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Home › Mazda › 2003 › Protege5 Automatic › Repair and Diagnosis › Engine Performance › System › Engine Controls - Self-Diagnostics › Diagnostic Tests › DTC P0451: Fuel Tank Pressure Sensor - Performance Problem › Diagnostic Procedure

Diagnostic Procedure

  1. 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  7.
  2. Inspect For Other DTCs -  Turn ignition off, then start engine. Using scan tool, check for DTCs. See RETRIEVING DIAGNOSTIC TROUBLE CODES  under SELF-DIAGNOSTIC SYSTEM. If DTCs P0443 or P1449 are present, diagnose and repair these DTCs first. See DTC P0443: EVAP CONTROL SYSTEM PURGE CONTROL VALVE - CIRCUIT MALFUNCTION  or DTC P1449: CANISTER DRAIN CUT VALVE (CDCV) - OPEN OR SHORT  . If DTCs P0443 and P1449 are not present, go to next step.
  3. Inspect Purge Solenoid Valve Operation -  Inspect purge solenoid valve. See FUEL EVAPORATIVE SYSTEM (EXCEPT MIATA & MPV) under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If purge solenoid valve is okay, go to next step. If purge solenoid valve is faulty, replace purge solenoid valve. After repair, go to step  7.
  4. Inspect CDCV Operation -  Inspect CDCV. See FUEL EVAPORATIVE SYSTEM (EXCEPT MIATA & MPV) under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If CDCV operates properly, go to next step. If CDCV does not operate properly, replace CDCV. After repair, go to step  7.
  5. Inspect Charcoal Canister For Clogging -  Turn ignition off. Remove charcoal canister beside fuel tank. Inspect for plugging. If charcoal canister is okay, go to next step. If charcoal canister is plugged, replace canister. After repair, go to step  7.
  6. Inspect Fuel Tank Pressure Sensor -  Inspect FTP sensor. See FUEL TANK PRESSURE SENSOR under ENGINE SENSORS & SWITCHES in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If FTP sensor is okay, go to next step. If FTP sensor is faulty, replace FTP sensor. After repair, go to next step.
  7. Verify Monitoring Condition For Evaporative System Test -  Turn ignition on, engine off. Using scan tool, access BARO, ECT, TP and IAT PIDs. PID data should read:
    • BARO: more than 21.3 in. Hg.
    • ECT: 14-95°F (-10-35°C) when vehicle is first started.
    • IAT: 14-140°F (-10-60°C).
    • TP: 15-85 percent with vehicle load at 9-65 percent and vehicle speed at 24.5-65.4 MPH.

    If any PIDs are not within specification, allow engine to cool down and repeat this step. If all PIDs are within specification, go to next step.

  8. Monitor EVAP System By Drive Mode 4 -  Reconnect all connectors. Perform EVAP system repair verification drive mode. See MODE 4 - EVAP SYSTEM REPAIR VERIFICATION DRIVE MODE  under SELF-DIAGNOSTIC SYSTEM. Access ON BOARD SYSTEM READINESS TEST menu of GENERIC OBD II FUNCTION and check DRIVE MODE completion status. If evaporative purge system monitor is complete, go to next step. If evaporative purge system monitor is not complete, go back to step  7.
  9. Verify Trouble Shooting Of DTC P0451 Completed -  Turn ignition on, engine off. Using scan tool, clear DTCs. See RETRIEVING DIAGNOSTIC TROUBLE CODES  under SELF-DIAGNOSTIC SYSTEM. If DTC P0451 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 P0451 is not present, go to next step.
  10. 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 .
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