ECD SYSTEM ECM Power Source Circuit

DESCRIPTION

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

WIRING DIAGRAM

A01BFWZE01

INSPECTION PROCEDURE

Note

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

PROCEDURE


  1. INSPECT ECM TERMINAL VOLTAGE (+B TERMINAL)


    1. A01BDNSE41

      Turn the ignition switch ON.

    2. Measure the voltage of the ECM connectors.

      Standard voltage
      Tester Connection Specified Condition
      B9-1 (+B) - D3-7 (E1) 9 to 14 V

    OK

    PROCEED TO NEXT CIRCUIT INSPECTION SHOWN ON PROBLEM SYMPTOMS TABLE

    NG

  2. CHECK HARNESS AND CONNECTOR (ECM - BODY GROUND)


    1. A01BFM0E06

      Disconnect the D3 ECM connector.

    2. Measure the resistance of the wire harness side connector.

      Standard resistance
      Tester Connection Specified Condition
      D3-7 (E1) - Body ground Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS AND CONNECTOR

    OK

  3. CHECK ECM TERMINAL VOLTAGE (IGSW TERMINAL)


    1. A01BDNSE18

      Turn the ignition switch ON.

    2. Measure the voltage of the ECM connectors.

      Standard voltage
      Tester Connection Specified Condition
      B9-9 (IGSW) - D3-7 (E1) 9 to 14 V

    OK

    CHECK ECM TERMINAL VOLTAGE (MREL TERMINAL) Click here

    NG

  4. INSPECT FUSE (IGN FUSE)


    1. A01BG9BE01

      Remove the IGN fuse from the instrument panel J/B.

    2. Measure the resistance of the fuse.

      Standard resistance
      Below 1 Ω

    NG

    CHECK FOR SHORT IN ALL HARNESS AND COMPONENTS CONNECTED TO FUSE, AND REPLACE FUSE

    OK

  5. INSPECT IGNITION SWITCH ASSEMBLY


    1. A01BCGXE01

      Disconnect the ignition switch connector.

    2. Measure the resistance of the ignition switch.

      Standard resistance
      Tester Connection Switch Condition Specified Condition
      5 (AM2) - 6 (IG2) LOCK 10 kΩ or higher
      5 (AM2) - 6 (IG2) ON Below 1 Ω

    NG

    REPLACE IGNITION SWITCH ASSEMBLY

    OK

  6. CHECK ECM TERMINAL VOLTAGE (MREL TERMINAL)


    1. A01BDNSE20

      Turn the ignition switch ON.

    2. Measure the voltage of the ECM connectors.

      Standard voltage
      Tester Connection Specified Condition
      B9-8 (MREL) - D3-7 (E1) 9 to 14 V

    NG

    REPLACE ECM

    OK

  7. INSPECT FUSE (EFI FUSE)


    1. A01BI5DE02

      Remove the EFI fuse from the engine room J/B and K/B No.1.

    2. Measure the resistance of the fuse.

      Standard resistance
      Below 1 Ω

    NG

    CHECK FOR SHORT IN ALL HARNESS AND COMPONENTS CONNECTED TO FUSE, AND REPLACE FUSE

    OK

  8. INSPECT INTEGRATION RELAY (MAIN RELAY)


    1. A01BI6IE01

      Remove the integration relay from the engine room J/B and R/B No.1.

    2. Disconnect the 1J integration relay connector.

    3. Measure the voltage of the MAIN relay.

      Standard voltage
      Tester Connection Condition Specified Condition
      1J-4 - Body ground Ignition switch ON 10 to 14 V

    NG

    REPLACE ECM

    OK

  9. CHECK HARNESS AND CONNECTOR (MAIN RELAY - ECM)


    1. A01BD1QE01

      Disconnect the 1J integration relay connector from the engine room J/B and R/B No.1.

    2. Disconnect the B9 ECM connector.

    3. Measure the resistance of the wire harness side connectors.

      Standard resistance
      Tester Connection Specified Condition
      1J-4 - B9-1 (+B) Below 1 Ω
      1J-4 or B9-1 (+B) - Body ground 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS AND CONNECTOR (MAIN RELAY - ECM)

    OK

    REPAIR OR REPLACE HARNESS AND CONNECTOR (+B TERMINAL OF ECM - BATTERY POSITIVE TERMINAL)