C

    Result: 

    A 

    PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE 

    Refer to PROBLEM SYMPTOMS TABLE [09/2022 - 11/2022]

    Result: 

    C 

    See step  9

    Result: 

    B 

    See step  8

  8. 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. Disconnect the No. 1 integration relay connector.
    3. Disconnect the instrument panel junction block assembly 4F 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
      I1-15 (IG1D) - 1A-7 Always Below 1 Ω
      I1-15 (IG1D) or 1A-7 - 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 [09/2022 - 11/2022]

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  9. INSPECT IGNITION OR STARTER SWITCH ASSEMBLY 
    1. Inspect the ignition or starter switch assembly.

      Refer to INSPECTION [01/2019 - ]

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE IGNITION OR STARTER SWITCH ASSEMBLY 

    Refer to REMOVAL [01/2019 - ]

    Result: 

    OK 

    See step  10

  10. CHECK HARNESS AND CONNECTOR (IGNITION OR STARTER SWITCH ASSEMBLY - NO. 1 INTEGRATION RELAY) 
    1. Disconnect the ignition or starter switch assembly connector.
    2. Disconnect the No. 1 integration relay connector.
    3. Disconnect the instrument panel junction block assembly 4F 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
      I12-8 (IG1) - 1A-7 Always Below 1 Ω
      I12-8 (IG1) or 1A-7 - Body ground and other terminals Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPAIR OR REPLACE HARNESS OR CONNECTOR (BATTERY - IGNITION OR STARTER SWITCH ASSEMBLY) 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  11. 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
      A47-10 (E1) - Body ground Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  12

  12. 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
      A47-2 (IGP) - Body ground Ignition switch ON 11 to 14 V
      GTY1107470Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to ECM)

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  16

    Result: 

    OK 

    See step  13

  13. INSPECT EFI-MAIN NO. 1 RELAY 

    Refer to ON-VEHICLE INSPECTION [09/2022 - 11/2022]

    Result

    Proceed to
    OK
    NG

    Result: 

    NG 

    REPLACE EFI-MAIN NO. 1 RELAY 

    Result: 

    OK 

    See step  14

  14. 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. 3 relay and EDU relay from the No. 1 engine room relay block and No. 1 junction block assembly.

      HINT: 

      Remove the EFI-MAIN NO. 2 VVT, 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
      1 (EFI-MAIN NO. 1 relay) - A47-15 (MREL) Always Below 1 Ω
      3 (EFI-MAIN NO. 1 relay) - A47-9 (+B) Always Below 1 Ω
      3 (EFI-MAIN NO. 1 relay) - A47-35 (+B2) Always Below 1 Ω
      1 (EFI-MAIN NO. 1 relay) or A47-15 (MREL) - Body ground and other terminals Always 10 kΩ or higher
      1 (EFI-MAIN NO. 1 relay), A47-15 (MREL), A47-9 (+B) or A47-35 (+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  15

  15. CHECK TERMINAL VOLTAGE (POWER SOURCE OF EFI-MAIN NO. 1 RELAY) 
    GTY1104117Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    *1 No. 1 Engine Room Relay Block and No. 1 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 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
      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 [09/2022 - 11/2022]

    Result: 

    NG 

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

  16. INSPECT IGP-MAIN RELAY 

    Refer to ON-VEHICLE INSPECTION [09/2022 - 11/2022]

    Result

    Proceed to
    OK
    NG

    Result: 

    NG 

    REPLACE IGP-MAIN RELAY 

    Result: 

    OK 

    See step  17

  17. CHECK HARNESS AND CONNECTOR (IGP-MAIN RELAY - ECM) 
    1. Disconnect the ECM connector.
    2. Remove the IGP-MAIN 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
      3 (IGP-MAIN relay) - A47-2 (IGP) Always Below 1 Ω
      3 (IGP-MAIN relay) or A47-2 (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  18

  18. CHECK HARNESS AND CONNECTOR (POWER SOURCE VOLTAGE OF IGP-MAIN RELAY) 
    GTY1108347Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    *1 No. 1 Engine Room Relay Block and No. 1 Junction Block Assembly
    *2 IGP-MAIN Relay
    1. Remove the IGP-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
      5 (IGP-MAIN relay) - Body ground Always 11 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

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

    Result: 

    OK 

    See step  19

  19. CHECK HARNESS AND CONNECTOR (IGP RELAY - BODY GROUND) 
    1. Remove the IGP-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 (IGP-MAIN relay) - Body ground Always Below 1 Ω

      Result

      Result Proceed to
      OK (w/ Smart Key System) A
      OK (w/o Smart Key System) B
      NG C

    Result: 

    B 

    See step  21

    Result: 

    C 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    A 

    See step  20

  20. CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU - IGP-MAIN RELAY) 
    1. Disconnect the certification ECU (smart key ECU assembly) connector.
    2. Remove the IGP-MAIN 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
      O175-24 (IGPD) - 2 (IGP-MAIN relay) Always Below 1 Ω
      O175-24 (IGPD) or 2 (IGP-MAIN relay) - Body ground and other terminals Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    GO TO SMART KEY SYSTEM 

    for TMMMS Made: Refer to HOW TO PROCEED WITH TROUBLESHOOTING [09/2022 - 11/2022]

    for TMC Made: Refer to HOW TO PROCEED WITH TROUBLESHOOTING [09/2022 - 11/2022]

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  21. INSPECT IGNITION OR STARTER SWITCH ASSEMBLY 
    1. Inspect the ignition or starter switch assembly.

      Refer to INSPECTION [01/2019 - ]

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE IGNITION OR STARTER SWITCH ASSEMBLY 

    Refer to REMOVAL [01/2019 - ]

    Result: 

    OK 

    See step  22

  22. CHECK HARNESS AND CONNECTOR (IGNITION OR STARTER SWITCH ASSEMBLY - IGP-MAIN RELAY) 
    1. Disconnect the ignition or starter switch assembly connector.
    2. Remove the IGP-MAIN 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
      I12-8 (IG1) - 2 (IGP-MAIN relay) Always Below 1 Ω
      I12-8 (IG1) or 2 (IGP-MAIN relay) - Body ground and other terminals Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPAIR OR REPLACE HARNESS OR CONNECTOR (BATTERY - IGNITION OR STARTER SWITCH ASSEMBLY) 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

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