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Home › Mazda › 2002 › Protege5 Standard › Repair and Diagnosis › Engine Performance › System › Engine Controls - Self-Diagnostics › Diagnostic Tests › DTC P0451: Fuel Tank Pressure Sensor, Performance Problem › Diagnosis & Repair Procedure

Diagnosis & Repair Procedure

  1. 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.
  2. Turn ignition switch off and 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. Disconnect purge solenoid valve hoses. Connect vacuum pump to purge solenoid valve port and apply vacuum. Valve should hold vacuum. Using fused jumper wires, connect battery voltage to purge solenoid valve. If purge solenoid valve releases vacuum, go to next step. If purge solenoid valve does not release vacuum, replace purge solenoid valve. After repair, go to step  7.
  4. Inspect CDCV. See FUEL EVAPORATIVE SYSTEM - EXCEPT MPV under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - MIATA, MILLENIA, MPV, PROTEGE, PROTEGE5 & 626 article. If CDCV operates properly, go to next step. If CDCV does not operate properly, replace CDCV. After repair, go to step  7.
  5. Turn ignition switch 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 FTP sensor. See FUEL TANK PRESSURE SENSOR in SYSTEM & COMPONENT TESTING - MIATA, MILLENIA, MPV, PROTEGE, PROTEGE5 & 626 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. Turn ignition switch 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. Reconnect all connectors. Perform EVAP system repair verification drive mode. See DRIVE MODE 4 - EVAP SYSTEM REPAIR VERIFICATION  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, repeat previous step.
  9. Turn ignition switch on, engine off. Check for DTCs. See RETRIEVING DIAGNOSTIC TROUBLE CODES  under SELF-DIAGNOSTIC SYSTEM. If DTC P0451 is present, replace PCM. After repair, go to next step. If DTC P0451 is not present, go to next step.
  10. Cycle ignition switch from off to on. Check for DTCs. See RETRIEVING DIAGNOSTIC TROUBLE CODES  under SELF-DIAGNOSTIC SYSTEM. If no other DTCs are present, testing is complete. If any other DTC is present, go to applicable test and repair.
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