Diagnostic Procedure
WARNING: This page is about a different car, the 2003 Mazda 6. However, it is still accessible from the selected car via links, so may be relevant.
- If FREEZE FRAME DATA has been recorded, go to next step. If FREEZE FRAME DATA has not been recorded, record FREEZE FRAME DATA. Go to next step.
- Verify Related Repair Information Availability - Check for related Service Bulletins and/or on-line repair information availability. If any related repair information is available, perform repair or diagnosis according to available repair information. If vehicle is not repaired, go to next step. If related repair information is not available, go to next step.
- Inspect For Other DTCs - Turn ignition off, then on (engine off). If other DTCs have not been stored, go to next step. If other DTCs have been stored, repair circuit malfunction for applicable DTCs. Refer to DIAGNOSTIC TROUBLE CODE DEFINITIONS .
- Inspect EGR Valve Gasket Has Been Installed - Turn ignition off. Remove EGR valve. If EGR valve gasket is installed, go to next step. If EGR valve gasket is not present, install EGR valve gasket. After repair, go to step 6.
- Inspect EGR Valve Gasket Malfunction - If EGR valve gasket has any crack and/or damage, replace EGR valve gasket. After repair, go to next step. If EGR valve gasket is okay, go to next step.
- Monitor EGR System By Drive Mode 1 - Clear DTC from PCM memory using WDS or equivalent. Perform MODE 1 - PCM ADAPTIVE MEMORY PRODUCE DRIVE MODE under DRIVE CYCLES. Stop vehicle and access ON BOARD READINESS TEST to inspect DRIVE MODE completion status. Verify FUEL_EVAL PID status. If FUEL_EVAL PID changed to YES, go to next step. If FUEL_EVAL PID did not change to YES, retry this step.
- Monitor EGR System By Drive Mode 2 - Perform MODE 2 - EGR SYSTEM REPAIR VERIFICATION DRIVE MODE under DRIVE CYCLES. Stop vehicle and access ON BOARD READINESS TEST to inspect DRIVE MODE completion status. Verify FUEL_EVAL PID status. If FUEL_EVAL PID changed to YES, go to next step. If FUEL_EVAL PID did not change to YES, retry this step.
- Verify Trouble Shooting Of DTC P0401 Completed - Make sure to reconnect all disconnected connectors. Access DIAGNOSTIC MONITORING TEST RESULTS. Verify TEST #10:31:83 (EGR pressure variation) value. Is value within specification, go to next step. If value is not within specification, replace PCM. For PCM removal and installation, see POWERTRAIN CONTROL MODULE under COMPUTERIZED ENGINE CONTROLS in REMOVAL & INSTALLATION article. After repair, go to next step.
- Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See AFTER REPAIR PROCEDURE . If any DTCs are present, go to appropriate DTC inspection. Refer to DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no DTCs are present, trouble shooting is complete.