ECD SYSTEM ECM Power Source Circuit

DESCRIPTION

When the ignition switch is turned to ON, the 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 NO. 1 relay coil, closing the EFI MAIN NO. 1 relay contacts and supplying power to terminal +B, +B2 and +B3 of the ECM.

WIRING DIAGRAM

A01QSWPE03

CAUTION / NOTICE / HINT

Note


  • When replacing the ECM, the ECM needs registration and initialization.

    Click here

  • Inspection the fuses for circuits related to this system before performing the following inspection procedure.

Tech Tips

When the ECM must be replaced, before replacing the ECM, perform the "Learning Values Save" function using the GTS. Then after installing the new ECM, perform all of the initialization/registrations for the "Learning Values Write" function by following the instructions shown on the tester display.

PROCEDURE


  1. CHECK HARNESS AND CONNECTOR (POWER SOURCE)


    1. A01QTMKC02
      *1 Engine Room Relay Block and Junction Block
      *2 EFI MAIN NO. 1 Relay
      *3 IG2 Relay

      Remove the IG2 relay from the engine room relay block and junction block.

    2. Remove the EFI MAIN NO. 1 relay from the engine room relay block and junction block.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      3 (IG2 relay holder) - Body ground Always 11 to 14 V
      5 (EFI MAIN NO. 1 relay holder) - Body ground Always 11 to 14 V

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      2 (IG2 relay holder) - Body ground Always Below 1 Ω
      2 (EFI MAIN NO. 1 relay holder) - Body ground Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (ENGINE ROOM NO. 1 RELAY BLOCK - BATTERY)

    OK

  2. INSPECT IG2 RELAY


    1. Inspect the IG2 relay.

      Click here

      Result
      Proceed to
      OK
      NG

    NG

    REPLACE IG2 RELAY

    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 (ENGINE ROOM RELAY BLOCK AND JUNCTION BLOCK - ECM)


    1. Disconnect the ECM connector.

    2. Remove the EFI MAIN NO. 1 relay from the engine room relay block and junction block.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A62-9 (MREL) - 1 (EFI MAIN NO. 1 relay holder) Always Below 1 Ω
      A62-2 (+B) - 3 (EFI MAIN NO. 1 relay holder) Always Below 1 Ω
      A62-14 (+B2) - 3 (EFI MAIN NO. 1 relay holder) Always Below 1 Ω
      A62-1 (+B3) - 3 (EFI MAIN NO. 1 relay holder) Always Below 1 Ω
      A62-9 (MREL) or 1 (EFI MAIN NO. 1 relay holder) - Body ground Always 10 kΩ or higher
      A62-2 (+B) or 3 (EFI MAIN NO. 1 relay holder) - Body ground Always 10 kΩ or higher
      A62-14 (+B2) or 3 (EFI MAIN NO. 1 relay holder) - Body ground Always 10 kΩ or higher
      A62-1 (+B3) or 3 (EFI MAIN NO. 1 relay holder) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  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
      A62-4 (E1) - Body ground Always Below 1 Ω
      A62-5 (E2) - Body ground Always Below 1 Ω
      A62-17 (E3) - Body ground Always Below 1 Ω
      A62-18 (E4) - Body ground Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  6. CHECK HARNESS AND CONNECTOR (IGSW TERMINAL VOLTAGE)

    A01QUFBC08
    *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 Switch Condition Specified Condition
      A62-37 (IGSW) - Body ground Ignition switch ON 11 to 14 V
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE ECM Click here

    NG

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


    1. Disconnect the ECM connector.

    2. Remove the IG2 relay from the engine room No. 1 relay block.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A62-37 (IGSW) - 5 (IG2 relay holder) Always Below 1 Ω
      A62-37 (IGSW) or 5 (IG2 relay holder) - Body ground Always 10 kΩ or higher
      Result
      Result Proceed to
      NG A
      OK (w/ Entry and Start System) B
      OK (w/o Entry and Start System) C

    A

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    C

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

    B

  8. 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.

    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 holder) Always Below 1 Ω
      G82-9 (IG2D) or 1 (IG2 relay holder) - 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

  9. 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.

    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 holder) Always Below 1 Ω
      G4-3 (IG2) or 1 (IG2 relay holder) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  10. INSPECT IGNITION SWITCH ASSEMBLY


    1. Inspect the ignition switch assembly.

      Click here

      Result
      Proceed to
      OK
      NG

    OK

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

    NG

    REPLACE IGNITION SWITCH ASSEMBLY Click here