СИСТЕМА ECD (для моделей с контроллером свечей накаливания) ECM Power Source Circuit

DESCRIPTION

When the ignition switch is turned to ON, battery voltage is applied to the IGSW terminal of the ECM. The output signal from the MREL terminal of the ECM causes a current to flow to the EFI-MAIN relay coil, closing the EFI-MAIN relay contacts and supplying power to terminals +B, +B2 and +B3 of the ECM.

WIRING DIAGRAM

B0042LAE01

CAUTION / NOTICE / HINT

Note

Inspect the fuses for circuits related to this system before performing the following procedure.

PROCEDURE


  1. CHECK TERMINAL VOLTAGE (POWER SOURCE OF IG2 RELAY)


    1. B0042GQC01
      *1 Engine Room Relay Block and Junction Block Assembly
      *2 IG2 Relay

      Remove the IG2 relay from the 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
      IG2 relay terminal 3 - Body ground Always 11 to 14 V
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (BATTERY - IG2 RELAY)

    OK

  2. CHECK TERMINAL VOLTAGE (POWER SOURCE OF EFI-MAIN RELAY)


    1. B0041P8C01
      *1 Engine Room Relay Block and Junction Block Assembly
      *2 EFI-MAIN Relay

      Remove the EFI-MAIN relay from the 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
      EFI-MAIN relay terminal 5 - Body ground Always 11 to 14 V
      Result
      Proceed to
      OK
      NG

    NG

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

    OK

  3. CHECK TERMINAL VOLTAGE (POWER SOURCE OF EFI-MAIN NO. 2 RELAY)


    1. B0043KJC01
      *1 Engine Room Relay Block and Junction Block Assembly
      *2 EFI-MAIN NO. 2 Relay

      for sedan.


      1. Remove the EFI-MAIN No. 2 relay from the 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
        EFI-MAIN No. 2 relay terminal 5 - Body ground Always 11 to 14 V
    2. B0044DQC01
      *1 Engine Room Relay Block and Junction Block Assembly
      *2 EFI-MAIN NO. 2 Relay

      for hatchback, wagon.


      1. Remove the EFI-MAIN No. 2 relay from the 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
        EFI-MAIN No. 2 relay terminal 5 - Body ground Always 11 to 14 V
      Result
      Proceed to
      OK
      NG

    NG

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

    OK

  4. INSPECT RELAY (IG2 RELAY)


    1. Inspect the IG2 relay.

      Click here

      Result
      Proceed to
      OK
      NG

    NG

    REPLACE RELAY (IG2 RELAY)

    OK

  5. INSPECT RELAY (EFI-MAIN RELAY)


    1. Inspect the EFI-MAIN relay.

      Click here

      Result
      Proceed to
      OK
      NG

    NG

    REPLACE RELAY (EFI-MAIN RELAY)

    OK

  6. INSPECT RELAY (EFI-MAIN NO.2 RELAY)


    1. B0042UC

      Remove the EFI-MAIN No. 2 relay from the 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
      3 - 5 Battery voltage not applied to terminals 1 and 2 10 kΩ or higher
      3 - 5 Battery voltage applied to terminals 1 and 2 Below 1 Ω
      Result
      Proceed to
      OK
      NG

    NG

    REPLACE RELAY (EFI-MAIN NO. 2 RELAY)

    OK

  7. CHECK HARNESS AND CONNECTOR (IG2 RELAY - BODY GROUND)


    1. Remove the IG2 relay from the 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
      IG2 relay terminal 2 - Body ground Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  8. CHECK HARNESS AND CONNECTOR (EFI-MAIN RELAY - BODY GROUND)


    1. Remove the EFI-MAIN relay from the 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
      EFI-MAIN relay terminal 2 - Body ground Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  9. CHECK HARNESS AND CONNECTOR (EFI-MAIN NO. 2 RELAY - BODY GROUND)


    1. Remove the EFI-MAIN No. 2 relay from the 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
      EFI-MAIN No. 2 relay terminal 2 - Body ground Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  10. CHECK HARNESS AND CONNECTOR (IG2 RELAY - ECM)


    1. Remove the IG2 relay from the 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
      IG2 relay terminal 5 - A169-37 (IGSW) Always Below 1 Ω
      IG2 relay terminal 5 or A169-37 (IGSW) - Body ground and other terminals Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  11. CHECK HARNESS AND CONNECTOR (EFI-MAIN RELAY - EFI-MAIN NO. 2 RELAY - ECM)


    1. Remove the EFI-MAIN relay from the engine room relay block and junction block assembly.

    2. Remove the EFI-MAIN No. 2 relay from the engine room relay block and junction block assembly.

    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
      EFI-MAIN relay terminal 3 - A169-2 (+B) Always Below 1 Ω
      EFI-MAIN relay terminal 3 - A169-14 (+B2) Always Below 1 Ω
      EFI-MAIN relay terminal 3 - A169-1 (+B3) Always Below 1 Ω
      EFI-MAIN relay terminal 1 - EFI-MAIN No. 2 relay terminal 1 - A169-9 (MREL) Always Below 1 Ω
      EFI-MAIN relay terminal 3 or A169-2 (+B) - Body ground and other terminals Always 10 kΩ or higher
      EFI-MAIN relay terminal 3 or A169-14 (+B2) - Body ground and other terminals Always 10 kΩ or higher
      EFI-MAIN relay terminal 3 or A169-1 (+B3) - Body ground and other terminals Always 10 kΩ or higher
      EFI-MAIN relay terminal 1, EFI-MAIN No. 2 relay terminal 1 or A169-9 (MREL) - Body ground and other terminals Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  12. 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
      A169-4 (E1) - Body ground Always Below 1 Ω
      Result
      Result Proceed to
      OK (w/ Entry and Start System) A
      OK (w/o Entry and Start System) B
      NG C

    B

    CHECK HARNESS AND CONNECTOR (IGNITION SWITCH ASSEMBLY - IG2 RELAY) Click here

    C

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    A

  13. CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU - IG2 RELAY)


    1. Disconnect the certification ECU (smart key ECU assembly) connector.

    2. Remove the IG2 relay from the 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
      E33-9 (IG2D) - IG2 relay terminal 1 Always Below 1 Ω
      E33-9 (IG2D) or IG2 relay terminal 1 - Body ground and other terminals Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    OK

    GO TO ENTRY AND START SYSTEM Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

  14. CHECK HARNESS AND CONNECTOR (IGNITION SWITCH ASSEMBLY - IG2 RELAY)


    1. Disconnect the ignition switch assembly connector.

    2. Remove the IG2 relay from the 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
      E4-3 (IG2) - IG2 relay terminal 1 Always Below 1 Ω
      E4-3 (IG2) or IG2 relay terminal 1 - Body ground and other terminals Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  15. INSPECT IGNITION SWITCH ASSEMBLY


    1. Inspect the ignition switch assembly.

      Click here

      Result
      Proceed to
      OK
      NG

    NG

    REPLACE IGNITION SWITCH ASSEMBLY Click here

    OK

  16. CHECK TERMINAL VOLTAGE (POWER SOURCE OF IGNITION SWITCH ASSEMBLY)


    1. B00428TC02
      *a

      Front view of wire harness connector

      (to Ignition Switch Assembly)

      Disconnect the ignition switch assembly connector.

    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage
      Tester Connection Condition Specified Condition
      E4-4 (AM2) - Body ground Always 11 to 14 V
      Result
      Proceed to
      OK
      NG

    OK

    PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE Click here

    NG

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