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Home >> Mazda >> 2002 >> Tribute LX, 4WD >> Repair and Diagnosis >> External Pages >> Different car >> Section 69 (Engine Controls - Self-Diagnostics) >> Diagnostic Tests >> DTC P0442 Or DTC P0456 >> Diagnostic Procedures

Diagnostic Procedures

WARNING: This page is about a different car, the 2003 Mazda Tribute. However, it is still accessible from the selected car via links, so may be relevant.
    NOTE: EVAP canister purge valve may also be referred to as EVAP vapor management valve.
  1. If QUICK TEST was not performed, go to QUICK TEST  under SELF-DIAGNOSTIC SYSTEM. If QUICK TEST was performed, go to next step.
  2. Visually Inspect Components For Small Leaks -  Check for presence of fuel filler cap. DO NOT tighten or check for correct installation at this time. Verify that Canister Vent (CV) solenoid is properly seated on EVAP canister. Visually inspect for cut or loose connections to fuel vapor hoses/tubes in following locations:
    • EVAP canister to EVAP canister purge valve.
    • EVAP canister to evaporative emission valve assembly.
    • Evaporative emission valve assembly to fuel tank (if applicable).

    Check for fuel filler pipe damage. If concern with a hose, tube, connection, or valve is visually evident, repair or install NEW component as necessary. After repair, go to step  10. If no problems are found, go to next step.

  3. Check For Small System Leaks From EVAP Test Port -  Connect EVAP System Leak Tester to EVAP test port. Perform EVAP System Leak Test. Refer to EVAPORATIVE EMISSIONS SYSTEM LEAK TEST under FUEL EVAPORATIVE SYSTEM under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - B2300, B3000, B4000 & TRIBUTE article. If EVAP system passed leak test, go to next step. If EVAP system failed leak test, go to step  5.
  4. Check For Small Leaks At Fuel Filler Cap & EVAP Test Port -  Connect EVAP System Leak Tester to fuel filler pipe. Turn ignition on, engine off. Close EVAP Canister Vent (CV) solenoid using EVAPCV PID. Using scan tool, select DIAGNOSTIC DATA LINK. Select PCM. Select ACTIVE COMMAND modes. Select OUTPUT TEST mode. Pressurize EVAP system to 14 in. H2O (3.48 kPa). Using ultrasonic leak detector, check for leaks around fuel filler cap and EVAP test port. If a leak is detected, repair or replace component as necessary. After repair, go to step  9. If a leak is not detected, remove leak tester. Install fuel filler cap. After repair, go to step  11.
  5. Visually Inspect Fuel Filler Cap -  Visually inspect fuel filler cap for damage. If fuel filler cap is okay, go to next step. If fuel filler cap is damaged, install NEW filler cap. After repair, go to step  10.
  6. Check For Small Leak With Tester Set At FILL Position -  Turn ignition on, engine off. Close EVAP Canister Vent (CV) solenoid using EVAPCV PID from OUTPUT TEST mode on scan tool. Pressurize EVAP system to 14 in. H2O (3.48 kPa). If pressure holds between 13.80 and 14.20 in. H2O (3.43 and 3.53 kPa), go to next step. If pressure does not hold as specified, go to step  8.
  7. Check For Leaks In Complete EVAP System -  Verify EVAP Canister Vent (CV) solenoid is closed. Verify system is pressurized to 14 in. H2O (3.48 kPa). Using ultrasonic leak detector, check following EVAP system locations:
    • EVAP return tube to EVAP canister purge valve.
    • EVAP canister purge valve to EVAP CV solenoid assembly.
    • EVAP CV solenoid assembly to fuel tank.
    • Fuel filler cap and fuel filler pipe.
    If no leak is detected, discontinue pressurizing system. Go to next step. If a leak is detected, repair or install NEW component as necessary. After repair, go to step  10.
  8. Check For Small Leak From EVAP Return Tube To EVAP Canister -  Disconnect fuel tank vapor tube at fuel vapor tee and plug opening in tee. Turn ignition on, engine off. Close EVAP Canister Vent (CV) solenoid using EVAPCV PID from OUTPUT TEST mode on scan tool. Pressurize EVAP system to 14 in. H2O (3.48 kPa). Using ultrasonic leak detector, check EVAP system from intake manifold to EVAP CV solenoid. If no leak is detected, open EVAP CV solenoid and go to next step. If a leak is detected, repair or install NEW component as necessary. After repair, go to step  10.
  9. Check For Small Leak Between Fuel Tank Vapor Tube & Fuel Tank Filler Pipe -  Transfer plug from fuel vapor tee to fuel tank vapor tube. Pressurize EVAP system to 14 in. H2O (3.48 kPa). Using ultrasonic leak detector, check fuel tank vapor tube to fuel tank for leaks. Check Fuel Tank Pressure (FTP) sensor, fuel tank vapor tube and fuel filler pipe. If a leak is detected, repair or install NEW component as necessary. After repair, go to next step. If no leak is detected, reconnect fuel vapor tube to fuel vapor tee. Go to step  11.
  10. EVAP System Leak Test -  Connect all disconnected connectors and hoses. Perform EVAP System Leak Test. Refer to EVAPORATIVE EMISSIONS SYSTEM LEAK TEST under FUEL EVAPORATIVE SYSTEM under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - B2300, B3000, B4000 & TRIBUTE article. If test result is okay, go to step  12 to verify repair. If test result is not okay, locate leak and repair. After repair, repeat EVAP System Leak Test.
  11. Drive Cycle -  Reconnect all disconnected connectors. Clear DTCs from PCM memory using scan tool generic OBD-II function. Perform Catalyst Monitor Repair Verification Drive Cycle. Refer to MONITOR REPAIR VERIFICATION DRIVE CYCLES  under DRIVE CYCLE PROCEDURES. Retrieve pending code. If same DTC is present, replace PCM. After repair, go to next step. If same DTC is not set, go to next step.
  12. Verify Trouble Shooting Of DTCs Completed -  Perform PCM Quick Test. If any DTC is present, go to applicable procedure for other DTCs. See DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no DTCs are set, trouble shooting is complete.
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