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 coil of the No. 1 integration relay (EFI MAIN relay), closing the contacts and supplying power to terminals +B of the ECM.

WIRING DIAGRAM

A003EABE01

INSPECTION PROCEDURE

Note

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

PROCEDURE


  1. CHECK NO. 1 INTEGRATION RELAY (POWER SOURCE)

    A003BIME09
    Text in Illustration
    *a

    Front view of wire harness connector

    (to No. 1 Integration Relay)

    1. Remove the No. 1 integration relay from the No. 1 engine room relay block and junction block.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      10C-1 - Body ground Always 11 to 14 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (NO. 1 INTEGRATION RELAY - BATTERY)

    OK

  2. INSPECT NO. 1 INTEGRATION RELAY (EFI MAIN)


    1. Inspect the No. 1 integration relay (EFI MAIN) Click here.


    NG

    REPLACE NO. 1 INTEGRATION RELAY

    OK

  3. CHECK HARNESS AND CONNECTOR (NO. 1 INTEGRATION RELAY - ECM, BODY GROUND)


    1. Remove the No. 1 integration relay from the No. 1 engine room relay block and junction block.

    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
      B74-5 (MREL) - 10B-2 Always Below 1 Ω
      B74-1 (+B) - 10B-4 Always Below 1 Ω
      10B-3 - Body ground Always Below 1 Ω
      B74-5 (MREL) or 10B-2 - Body ground Always 10 kΩ or higher
      B74-1 (+B) or 10B-4 - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  4. 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
      D100-109 (E1) - Body ground Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  5. INSPECT ECM (IGSW VOLTAGE)

    A003HG9E18
    Text in Illustration
    *a

    Front view of wire harness connector

    (to ECM)

    1. Disconnect the ECM connectors.

    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
      B74-25 (IGSW) - Body ground Ignition switch ON 11 to 14 V

    NG

    CHECK NO. 2 INTEGRATION RELAY (POWER SOURCE) Click here

    OK

    REPLACE ECM Click here

  6. CHECK NO. 2 INTEGRATION RELAY (POWER SOURCE)

    A003GEWE02
    Text in Illustration
    *a

    Front view of wire harness connector

    (to No. 2 Integration Relay)

    1. Remove the No. 2 integration relay from the instrument panel relay block.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      12A-1 - Body ground Always 11 to 14 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  7. INSPECT NO. 2 INTEGRATION RELAY (IG2)


    1. Inspect the No. 2 integration relay (IG2) Click here.


    NG

    REPLACE NO. 2 INTEGRATION RELAY

    OK

  8. CHECK HARNESS AND CONNECTOR (NO. 2 INTEGRATION RELAY - IGNITION SWITCH, ECM, BODY GROUND)


    1. Disconnect the ECM connector.

    2. Disconnect the ignition switch connector.

    3. Remove the No. 2 integration relay from the instrument panel relay block.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      12D-2 - H25-6 (IG2) Always Below 1 Ω
      12B-7 - B74-25 (IGSW) Always Below 1 Ω
      12E-4 - Body ground Always Below 1 Ω
      12D-2 or H25-6 (IG2) - Body ground Always 10 kΩ or higher
      12B-7 or B74-25 (IGSW) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  9. INSPECT IGNITION SWITCH


    1. Inspect the ignition switch Click here.


    NG

    REPLACE IGNITION SWITCH

    OK

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