Diagnostic Procedures

WARNING: This page is about a different car, the 2002 Mazda B4000, 2002 Mazda B3000, and 2002 Mazda B2300. However, it is still accessible from the selected car via links, so may be relevant.

If QUICK TEST was not performed, go to QUICK TEST under SELF-DIAGNOSTIC SYSTEM. If QUICK TEST was performed:
- For DTC P0455, go to step 2 .
- For DTC P1443, go to step 3 .

Visually Check For Large EVAP System Leak

Verify fuel cap is installed. DO NOT tighten cap or check for correct installation at this time. Verify both input port vacuum hose and EVAP return hose are attached to EVAP canister purge valve. Verify Canister Vent (CV) solenoid is properly attached to EVAP canister. Visually inspect fuel vapor hoses for disconnected, cracked or loose connections to intake manifold and the following locations:
- EVAP canister purge valve.
- EVAP canister.
- Fuel vapor vent valve assembly.
Check for damage to fuel filler pipe and fuel tank. If a problem is found, repair or install a new component as necessary. Go to step 7 . If a problem is not found, go to next step.

Check For EVAP System Leaks

Disconnect EVAP return hose from intake manifold and plug EVAP return hose. Connect EVAP System Leak Tester to EVAP test port. Perform EVAP System Leak Test. If pressure stays above 8 in. H2O (1.99 kPa), go to next step. If pressure does not stay above 8 in. H2O (1.99 kPa), verify fuel filler cap is properly installed. Repair or install new components as necessary. Go to step 7 .

Check For Blockage Between EVAP Canister Purge Valve & Fuel Vapor Tee

With KOEO, using scan tool, select Diagnostic Data Link. Select PCM. Select Active Command Modes. Select Output Test Mode. Close EVAP CV solenoid using EVAPCV PID. Pressurize EVAP system to 14 in. H2O (3.48 kPa). Press STOP (#4) to open CV solenoid. Observe pressure. If pressure drops immediately, go to next step. If pressure does not drop immediately, install a new vapor line between EVAP canister purge valve and fuel vapor tee. Go to step 8 .

Check For Blockage Between Fuel Filler Pipe & Fuel Vapor Tee

Connect EVAP System Leak Tester to fuel filler pipe. Using scan tool, select Diagnostic Data Link. Select PCM. Select Active Command Modes. Select Output Test Mode. Close EVAP CV solenoid using EVAPCV PID. Pressurize EVAP system to 14 in. H2O (3.48 kPa). Press STOP (#4) to open CV solenoid. Observe pressure. If pressure drops immediately, go to next step. If pressure does not drop immediately, install NEW fuel tank vapor line(s). Repeat this test step to verify repair. Go to step 8 .

Check For Failed EVAP Canister Purge Valve Or Fuel Tank Pressure Sensor

If both DTC P0455 and P1443 were set at step 1 , install a NEW EVAP canister purge valve. Go to next step. If both DTC P0455 and P1443 were not set at step 1 , install a NEW fuel tank pressure sensor. Go to next step.

EVAP System Leak Test

Connect all disconnected connectors and hoses. Perform EVAP System Leak Test. If EVAP System Leak Test passes, go to step 9 to verify repair. If EVAP System Leak Test does not pass, locate and repair leak. Repeat this step.

Drive Cycle

Reconnect all connectors. Using scan tool, clear DTC memory. Perform EVAP RUNNING LOSS SYSTEM REPAIR VERIFICATION DRIVE CYCLE in MONITOR REPAIR VERIFICATION DRIVE CYCLES under DRIVE CYCLE PROCEDURES. Using scan tool, retrieve DTCs. If same DTC is not present, go to next step. If same DTC is present, replace faulty PCM. Go to next step.

Verify Trouble Shooting Of DTCs Completed

Perform QUICK TEST under SELF-DIAGNOSTIC SYSTEM. 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.