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Home >> Toyota >> 2019 >> Yaris LE >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - Diagnostic Codes (9 Of 13) >> SFI System >> DTC P0685-00: ECM/PCM Power Relay Control Circuit/Open [07/2015 - 08/2018] >> Procedure
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DTC P0685-00: ECM/PCM Power Relay Control Circuit/Open [07/2015 - 08/2018]: Procedure

  1. INSPECT MAIN RELAY 
    1. Switch the ignition off.
    2. Remove the main relay.

      Refer to INSPECTION [07/2015 - 08/2018]

    3. Inspect the main relay.

      Refer to INSPECTION [07/2015 - 08/2018]

    4. Is there any malfunction?

      Result

      Result
      Yes
      No

    Result: 

    Yes 

    See step  18

    Result: 

    No 

    See step  2

  2. INSPECT MAIN RELAY POWER SUPPLY CIRCUIT FOR SHORT TO GROUND OR OPEN CIRCUIT 
    1. Main relay is removed.
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      Main relay terminal 3 - Body ground Always 11 to 14 V

      Result

      Result
      Yes
      No

    Result: 

    No 

    See step  17

    Result: 

    Yes 

    See step  3

  3. INSPECT ENGINE2 15 A FUSE 
    1. Remove the ENGINE2 15 A fuse.
    2. Inspect the ENGINE2 15 A fuse.
    3. Is there any malfunction?

      Result

      Result
      Yes
      No

    Result: 

    No 

    See step  15

    Result: 

    Yes 

    See step  16

  4. INSPECT ECM POWER SUPPLY CIRCUIT FOR SHORT TO GROUND 
    1. Main relay is removed.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      Main relay terminal 5 - Body ground Always 10 kΩ or higher

      Result

      Result
      Yes
      No

    Result: 

    No 

    See step  14

    Result: 

    Yes 

    See step  5

  5. INSPECT ECM CONNECTOR CONDITION 
    1. Disconnect the ECM connector.
    2. Inspect for poor connection (such as damaged/pulled-out pins, corrosion).
    3. Is there any malfunction?

      Result

      Result
      Yes
      No

    Result: 

    Yes 

    See step  13

    Result: 

    No 

    See step  6

  6. INSPECT ECM GROUND CIRCUIT FOR OPEN CIRCUIT 
    1. Main relay is removed.
    2. Verify that the ECM connector is disconnected.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      C27-46 - Body ground Always Below 1 Ω
      A42-7 - Body ground Always Below 1 Ω

      Result

      Result
      Yes
      No

    Result: 

    No 

    See step  12

    Result: 

    Yes 

    See step  7

  7. INSPECT ECM POWER SUPPLY CIRCUIT FOR OPEN CIRCUIT 
    1. Main relay is removed.
    2. Verify that the ECM connector is disconnected.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      Main relay terminal 5 - A42-5 Always Below 1 Ω
      Main relay terminal 5 - A42-18 Always Below 1 Ω

      Result

      Result
      Yes
      No

    Result: 

    No 

    See step  11

    Result: 

    Yes 

    See step  8

  8. VERIFY DTC TROUBLESHOOTING COMPLETED 
    1. Always reconnect all disconnected connectors.
    2. Clear the DTC from the ECM memory using the Techstream.

      Refer to AFTER REPAIR PROCEDURE [07/2015 - ]

      Powertrain > Engine > Clear DTCs 

    3. Start the engine and warm it up completely.
    4. Perform the Pending Trouble Code Access Procedure.

      Refer to ON-BOARD DIAGNOSTIC TEST [07/2015 - ]

      Powertrain > Engine > Trouble Codes 

    5. Is the PENDING CODE for this DTC present?

      Result

      Result
      Yes
      No

    Result: 

    Yes 

    See step  10

    Result: 

    No 

    See step  9

  9. VERIFY AFTER REPAIR PROCEDURE 
    1. Perform the "AFTER REPAIR PROCEDURE".

      Refer to AFTER REPAIR PROCEDURE [07/2015 - ]

    2. Are any DTCs present?

      Result

      Result
      Yes
      No

    Result: 

    No 

    DTC TROUBLESHOOTING COMPLETED. 

    Result: 

    Yes 

    GO TO THE APPLICABLE DTC INSPECTION. 

    1. Refer to DIAGNOSTIC TROUBLE CODE CHART [07/2015 - 08/2018]
  10. REPEAT THE INSPECTION FROM STEP 1. 
    1. If the malfunction recurs, replace the ECM.

      Refer to REMOVAL [07/2015 - ]

    2. Go to the next step.

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  9

  11. REFER TO THE WIRING DIAGRAM AND VERIFY WHETHER OR NOT THERE IS A COMMON CONNECTOR BETWEEN THE FOLLOWING TERMINALS: 
    • Main relay terminal 5-ECM terminal A42-5
    • Main relay terminal 5-ECM terminal A42-18

    If there is a common connector: 

    • Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for an open circuit.
    • Repair or replace the malfunctioning part.

    If there is no common connector: 

    • Repair or replace the wiring harness which has an open circuit.
    1. Go to the next step.

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  8

  12. REFER TO THE WIRING DIAGRAM AND VERIFY WHETHER OR NOT THERE IS A COMMON CONNECTOR BETWEEN THE FOLLOWING TERMINALS: 
    • ECM terminal C27-46 (wiring harness-side)-Body ground
    • ECM terminal A42-7 (wiring harness-side)-Body ground

    If there is a common connector: 

    • Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for an open circuit.
    • Repair or replace the malfunctioning part.

    If there is no common connector: 

    • Inspect for the following:
      • Open circuit between ECM and body ground
      • Loose or lifting ground point
        1. Repair or replace the malfunctioning part.
    1. Go to the next step.

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  8

  13. REPAIR OR REPLACE THE CONNECTOR AND/OR TERMINALS. 
    1. Then go to the next step.

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  8

  14. DISCONNECT THE ECM CONNECTOR. 
    1. If the short to ground circuit could be detected in the wiring harness:
      1. Refer to the wiring diagram and verify whether or not there is a common connector between the following terminals:
        • Main relay terminal 5-ECM terminal A42-5
        • Main relay terminal 5-ECM terminal A42-18

        If there is a common connector: 

        • Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for a short to ground.
        • Repair or replace the malfunctioning part.

        If there is no common connector: 

        • Repair or replace the wiring harness which has a short to ground.
    2. If the short to ground circuit could not be detected in the wiring harness:
      1. Replace the ECM (short to ground in the ECM internal circuit).

        Refer to REMOVAL [07/2015 - ]

    3. Go to the next step.

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  8

  15. REINSTALL THE ENGINE2 15 A FUSE. 
    1. Then go to the next step.

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  4

  16. IF THE FUSE IS BLOWN: 
    1. If the fuse is blown:
      1. Refer to the wiring diagram and verify whether or not there is a common connector between the following terminals:
        • Main relay terminal 5-ECM terminal A42-5
        • Main relay terminal 5-ECM terminal A42-18

        If there is a common connector: 

        • Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for a short to ground.
        • Repair or replace the malfunctioning part.

        If there is no common connector: 

        • Repair or replace the wiring harness which has a short to ground.
        • Replace the fuse.
    2. If the fuse is damaged:
      1. Replace the fuse.
    3. Go to the next step.

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  8

  17. INSPECT THE MAIN 200 A FUSE AND ENG.MAIN 40 A FUSE. 
    1. If the fuse is blown:
      1. Refer to the wiring diagram and verify whether or not there is a common connector between MAIN 200 A fuse and main relay terminal 3.

        If there is a common connector: 

        • Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for a short to ground.
        • Repair or replace the malfunctioning part.

        If there is no common connector: 

        • Repair or replace the wiring harness which has a short to ground.
        • Replace the malfunctioning fuse.
    2. If the fuse is damaged:
      1. Replace the malfunctioning fuse.
    3. If all fuses are normal:
      1. Refer to the wiring diagram and verify whether or not there is a common connector between battery positive terminal and main relay terminal 3.

        If there is a common connector: 

        • Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for an open circuit.
        • Repair or replace the malfunctioning part.

        If there is no common connector: 

        • Repair or replace the wiring harness which has an open circuit.
    4. Go to the next step.

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  8

  18. REPLACE THE MAIN RELAY. 
    1. Then go to the next step.

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  8

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