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Home >> Mazda >> 2017 >> CX-5 Grand Select, FWD >> Repair and Diagnosis >> Engine Performance >> System >> On-Board Diagnostic - Engine Control System (2 Of 5) >> DTC P0685-00: Main Relay Control Circuit Open >> Diagnostic Procedure
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Diagnostic Procedure

DIAGNOSTIC PROCEDURE DESCRIPTION

STEP INSPECTION RESULTS ACTION
1 RECORD VEHICLE STATUS AT TIME OF DTC DETECTION TO UTILIZE WITH REPEATABILITY VERIFICATION
NOTE:
  • Recording can be facilitated using the screen capture function of the PC.
  • Record the FREEZE FRAME DATA/snapshot data on the repair order.
- Go to the next step.
2 VERIFY RELATED REPAIR INFORMATION AVAILABILITY
  • Verify related Service Bulletins and/or on-line repair information availability.
  • Is any related repair information available?
Yes Perform repair or diagnosis according to the available repair information.
  • If the vehicle is not repaired, go to the next step.
No Go to the next step.
3 INSPECT MAIN RELAY Yes Replace the main relay, then go to Step 10.
No Go to the next step.
4 INSPECT MAIN RELAY POWER SUPPLY CIRCUIT FOR SHORT TO GROUND OR OPEN CIRCUIT
  • Main relay is removed.
  • Measure the voltage at the main relay terminal D (wiring harness-side).
  • Is the voltage B+?
Yes Go to the next step.
No Inspect the MAIN 200 A fuse and ENG.MAIN 40 A fuse.
  • If the fuse is blown:
    • Refer to the wiring diagram and verify whether or not there is a common connector between MAIN 200 A fuse and main relay terminal D.

If there is a common connector:
  • Determine the malfunctioning part by inspecting the common connector and the 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.
    • If the fuse is damaged:
      • Replace the malfunctioning fuse.
  • If all fuses are normal:
    • Refer to the wiring diagram and verify whether or not there is a common connector between battery positive terminal and main relay terminal D.

    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.

Go to Step 10.
5 INSPECT ENGINE2 15 A FUSE
  • Remove the ENGINE2 15 A fuse.
  • Inspect the ENGINE2 15 A fuse.
  • Is there any malfunction?
Yes If the fuse is blown:
  • Refer to the wiring diagram and verify whether or not there is a common connector between the following terminals:
    • Main relay terminal C-PCM terminal 2S
      • Main relay terminal C-PCM terminal 2T

      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.

    If the fuse is damaged:

  • Replace the fuse.

Go to Step 10.
No Reinstall the ENGINE2 15 A fuse, then go to the next step.
6 INSPECT PCM POWER SUPPLY CIRCUIT FOR SHORT TO GROUND
  • Main relay is removed.
  • Inspect for continuity between main relay terminal C (wiring harness-side) and body ground.
  • Is there continuity?
Yes Disconnect the PCM connector and inspect the wiring harness for short to ground.
  • If the short to ground circuit could be detected in the wiring harness:
    • Refer to the wiring diagram and verify whether or not there is a common connector between the following terminals:
  • Main relay terminal C-PCM terminal 2S
    • Main relay terminal C-PCM terminal 2T

    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:


Go to Step 10.
No Go to the next step.
7 INSPECT PCM CONNECTOR CONDITION
  • Disconnect the PCM connector.
  • Inspect for poor connection (such as damaged/pulled-out pins, corrosion).
  • Is there any malfunction?
Yes Repair or replace the connector and/or terminals, then go to Step 10.
No Go to the next step.
8 INSPECT PCM GROUND CIRCUIT FOR OPEN CIRCUIT
  • Main relay is removed.
  • Verify that the PCM connector is disconnected.
  • Inspect for continuity between the following harnesses:
    • PCM terminal 1BZ (wiring harness-side)-Body ground
      • PCM terminal 2AA (wiring harness-side)-Body ground
  • Is there continuity?
Yes Go to the next step.
No Refer to the wiring diagram and verify whether or not there is a common connector between the following terminals:
  • PCM terminal 1BZ (wiring harness-side)-Body ground
  • PCM terminal 2AA (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 PCM and body ground
    • Loose or lifting ground point
      • Repair or replace the malfunctioning part.

Go to Step 10.
9 INSPECT PCM POWER SUPPLY CIRCUIT FOR OPEN CIRCUIT
  • Main relay is removed.
  • Verify that the PCM connector is disconnected.
  • Inspect for continuity between the following terminals (wiring harness-side):
    • Main relay terminal C-PCM terminal 2S
      • Main relay terminal C-PCM terminal 2T
  • Is there continuity?
Yes Go to the next step.
No Refer to the wiring diagram and verify whether or not there is a common connector between the following terminals:
  • Main relay terminal C-PCM terminal 2S
  • Main relay terminal C-PCM terminal 2T

    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.

Go to the next step.
10 VERIFY DTC TROUBLESHOOTING COMPLETED
  • Always reconnect all disconnected connectors.
  • Clear the DTC from the PCM memory using the M-MDS. (See CLEARING DTC [PCM (SKYACTIV-G 2.0, SKYACTIV-G 2.5)].)
  • Start the engine and warm it up completely.
  • Perform the Pending Trouble Code Access Procedure. (See ON-BOARD DIAGNOSTIC TEST [PCM (SKYACTIV-G 2.0, SKYACTIV-G 2.5)] .)
  • Is the PENDING CODE for this DTC present?
Yes Repeat the inspection from Step 1.
  • If the malfunction recurs, replace the PCM.

(See PCM REMOVAL/INSTALLATION [SKYACTIV-G 2.0, SKYACTIV-G 2.5] .)
Go to the next step.
No Go to the next step.
11 VERIFY AFTER REPAIR PROCEDURE Yes Go to the applicable DTC inspection.
(See DTC TABLE [PCM (SKYACTIV-G 2.0, SKYACTIV-G 2.5)] .)
No DTC troubleshooting completed.