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Home >> Mazda >> 2021 >> CX-9 Signature >> Repair and Diagnosis >> Engine Performance >> System >> On-Board Diagnostic - Engine Control System (3 Of 6) >> DTC P0403-00: EGR Valve Control Circuit Problem >> Diagnostic Procedure
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Diagnostic Procedure

DTC P0403:00 DIAGNOSTIC PROCEDURE

STEP INSPECTION 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 EGR VALVE CONNECTOR CONDITION
  • Switch the ignition off.
  • Disconnect the EGR valve 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 11.
No Go to the next step.
4 INSPECT EGR VALVE POWER SUPPLY CIRCUIT FOR SHORT TO GROUND OR OPEN CIRCUIT
  • Verify that the EGR valve connector is disconnected.
  • Switch the ignition ON (engine off).
    NOTE:
    • Another DTC may be stored by the PCM detecting an open circuit.
  • Measure the voltage at the following terminals (wiring harness-side):
    • EGR valve terminal C
    • EGR valve terminal D
  • Is the voltage B+?
 Yes Go to the next step.
No Inspect the ENGINE 1 15 A fuse.
  • If the fuse is blown:
    • Refer to appropriate wiring diagram and verify whether or not there is a common connector between the following terminals:
  • ENGINE1 15 A fuse-EGR valve terminal C
  • ENGINE1 15 A fuse-EGR valve 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 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.
  • If the fuse is normal:
    • Refer to appropriate wiring diagram and verify whether or not there is a common connector between the following terminals:
      • Main relay terminal C-EGR valve terminal C
      • Main relay terminal C-EGR valve 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 11.
5 INSPECT EGR VALVE CIRCUIT FOR SHORT TO GROUND
  • Verify that the EGR valve connector is disconnected.
  • Switch the ignition off.
  • Inspect for continuity between the following terminals (wiring harness-side) and body ground:
    • EGR valve terminal A
    • EGR valve terminal E
    • EGR valve terminal B
    • EGR valve terminal F
  • 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 appropriate wiring diagram and verify whether or not there is a common connector between the following terminals:
      • EGR valve terminal A-PCM terminal 1J
      • EGR valve terminal E-PCM terminal 1Y
      • EGR valve terminal B-PCM terminal 1O
      • EGR valve terminal F-PCM terminal 1T

    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.
  • If the short to ground circuit could not be detected in the wiring harness:

Go to Step 11.
No Go to the next step.
6 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 11.
No Go to the next step.
7 INSPECT EGR VALVE CIRCUIT FOR SHORT TO POWER SUPPLY
  • Verify that the EGR valve and PCM connectors are disconnected.
  • Switch the ignition ON (engine off).
    NOTE:
    • Another DTC may be stored by the PCM detecting an open circuit.
  • Measure the voltage at the following terminals (wiring harness-side):
    • EGR valve terminal A
    • EGR valve terminal E
    • EGR valve terminal B
    • EGR valve terminal F
  • Is the voltage 0 V?
 Yes Go to the next step.
No Refer to appropriate wiring diagram and verify whether or not there is a common connector between the following terminals:
  • EGR valve terminal A-PCM terminal 1J
  • EGR valve terminal E-PCM terminal 1Y
  • EGR valve terminal B-PCM terminal 1O
  • EGR valve terminal F-PCM terminal 1T

    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 power supply.
  • Repair or replace the malfunctioning part. If there is no common connector:
  • Repair or replace the wiring harness which has a short to power supply.

Go to Step 11.
8 INSPECT EGR VALVE CIRCUITS FOR SHORT TO EACH OTHER
  • Verify that the EGR valve and PCM connectors are disconnected.
  • Switch the ignition off.
  • Inspect for continuity EGR valve terminals A, E, B and F (wiring harness-side).
  • Is there continuity?
 Yes Refer to appropriate wiring diagram and verify whether or not there is a common connector between the following terminals:
  • EGR valve terminal A-PCM terminal 1J
  • EGR valve terminal E-PCM terminal 1Y
  • EGR valve terminal B-PCM terminal 1O
  • EGR valve terminal F-PCM terminal 1T

    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 each other.
  • Repair or replace the malfunctioning part. If there is no common connector:
  • Repair or replace the wiring harness which has a short to each other.

Go to Step 11.
No Go to the next step.
9 INSPECT EGR VALVE CIRCUIT FOR OPEN CIRCUIT
  • Verify that the EGR valve and PCM connectors are disconnected.
  • Inspect for continuity between the following terminals (wiring harness-side):
    • EGR valve terminal A-PCM terminal 1J
    • EGR valve terminal E-PCM terminal 1Y
    • EGR valve terminal B-PCM terminal 1O
    • EGR valve terminal F-PCM terminal 1T
  • Is there continuity?
 Yes Go to the next step.
No Refer to appropriate wiring diagram and verify whether or not there is a common connector between the following terminals:
  • EGR valve terminal A-PCM terminal 1J
  • EGR valve terminal E-PCM terminal 1Y
  • EGR valve terminal B-PCM terminal 1O
  • EGR valve terminal F-PCM terminal 1T 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 11.
10 INSPECT EGR VALVE
 Yes Replace the EGR valve, then go to the next step.
(See EGR VALVE REMOVAL/INSTALLATION [SKYACTIV-G 2.5T] .)
No Go to the next step.
11 VERIFY DTC TROUBLESHOOTING COMPLETED
 Yes Repeat the inspection from Step 1.

Go to the next step.
No Go to the next step.
12 VERIFY AFTER REPAIR PROCEDURE
 Yes Go to the applicable DTC inspection. (See DTC TABLE [PCM (SKYACTIV-G 2.5T)] .)
No DTC troubleshooting completed.
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