ECD SYSTEM ECM Power Source Circuit

DTC Code DTC Name
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 relay coil, closing the EFI MAIN relay contacts and supplying power to terminal +B, +B2 and +B3 of the ECM.

WIRING DIAGRAM

A321033E04

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.

Tip:

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. A366315C01

      *1

      Engine Room Relay Block and Junction Block

      *2

      EFI MAIN Relay

      *a

      Front view of wire harness connector

      (to No. 1 Integration Relay)

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

    2. Remove the EFI MAIN 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

      1K-1 - Body ground

      Always

      11 to 14 V

      5 (EFI MAIN 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

      1I-2 - Body ground

      Always

      Below 1 Ω

      1 (EFI MAIN 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 NO. 1 INTEGRATION RELAY (IG2)

    1. Inspect the No. 1 integration relay (IG2 relay).

      Click here

    Result

    Proceed to

    OK

    NG
    NG

    REPLACE NO. 1 INTEGRATION RELAY

    Click here

    OK

  3. INSPECT EFI MAIN RELAY

    1. Inspect the EFI MAIN relay.

      Click hereClick here

    Result

    Proceed to

    OK

    NG
    NG

    REPLACE EFI MAIN 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 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

      A50-9 (MREL) - 2 (EFI MAIN relay holder)

      Always

      Below 1 Ω

      A50-2 (+B) - 3 (EFI MAIN relay holder)

      Always

      Below 1 Ω

      A50-14 (+B2) - 3 (EFI MAIN relay holder)

      Always

      Below 1 Ω

      A50-1 (+B3) - 3 (EFI MAIN relay holder)

      Always

      Below 1 Ω

      A50-9 (MREL) or 2 (EFI MAIN relay holder) - Body ground

      Always

      10 kΩ or higher

      A50-2 (+B) or 3 (EFI MAIN relay holder) - Body ground

      Always

      10 kΩ or higher

      A50-14 (+B2) or 3 (EFI MAIN relay holder) - Body ground

      Always

      10 kΩ or higher

      A50-1 (+B3) or 3 (EFI MAIN 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

      A50-4 (E1) - Body ground

      Always

      Below 1 Ω

      A50-5 (E2) - Body ground

      Always

      Below 1 Ω

      A50-17 (E3) - Body ground

      Always

      Below 1 Ω

      A50-18 (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)

    A355840C06

    *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

      A50-26 (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 - NO. 1 INTEGRATION RELAY)

    1. Disconnect the ECM connector.

    2. Remove the No. 1 integration 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

      A50-26 (IGSW) - 1I-4

      Always

      Below 1 Ω

      A50-26 (IGSW) or 1I-4 - 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 - NO. 1 INTEGRATION RELAY)Click here

    B

  8. CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) - NO. 1 INTEGRATION RELAY)

    1. Disconnect the certification ECU (smart key ECU assembly) connector.

    2. Remove the No. 1 integration 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

      E33-9 (IG2D) - 1I-3

      Always

      Below 1 Ω

      E33-9 (IG2D) or 1I-3 - Body ground

      Always

      10 kΩ or higher

    Result

    Proceed to

    OK

    NG
    OK

    GO TO ENTRY AND START SYSTEM

    Click hereClick here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

  9. CHECK HARNESS AND CONNECTOR (IGNITION SWITCH ASSEMBLY - NO. 1 INTEGRATION RELAY)

    1. Disconnect the ignition switch assembly connector.

    2. Remove the No. 1 integration 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

      E4-3 (IG2) - 1I-3

      Always

      Below 1 Ω

      E4-3 (IG2) or 1I-3 - 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