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Home >> Mazda >> 2003 >> MX-5 Miata Base, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics >> Diagnostic Tests >> DTC P0442: EVAP Control System Small Leak Detected >> Diagnostic Procedure
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Diagnostic Procedure

  1. Verify Related Repair Information Availability -  Turn ignition off. Connect scan tool to DLC-2. See Figure. Turn ignition on. 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  18.
  2. Inspect For Other DTCs -  Leave ignition on. Monitor for other DTCs. If malfunction code recordedis P0442, go to next step. If malfunction code(s) recordedare P0443 and/or P1449, follow appropriate DTC diagnostic procedure. See DIAGNOSTIC TROUBLE CODE DEFINITIONS .
    NOTE: When fuel filler caps other than OEM caps are attached, it is considered malfunction.
  3. Inspect Fuel Filler Cap -  Turn ignition off. Inspect fuel filler cap for installation (loose) or damage. If fuel filler cap is properly install and no damage is found, go to next step. If fuel filler cap is faulty, either reinstall properly or replace fuel filler cap. After repair, go to step  18.
  4. Inspect Whole System Of EVAP System -  Perform Whole System Inspection of EVAP system, see FUEL EVAPORATIVE SYSTEM (MIATA & MPV) under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If scan tool value holds for a minimum of 2 minutes, no leaks were detected in EVAP control system. Go to step  14. If scan tool does not hold value for a minimum of 2 minutes and an evaporative emission tester is available, go to step  13. If tester is not available, go to next step.
  5. Inspect Leakage From Charcoal Canister To Fuel Tank -  Inspect for leak from charcoal canister to fuel tank. See EVAPORATIVE SYSTEM LEAK INSPECTION USING LEAK TESTER under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If scan tool does not drop to less than specified and hold value for a minimum of 2 minutes, go to next step. If scan tool value drops to less than specified and holds for a minimum of 2 minutes, go to step  8.
  6. Inspect Attached Accessories On Fuel Tank -  Remove fuel tank and visually inspect for damage, insufficient sealing, or poorly attached accessories on fuel tank, such as fuel gauge. If fuel tank and accessories are okay, go to next step. If fuel tank accessories are faulty, repair or replace fuel tank or sealing as necessary. After repair, go to step  14.
    NOTE: Rollover valve is an integral part of fuel tank. If rollover valve is faulty, replace fuel tank.
  7. Inspect Rollover Valve -  With fuel tank removed, inspect rollover valves. See FUEL EVAPORATIVE SYSTEM (MIATA & MPV) under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If rollover valve is okay, inspect hoses from charcoal canister to fuel tank for detached, incorrectly installed or cracked, repair or replace hoses if necessary. After repair, go to step  14. If rollover valve is faulty, replace rollover valve. After repair, go to step  14.
  8. Inspect Leakage From Charcoal Canister To Purge Solenoid Valve -  Inspect leak from charcoal canister to purge solenoid valve. If vacuum drops to less than specified reading and holds for a minimum of 2 minutes, go to step  14. If vacuum does not drop to less than specified reading and hold for a minimum of 2 minutes, go to next step.
  9. Inspect Catch Tank -  Remove catch tank. Plug one port, using vacuum pump apply vacuum at other port. Inspect for plugging, damage or pinhole leaks. If catch tank is okay, go to next step. If catch tank is faulty, replace catch tank. After repair, go to step  14.
  10. Inspect Purge Solenoid Valve -  Remove purge solenoid valve and perform inspection. See FUEL EVAPORATIVE SYSTEM (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  14.
  11. Inspect Charcoal Canister -  Remove charcoal canister. Inspect for plugging, damage or pinhole leaks. See FUEL EVAPORATIVE SYSTEM (MIATA & MPV) under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If charcoal canister is okay, go to next step. If charcoal canister is faulty, replace charcoal canister. After repair, go to step  14.
  12. Inspect CDCV -  Remove CDCV and perform inspection. See FUEL EVAPORATIVE SYSTEM (MIATA & MPV) under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If CDCV is okay, inspect hoses from charcoal canister to CDCV for being detached, incorrect installation or cracking. Repair or replace if necessary. After repair, go to step  14. If CDCV is faulty, replace CDCV. After repair, go to step  14.
  13. Inspect Leakage Of EVAP Control System -  Inspect EVAP control system for leaks using evaporative emission tester. See FUEL-FILLER CAP INSPECTION under FUEL EVAPORATIVE SYSTEM (MIATA & MPV) under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If component is okay, go to next step. If component is faulty, replace component. After repair, go to next step.
  14. Verify EVAP System Repaired -  Return vehicle to original condition. Implement Evaporative Emission System Tester Self Test and Leak Inspection, even if vehicle is not in test condition. See EVAPORATIVE SYSTEM LEAK INSPECTION USING LEAK TESTER under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article.If EVAP system small leak test is faulty, go to next step. If EVAP system small leak test is okay, go to step  18.
  15. Decide On After Repair Procedure According To Repair Shop Condition -  Using scan tool, clear DTCs from PCM memory. See CLEARING DIAGNOSTIC TROUBLE CODES  under SELF-DIAGNOSTIC SYSTEM. Check if repair shop conditions are appropriate to perform Drive Mode 4. If shop conditions are not okay, go to next step. If shop conditions are okay, go to step  17.
  16. Verify EVAP System Repaired By EVAP System Test -  With no DTCs stored in PCM memory, implement Evaporative Emission System Tester Self Test and Leak Inspection again. See EVAPORATIVE SYSTEM LEAK INSPECTION USING LEAK TESTER under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article.If system test result is not okay, replace PCM. After repair, go to step  18. If system test result is okay, go to step  18.
  17. Monitor EVAP System By Drive Mode 4 -  Run EVAP System Repair Verification Drive Mode 4. See MODE 4 - EVAP SYSTEM REPAIR VERIFICATION DRIVE MODE  under DRIVE MODES. Stop vehicle. Using scan tool, access ON BOARD SYSTEM READINESS TEST to inspect Drive Mode completion status. If EVAPORATIVE PURGE SYSTEM has been monitored, go to next step. If EVAPORATIVE PURGE SYSTEM has not been monitored, go back to step  15.
  18. Verify EVAP System Repaired -  Return vehicle to original condition. Using scan tool, clear DTCs from PCM memory. See CLEARING DIAGNOSTIC TROUBLE CODES  under SELF-DIAGNOSTIC SYSTEM. Access DIAGNOSTIC MONITORING TEST RESULTS of generic OBD-II functions and verify TEST ID 10:21:00 value. If test result is less than maximum value, go to next step. If test result is not less than maximum value, 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.
  19. 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, go to applicable test and repair.
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