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Diagnostic procedure

WARNING: This page is about a different car, the 2005 Mazda 6. However, it is still accessible from the selected car via links, so may be relevant.
DTC P0403 [L3] DIAGNOSTIC PROCEDURE

STEP INSPECTION ACTION
1 VERIFY FREEZE FRAME DATA HAS BEEN RECORDED 
  • Has FREEZE FRAME DATA been recorded?
 Yes Go to the next step.
No Record FREEZE FRAME DATA on repair order, then go to the next step.
2 VERIFY RELATED REPAIR INFORMATION AVAILABILITY 
  • Check for related Service Bulletins and/or online 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 FOR POOR CONNECTION 
  • Turn the ignition switch off.
  • Disconnect EGR valve connector.
  • Inspect for poor connection (such as damaged/pulled-out pins, corrosion).
  • Is there any malfunction?
 Yes Repair or replace terminals and/or connector, then go to Step 10.
No Go to the next step.
4 INSPECT POWER CIRCUIT FOR OPEN CIRCUIT 
  • Turn ignition switch to ON (Engine off).
  • Measure voltage following terminal and body ground.
    • EGR valve terminal C (harness-side)
    • EGR valve terminal D (harness-side)
  • Is voltage B+  ?
 Yes Go to the next step.
No Repair or replace harness for open circuit then go to Step 10.
5 INSPECT EGR VALVE 
 Yes Go to the next step.
No Replace EGR valve, then go to Step 10.
6 INSPECT FOR CONTROL CIRCUIT FOR SHORT TO GROUND 
  • Turn the ignition switch off.
  • Inspect continuity following terminal and body ground:
    • EGR valve terminal E (harness-side)
    • EGR valve terminal A (harness-side)
    • EGR valve terminal B (harness-side)
    • EGR valve terminal F (harness-side)
  • Is there continuity?
 Yes Repair or replace harness for short to ground, then go to Step 10.
No Go to the next step.
7 INSPECT FOR CONTROL CIRCUIT FOR SHORT TO POWER SUPPLY 
  • Turn ignition switch ignition switch to ON (Engine off).
  • Measure voltage following terminal and body ground:
    • EGR valve terminal E (harness-side)
    • EGR valve terminal A (harness-side)
    • EGR valve terminal B (harness-side)
    • EGR valve terminal F (harness-side)
  • Is voltage B+  ?
 Yes Repair or replace harness for short to power supply, then go to Step 10.
No Go to the next step.
8 INSPECT PCM CONNECTOR FOR POOR CONNECTION 
  • Turn the ignition switch off.
  • Disconnect PCM connector.
  • Inspect for poor connection (such as damaged/pulled-out pins, corrosion).
  • Is there any malfunction?
 Yes Repair or replace terminals and/or connector, then go to Step 10.
No Go to the next step.
9 INSPECT CONTROL CIRCUIT FOR OPEN CIRCUIT 
  • Remove PCM with PCM connector connected.
  • Inspect continuity following terminals (harness-side):
    • Between EGR valve terminal E and PCM terminal 98(1), 4E(2)
    • Between EGR valve terminal A and PCM terminal 99(1), 4H(2)
    • Between EGR valve terminal B and PCM terminal 72(1), 4K(2)
    • Between EGR valve terminal F and PCM terminal 73(1), 4N(2)
  • Is there continuity?
 Yes Go to the next step.
No Repair or replace harness for open circuit then go to the next step.
10 VERIFY TROUBLESHOOTING OF DTC P0403 COMPLETED 
  • Make sure to reconnect all disconnected connectors.
  • Clear the DTC from the PCM memory using the WDS or equivalent.
  • Turn the ignition switch off.
  • Start engine and warm it up completely.
  • Is PENDING CODE for this DTC present?
 Yes Replace PCM, then go to the next step. (See PCM REMOVAL/INSTALLATION .)
No Go to the next step.
11 VERIFY AFTER REPAIR PROCEDURE 
 Yes Go to the applicable DTC inspection. (See DTC TABLE .)
No Troubleshooting completed.
(1) California emission regulation applicable ATX model
(2) Except for California emission regulation applicable ATX model
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