ECD SYSTEM ECM Power Source Circuit

DESCRIPTION

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

WIRING DIAGRAM

A00OACUE03

INSPECTION PROCEDURE

Note

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

PROCEDURE


  1. CHECK ECM (+B VOLTAGE)

    A00O5ERE96
    Text in Illustration
    *a

    Component with harness connected

    (ECM)

    1. Turn the ignition switch to ON.

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      G61-12 (+B) - C101-14 (E1) Ignition switch ON 11 to 14 V

    NG

    CHECK HARNESS AND CONNECTOR (ECM - BODY GROUND) Click here

    OK

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

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

    A00O8X0E13
    Text in Illustration
    *a

    Rear view of wire harness connector

    (to ECM)

    1. Disconnect the ECM connector.

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

      Standard Resistance (Check for Open)
      Tester Connection Condition Specified Condition
      C101-14 (E1) - Body ground Always Below 1 Ω

    3. Reconnect the ECM connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  3. CHECK ECM (IGSW VOLTAGE)

    A00O5ERE97
    Text in Illustration
    *a

    Component with harness connected

    (ECM)

    1. Turn the ignition switch to ON.

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      G61-14 (IGSW) - C101-14 (E1) Ignition switch ON 11 to 14 V

    NG

    INSPECT IGNITION SWITCH ASSEMBLY Click here

    OK

  4. CHECK ECM (MREL VOLTAGE)

    A00O5ERE98
    Text in Illustration
    *a

    Component with harness connected

    (ECM)

    1. Turn the ignition switch to ON.

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      G61-3 (MREL) - C101-14 (E1) Ignition switch ON 11 to 14 V

    NG

    REPLACE ECM Click here

    OK

  5. CHECK NO. 1 INTEGRATION RELAY (EFI)

    A00O40WE21
    Text in Illustration
    *a

    Rear view of wire harness connector

    (to No. 1 Integration Relay)

    1. Turn the ignition switch to ON.

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

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

    3. Reconnect the No. 1 integration relay (EFI) connector.


    NG

    REPLACE NO. 1 INTEGRATION RELAY (EFI)

    OK

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


    1. Disconnect the No. 1 integration relay (EFI) connector from the engine room junction block.

    2. Disconnect the ECM connector.

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

      Standard Resistance (Check for Open)
      Tester Connection Condition Specified Condition
      1B-2 - G61-3 (MREL) Always Below 1 Ω
      1B-4 - G61-12 (+B) Always Below 1 Ω
      1B-3 - Body ground Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      1B-2 or G61-3 (MREL) - Body ground Always 10 kΩ or higher
      1B-4 or G61-12 (+B) - Body ground Always 10 kΩ or higher

    4. Reconnect the No. 1 integration relay (EFI) connector.

    5. Reconnect the ECM connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

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

  7. INSPECT IGNITION SWITCH ASSEMBLY


    1. Inspect the ignition switch assembly Click here.


    NG

    REPLACE IGNITION SWITCH ASSEMBLY Click here

    OK

    REPAIR OR REPLACE HARNESS OR CONNECTOR (BATTERY - IGNITION SWITCH, IGNITION SWITCH - ECM)