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 current to flow to the MAIN relay coil, closing the contacts of the EFI relay and supplying power to terminal +B of the ECM.

WIRING DIAGRAM

A01E1WFE01

INSPECTION PROCEDURE

PROCEDURE


  1. CHECK ECM (+B VOLTAGE)

    A01E2VTE51

    1. Turn the ignition switch ON.

    2. Measure the voltage of the ECM connector.

      Standard voltage
      Tester Connection Specified Condition
      E20-12 (+B) - E23-14 (E1) 9 to 14 V

    OK

    PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE

    NG

  2. CHECK WIRE HARNESS (ECM - BODY GROUND)

    A01DWNME07

    1. Disconnect the E23 ECM connector.

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

      Standard resistance
      Tester Connection Specified Condition
      E23-14 (E1) - Body ground Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS AND CONNECTOR

    OK

  3. CHECK ECM (IGSW VOLTAGE)

    A01E2VTE52

    1. Turn the ignition switch ON.

    2. Measure the voltage of the ECM connector.

      Standard voltage
      Tester Connection Specified Condition
      E20-14 (IGSW) - E23-14 (E1) 9 to 14 V

    OK

    CHECK ECM (MREL VOLTAGE) Click here

    NG

  4. INSPECT FUSE (IGN)

    A01E1DOE01

    1. Remove the IGN fuse from the instrument panel junction block.

    2. Measure the resistance of the IGN fuse.

      Standard resistance
      Tester Connection Specified Condition
      IGN fuse Below 1 Ω

    NG

    CHECK FOR SHORT IN ALL HARNESSES AND COMPONENTS CONNECTED TO FUSE

    OK

  5. INSPECT IGNITION SWITCH ASSEMBLY

    A01DX1EE02

    1. 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

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

  6. CHECK ECM (MREL VOLTAGE)

    A01E2VTE53

    1. Turn the ignition switch ON.

    2. Measure the voltage of the ECM connector.

      Standard voltage
      Tester Connection Specified Condition
      E20-3 (MREL) - E23-14 (E1) 9 to 14 V

    NG

    REPLACE ECM

    OK

  7. INSPECT FUSE (EFI)

    A01DX18E01

    1. Remove the EFI fuse from the engine room junction block.

    2. Measure the resistance of the EFI fuse.

      Standard resistance
      Tester Connection Specified Condition
      EFI fuse Below 1 Ω

    NG

    CHECK FOR SHORT IN ALL HARNESSES AND COMPONENTS CONNECTED TO FUSE

    OK

  8. CHECK INTEGRATION NO.1 RELAY (MAIN RELAY)

    A01E00JE03

    1. Disconnect the 1J integration relay connector from the engine room junction block Click here.

    2. Measure the voltage of the integration relay.

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

    NG

    REPLACE INTEGRATION NO.1 RELAY

    OK

  9. CHECK WIRE HARNESS (INTEGRATION RELAY [MAIN RELAY] - ECM AND BODY GROUND)

    A01DVUCE03

    1. Disconnect the 1J integration relay connector from the engine room junction block Click here.

    2. Disconnect the E20 ECM connector.

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

      Standard resistance
      Tester Connection Specified Condition
      1J-2 - E20-3 (MREL) Below 1 Ω
      1J-4 - E20-12 (+B) Below 1 Ω
      1J-3 - Body ground Below 1 Ω
      1J-2 or E20-3 (MREL) - Body ground 10 kΩ or higher
      1J-4 or E20-12 (+B) - Body ground 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS AND CONNECTOR

    OK

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