SFI 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 IGSW of the ECM. The output signal from the MREL terminal of the ECM causes a current to flow to the coil, closing the contacts of the integration relay (EFI MAIN relay) and supplying power to either terminal +B or +B2 of the ECM.

WIRING DIAGRAM

A342932E02

CAUTION / NOTICE / HINT

Note:

  • After turning the ignition switch off, waiting time may be required before disconnecting the cable from the negative (-) battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) battery terminal notices before proceeding with work (Click here).

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

PROCEDURE

  1. 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 (Check for Open)

      Tester Connection

      Condition

      Specified Condition

      C111-59 (E1) - Body ground

      Always

      Below 1 Ω

    3. Reconnect the ECM connector.

    REPAIR OR REPLACE HARNESS OR CONNECTOR (ECM - BODY GROUND)

  2. INSPECT ECM (IGSW VOLTAGE)

    1. U123361E02

      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

      A76-6 (IGSW) - Body ground

      Ignition switch ON

      11 to 14 V
      Table 1. Text in Illustration

      *a

      Front view of wire harness connector

      (to ECM)

    4. Reconnect the ECM connector.

    INSPECT INTEGRATION RELAY (IG2 RELAY)Click here

  3. INSPECT INTEGRATION RELAY (EFI MAIN RELAY)

    1. Inspect the EFI MAIN relay (Click here).

    REPLACE INTEGRATION RELAY

  4. CHECK HARNESS AND CONNECTOR (INTEGRATION RELAY (EFI MAIN RELAY) - ECM)

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

    2. Disconnect the integration relay connector.

    3. Disconnect the ECM connector.

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

      Standard Resistance (Check for Open)

      Tester Connection

      Condition

      Specified Condition

      1B-4 - A76-2 (+B)

      Always

      Below 1 Ω

      1B-4 - A76-3 (+B2)

      Always

      Below 1 Ω

      Standard Resistance (Check for Short)

      Tester Connection

      Condition

      Specified Condition

      1B-4 or A76-2 (+B) - Body ground

      Always

      10 kΩ or higher

      1B-4 or A76-3 (+B2) - Body ground

      Always

      10 kΩ or higher

    5. Reconnect the ECM connector.

    6. Reconnect the integration relay connector.

    7. Reinstall the integration relay.

    REPAIR OR REPLACE HARNESS OR CONNECTOR (INTEGRATION RELAY (EFI MAIN RELAY) - ECM)

  5. CHECK HARNESS AND CONNECTOR (EFI MAIN RELAY - BATTERY)

    1. Disconnect the cable from the negative (-) battery terminal.

    2. Disconnect the cable from the positive (+) battery terminal.

    3. Remove the integration relay from the engine room No. 1 relay block.

    4. Disconnect the integration relay connector.

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

      Standard Resistance (Check for Open)

      Tester Connection

      Condition

      Specified Condition

      1C-1 - Battery positive terminal

      Always

      Below 1 Ω

      Standard Resistance (Check for Short)

      Tester Connection

      Condition

      Specified Condition

      1C-1 or Battery positive terminal - Body ground

      Always

      10 kΩ or higher

    6. Reconnect the integration relay connector.

    7. Reinstall the integration relay.

    8. Reconnect the cable to the positive (+) battery terminal.

    9. Reconnect the cable to the negative (-) battery terminal.

    REPAIR OR REPLACE HARNESS OR CONNECTOR (EFI MAIN RELAY - BATTERY)

  6. CHECK HARNESS AND CONNECTOR (INTEGRATION RELAY (EFI MAIN RELAY) - BODY GROUND)

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

    2. Disconnect the integration relay 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-3 - Body ground

      Always

      Below 1 Ω

    4. Reconnect the integration relay connector.

    5. Reinstall the integration relay.

    REPAIR OR REPLACE HARNESS OR CONNECTOR (INTEGRATION RELAY (EFI MAIN RELAY) - BODY GROUND)

  7. CHECK HARNESS AND CONNECTOR (INTEGRATION RELAY (EFI MAIN RELAY) - ECM)

    1. Disconnect the ECM connector.

    2. Remove the integration relay from the engine room No. 1 relay block.

    3. Disconnect the integration relay connector.

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

      Standard Resistance (Check for Open)

      Tester Connection

      Condition

      Specified Condition

      1B-2 - A76-46 (MREL)

      Always

      Below 1 Ω

      Standard Resistance (Check for Short)

      Tester Connection

      Condition

      Specified Condition

      1B-2 or A76-46 (MREL) - Body ground

      Always

      10 kΩ or higher

    5. Reconnect the ECM connector.

    6. Reconnect the integration relay connector.

    7. Reinstall the integration relay.

    REPLACE ECM

    (Click here)

    REPAIR OR REPLACE HARNESS OR CONNECTOR (INTEGRATION RELAY (EFI MAIN RELAY) - ECM)

  8. INSPECT INTEGRATION RELAY (IG2 RELAY)

    1. Inspect the IG2 relay (Click here).

    REPLACE INTEGRATION RELAY

  9. CHECK HARNESS AND CONNECTOR (INTEGRATION RELAY (IG2 RELAY) - ECM)

    1. Disconnect the ECM connector.

    2. Remove the integration relay from the engine room No. 1 relay block.

    3. Disconnect the integration relay connector.

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

      Standard Resistance (Check for Open)

      Tester Connection

      Condition

      Specified Condition

      1A-4 - A76-6 (IGSW)

      Always

      Below 1 Ω

      Standard Resistance (Check for Short)

      Tester Connection

      Condition

      Specified Condition

      1A-4 or A76-6 (IGSW) - Body ground

      Always

      10 kΩ or higher

    5. Reconnect the ECM connector.

    6. Reconnect the integration relay connector.

    7. Reinstall the integration relay.

    REPAIR OR REPLACE HARNESS OR CONNECTOR (INTEGRATION RELAY (IG2 RELAY) - ECM)

  10. CHECK HARNESS AND CONNECTOR (INTEGRATION RELAY (IG2 RELAY) - BATTERY)

    1. Disconnect the cable from the negative (-) battery terminal.

    2. Disconnect the cable from the positive (+) battery terminal.

    3. Remove the integration relay from the engine room No. 1 relay block.

    4. Disconnect the integration relay connector.

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

      Standard Resistance (Check for Open)

      Tester Connection

      Condition

      Specified Condition

      1C-1 - Battery positive terminal

      Always

      Below 1 Ω

      Standard Resistance (Check for Short)

      Tester Connection

      Condition

      Specified Condition

      1C-1 or Battery positive terminal - Body ground

      Always

      10 kΩ or higher

    6. Reconnect the integration relay connector.

    7. Reinstall the integration relay.

    8. Reconnect the cable to the positive (+) battery terminal.

    9. Reconnect the cable to the negative (-) battery terminal.

    REPAIR OR REPLACE HARNESS OR CONNECTOR (INTEGRATION RELAY (IG2 RELAY) - BATTERY)

  11. CHECK HARNESS AND CONNECTOR (INTEGRATION RELAY (IG2 RELAY) - BODY GROUND)

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

    2. Disconnect the integration relay connector.

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

      Standard Resistance (Check for Open)

      Tester Connection

      Condition

      Specified Condition

      1A-2 - Body ground

      Always

      Below 1 Ω

    4. Reconnect the integration relay connector.

    5. Reinstall the integration relay.

    REPAIR OR REPLACE HARNESS OR CONNECTOR (INTEGRATION RELAY (IG2 RELAY) - BODY GROUND)

  12. CHECK IF VEHICLE IS EQUIPPED WITH ENTRY AND START SYSTEM

    1. Check if the vehicle is equipped with an entry and start system.

      Table 2. Result

      Result

      Proceed to

      w/o Entry and Start System

      A

      w/ Entry and Start System

      B

    CHECK HARNESS AND CONNECTOR (INTEGRATION RELAY - POWER MANAGEMENT CONTROL ECU)Click here

  13. CHECK HARNESS AND CONNECTOR (INTEGRATION RELAY (IG2 RELAY) - IGNITION SWITCH)

    1. Disconnect the ignition switch connector.

    2. Remove the integration relay from the engine room No. 1 relay block.

    3. Disconnect the integration relay connector.

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

      Standard Resistance (Check for Open)

      Tester Connection

      Condition

      Specified Condition

      1A-3 - H6-6 (IG2)

      Always

      Below 1 Ω

      Standard Resistance (Check for Short)

      Tester Connection

      Condition

      Specified Condition

      1A-3 or H6-6 (IG2) - Body ground

      Always

      10 kΩ or higher

    5. Reconnect the ignition switch connector.

    6. Reconnect the integration relay connector.

    7. Reinstall the integration relay.

    REPAIR OR REPLACE HARNESS OR CONNECTOR (INTEGRATION RELAY (IG2 RELAY) - IGNITION SWITCH)

  14. INSPECT IGNITION SWITCH ASSEMBLY

    1. Inspect the ignition switch assembly (Click here).

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

    REPLACE IGNITION SWITCH ASSEMBLY

    (Click here)

  15. CHECK HARNESS AND CONNECTOR (INTEGRATION RELAY - POWER MANAGEMENT CONTROL ECU)

    1. Disconnect the power management control ECU connector.

    2. Remove the integration relay from the engine room No. 1 relay block.

    3. Disconnect the integration relay connector.

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

      Standard Resistance (Check for Open)

      Tester Connection

      Condition

      Specified Condition

      1A-3 - H70-8 (IG2D)

      Always

      Below 1 Ω

      Standard Resistance (Check for Short)

      Tester Connection

      Condition

      Specified Condition

      1A-3 or H70-8 (IG2D) - Body ground

      Always

      10 kΩ or higher

    5. Reconnect the power management control ECU connector.

    6. Reconnect the integration relay connector.

    7. Reinstall the integration relay.

    CHECK ENTRY AND START SYSTEM

    (Click here)

    REPAIR OR REPLACE HARNESS OR CONNECTOR (INTEGRATION RELAY - POWER MANAGEMENT CONTROL ECU)