ECD SYSTEM(w/o Glow Plug Controller), Diagnostic DTC:P0685

DTC Code DTC Name
P0685 ECM / PCM Power Relay Control Circuit / Open

DESCRIPTION

The battery supplies power to terminal +B and/or +B2 of the ECM even when the ignition switch is turned to off (up to 20 seconds).

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

MIL

Memory

P0685

ECM / PCM Power Relay Control Circuit / Open

Either of following conditions is met:

(1 trip detection logic)

  • After ignition switch is turned to off, voltage supplied to terminal +B and/or +B2 is cut earlier than the minimum threshold duration.

  • After ignition switch is turned to off, voltage supplied to terminal +B and/or +B2 continues after the threshold duration has elapsed.

  • Open in EFI-MAIN relay circuit

  • EFI-MAIN relay

  • EFI-MAIN fuse

  • ECM

-

DTC stored
Table 1. DTC Detection Drive Pattern

DTC No.

DTC Detection Drive Pattern

P0685

After ignition switch is turned to off

WIRING DIAGRAM

A293503E01

CAUTION / NOTICE / HINT

Note:

  • When replacing the ECM, perform ECM Initialization and Registration.

    Click hereClick here

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

Tip:

  • When the ECM must be replaced, before replacing the ECM, perform the "Learning Values Save" function using the GTS. Then after installing a new ECM, perform all of the initialization and registration procedures for the "Learning Values Write" function by following the instructions shown on the GTS display.

  • Read freeze frame data using the GTS. Freeze frame data records the engine condition when malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, and other data from the time the malfunction occurred.

PROCEDURE

  1. INSPECT RELAY (EFI-MAIN RELAY)

    1. Inspect the EFI-MAIN relay.

      Click here

    Result

    Proceed to

    OK

    NG
    NG

    REPLACE RELAY (EFI-MAIN RELAY)Click here

    OK

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

    1. Remove the EFI-MAIN relay from engine room relay block and junction block assembly.

    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

      EFI-MAIN relay terminal 1 - A101-22 (MREL)

      Always

      Below 1 Ω

      EFI-MAIN relay terminal 3 - A101-1 (+B)

      Always

      Below 1 Ω

      EFI-MAIN relay terminal 3 - A101-61 (+B2)

      Always

      Below 1 Ω

      EFI-MAIN relay terminal 1 or A101-22 (MREL) - Body ground

      Always

      10 kΩ or higher

      EFI-MAIN relay terminal 3 or A101-1 (+B) - Body ground

      Always

      10 kΩ or higher

      EFI-MAIN relay terminal 3 or A101-61 (+B2) - Body ground

      Always

      10 kΩ or higher

    Result

    Proceed to

    OK

    NG
    NG

    REPAIR OR REPLACE HARNESS OR CONNECTORClick here

    OK

  3. REPLACE ECM

    1. Replace the ECM.

      Click here

    Result

    Proceed to

    NEXT
    NEXT

  4. CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED

    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON and turn the GTS on.

    3. Clear the DTCs.

      Powertrain > Engine and ECT > Clear DTCs

    4. Turn the ignition switch off and wait for 30 seconds or more.

    5. Turn the ignition switch to ON.

    6. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.

    7. Confirm that the DTC is not output again.

      Powertrain > Engine and ECT > Trouble Codes

    Result

    Proceed to

    NEXT
    NEXT

    END

  5. REPAIR OR REPLACE HARNESS OR CONNECTOR

    Result

    Proceed to

    NEXT
    NEXT

    CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIREDClick here

  6. REPLACE RELAY (EFI-MAIN RELAY)

    1. Replace the EFI-MAIN relay.

    Result

    Proceed to

    NEXT
    NEXT

    CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIREDClick here