Diagnostic Procedure

WARNING: This page is about a different car, the 2003 Mazda Protege5 and 2003 Mazda Protege. However, it is still accessible from the selected car via links, so may be relevant.

Verify Related Repair Information Availability - Turn ignition off. Connect scan tool to DLC-2. Turn ignition on, engine off. Monitor for FREEZE FRAME DATA and ensure data has been recorded. Check service bulletins for repair information related to this DTC. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step 8.
Inspect Connection Of EGR Boost Sensor Connector - Turn ignition off. Verify EGR boost sensor 3-pin harness connector is connected securely. If connection is okay, go to next step. If connection is loose, reconnect EGR boost sensor 3-pin harness connector securely. After repair, go to step 8.
Inspect EGR Boost Sensor Connector For Poor Connection - Turn ignition off. Disconnect EGR boost sensor 3-pin harness connector. Check for poor connection due to damaged, pulled-out terminals, corrosion, etc. If connector is okay, go to next step. If fault is present, repair as necessary. After repair, go to step 8.
Verify EGR Boost Sensor Ground Circuit For Open Circuit - Check continuity between ground and EGR boost sensor 3-pin harness connector terminal "B" (Orange wire). See Figure. If continuity is present, go to next step. If continuity is not present, repair open circuit in Orange wire between EGR boost sensor 3-pin harness connector terminal "B" and PCM 104-pin harness connector terminal No. 91. After repair, go to step 8.
Check PCM Connector - Disconnect PCM 104-pin harness connector. See Figure. Check for poor connection due to damaged, pulled-out terminals, corrosion, etc. If connection is okay, go to next step. If problem is present, repair as necessary. After repair, go to step 8.
Verify EGR Boost Sensor Signal Circuit For Short To Reference Voltage Circuit - Check continuity between EGR boost sensor 3-pin harness connector terminals "A" (Red/Blue wire) and "C" (Pink/Black wire). If continuity is not present, go to next step. If continuity is present, repair suspect harness for short between circuits. See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to step 8.
Verify EGR Boost Sensor Signal Circuit For Open Circuit - Check continuity of Red/Blue wire between EGR boost sensor 3-pin harness connector terminal "A" and PCM 104-pin harness connector terminal No. 34. See Figure and Figure . If continuity is present, go to next step. If continuity is not present, repair open circuit in Red/Blue wire between EGR boost sensor 3-pin harness connector terminal "A" and PCM 104-pin harness connector terminal No. 34. See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to next step.
Verify Trouble Shooting Of DTC P0108 Completed - Reconnect all connectors. Turn ignition on, engine off. Clear DTCs. See CLEARING DIAGNOSTIC TROUBLE CODES under SELF-DIAGNOSTIC SYSTEM. Start engine. Check for DTCs. See RETRIEVING DIAGNOSTIC TROUBLE CODES under SELF-DIAGNOSTIC SYSTEM. If DTC P0108 is present, replace PCM. For PCM removal and installation, see POWERTRAIN CONTROL MODULE under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION article. After repair, go to next step. If same DTC P0108 is not present, go to next step.
Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See AFTER REPAIR PROCEDURE . If no other DTCs are present, testing is complete. If any other DTC is present, follow appropriate DTC diagnostic procedure. See DIAGNOSTIC TROUBLE CODE DEFINITIONS .