ECD SYSTEM ECM Power Source Circuit

DESCRIPTION

When the ignition switch is turned to ON, the battery voltage is applied to IGSW of the ECM. The output signal from the MREL terminal of the ECM causes a current to flow to the coil, closing the contacts of the EFI MAIN NO. 1 relay and supplying power to either terminal +B or +B2 of the ECM.

WIRING DIAGRAM

A01QOFOE01

CAUTION / NOTICE / HINT

Note


  • Inspect the fuses of circuits related to this system before performing the following inspection procedure.

  • After replacing the ECM, the new ECM needs registration (Click here ) and initialization Click here.

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
      B76-109 (E1) - Body ground Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  2. CHECK TERMINAL VOLTAGE (IGSW TERMINAL VOLTAGE)


    1. A01QO9FC06
      *a

      Front view of wire harness connector

      (to ECM)

      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
      A61-25(IGSW) - Body ground Ignition switch ON 11 to 14 V
      Result
      Proceed to
      OK
      NG

    NG

    INSPECT IG2 RELAY Click here

    OK

  3. INSPECT EFI-MAIN NO. 1 RELAY


    1. Inspect the EFI-MAIN NO. 1 relay.

      Click here

      Result
      Proceed to
      OK
      NG

    NG

    REPLACE EFI-MAIN NO. 1 RELAY

    OK

  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 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
      A61-45 (MREL) - 1 (EFI-MAIN NO. 1 relay) Always Below 1 Ω
      A61-1 (+B) - 3 (EFI-MAIN NO. 1 relay) Always Below 1 Ω
      A61-20 (+B2) - 3 (EFI-MAIN NO. 1 relay) Always Below 1 Ω
      A61-45 (MREL) or 1 (EFI-MAIN NO. 1 relay) - Body ground Always 10 kΩ or higher
      A61-1 (+B) or 3 (EFI-MAIN NO. 1 relay) - Body ground Always 10 kΩ or higher
      A61-20 (+B2) or 3 (EFI-MAIN NO. 1 relay) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  5. CHECK TERMINAL VOLTAGE (POWER SOURCE OF EFI-MAIN NO. 1 RELAY)


    1. A01QRU5C02
      *1 Engine Room Relay Block and Junction Block Assembly
      *2 EFI-MAIN NO. 1 relay

      Remove the EFI-MAIN NO. 1 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
      5 (EFI-MAIN NO. 1 relay) - Body ground Always 11 to 14 V
      Result
      Proceed to
      OK
      NG

    NG

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

    OK

  6. CHECK HARNESS AND CONNECTOR (EFI-MAIN NO. 1 RELAY - BODY GROUND)


    1. Remove the EFI-MAIN NO. 1 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
      2 (EFI-MAIN NO. 1 relay) - Body ground Always Below 1 Ω
      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

  7. INSPECT IG2 RELAY


    1. Inspect the IG2 relay.

      Click here

      Result
      Proceed to
      OK
      NG

    NG

    REPLACE IG2 RELAY

    OK

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


    1. Disconnect the ECM 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
      A61-25(IGSW) - 5 (IG2 relay) Always Below 1 Ω
      A61-25(IGSW) or 5 (IG2 relay) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

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


    1. A01QTH9C02
      *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. 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
      3 (IG2 relay) - Body ground Ignition switch ON 11 to 14 V
      Result
      Proceed to
      OK
      NG

    NG

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

    OK

  10. 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
      2 (IG2 relay) - 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

    INSPECT IGNITION OR STARTER SWITCH ASSEMBLY Click here

    C

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    A

  11. CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) - 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
      G82-9 (IG2D) - 1 (IG2 relay) Always Below 1 Ω
      G82-9 (IG2D) or 1 (IG2 relay) - Body ground 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

  12. INSPECT IGNITION OR STARTER SWITCH ASSEMBLY


    1. Inspect the ignition or starter switch assembly.

      Click here

      Result
      Proceed to
      OK
      NG

    NG

    REPLACE IGNITION OR STARTER SWITCH ASSEMBLY Click here

    OK

  13. CHECK HARNESS AND CONNECTOR (IGNITION OR STARTER SWITCH ASSEMBLY - IG2 RELAY)


    1. Disconnect the ignition or starter 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
      G4-3 (IG2) - 1 (IG2 relay) Always Below 1 Ω
      G4-3 (IG2) or 1 (IG2 relay) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    OK

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

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR