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Home >> Mazda >> 2001 >> MX-5 Miata Base, Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics >> Diagnostic Tests >> DTC P0442: EVAP Control System, Small Leak Detected >> Diagnosis & Repair Procedure
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Diagnosis & Repair Procedure

  1. Ensure FREEZE FRAME DATA has been recorded. Check for related service bulletins. Repair as necessary and go to next step.
  2. Turn ignition off and on. 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. Connect scan tool. Perform evaporative emission control system inspection. See SYSTEM & COMPONENT TESTING - MIATA, MILLENIA, MPV, PROTEGE & 626 article. If system fails test, go to next step. If system passes (no leaks), problem is intermittent. See TROUBLE SHOOTING - NO CODES article. Check purge solenoid valve and CDCV wiring circuit. Repair or replace as necessary.
  4. Inspect fuel filler cap. Ensure fuel filler cap is secure and not leaking. If fuel filler cap is not leaking, ensure fuel filler cap is original equipment. Replace as necessary and go to step  18. If fuel filler cap is okay, go to next step.
  5. Using scan tool, perform complete EVAP system inspection. Follow scan tool manufacturer's instructions. If system passes (holds vacuum for 2 minutes or more), go to step  18. If system fails and EVAP system tester is not available, go to next step. If system fails, and EVAP system tester is available, go to step  17.
  6. Using scan tool, perform EVAP control system inspection from charcoal canister to fuel tank. Follow scan tool manufacturer's instructions. If system leaks, go to next step. If system passes (holds vacuum for 2 minutes or more), go to step  12.
  7. Remove and inspect fuel tank and fuel gauge sending unit for leakage or damage. If fuel tank and fuel gauge sending unit are okay, go to next step. If problem is found, repair or replace as necessary and go to step  18.
    8. NOTE: Rollover valve is an integral part of fuel tank. If rollover valve is faulty, replace fuel tank.
  8. Inspect rollover valve following way: Disconnect negative battery cable. Release fuel system pressure. See FUEL SYSTEM PRESSURE RELEASE in REMOVAL, OVERHAUL & INSTALLATION article. Remove rear package trim. Remove fuel pump access cover. Disconnect fuel hoses and electrical connector. See FUEL LINE CONNECTORS in REMOVAL, OVERHAUL & INSTALLATION article. Go to next step.
  9. Remove pre-silencer pipe assembly. Remove drive shaft. Disconnect emergency brake cable from brake lever to release brake cables from rear calipers. Disconnect rear brake lines from rear calipers. Remove rear suspension assembly. Remove lower fuel tank covers. Remove fuel tank and place it right-side up on a level surface. Plug fuel pump supply line and return line ports at fuel pump. Plug port "A". See Fig 1. Apply low-pressure air to port "B" and ensure there is airflow from port "C". Go to next step.
  10. If airflow is not preset, rollover valve is faulty, replace fuel tank. If airflow is present, plug port "C" and unplug port "A". Apply low-pressure air to port "B" and ensure there is airflow from port "A". If airflow is not preset, rollover valve is faulty, replace fuel tank. If airflow is present, unplug port "C" and turn fuel tank upside-down. Apply low-pressure air to port "B" and ensure there is airflow from ports "A" and "C". Go to next step.
  11. If airflow is preset, rollover valve is faulty, replace fuel tank and go to step  18. If rollover valve is okay, repair lines between charcoal canister and fuel tank and go to step  18.
  12. Connect scan tool. Perform evaporative emission control system inspection for charcoal canister to purge solenoid valve. Follow scan tool manufacturer's instructions. If system leaks, go to next step. If system passes (holds vacuum for 2 minutes or more), go to step  18.
  13. Remove catch tank and check catch tank for leaks and plugging. Catch tank is located at right side of engine compartment, next to windshield fluid reservoir. If catch tank is okay, go to next step. If catch tank is plugged or leaking, repair or replace as necessary and go to step  18.
  14. Remove purge solenoid valve and check purge solenoid valve for leaks and damage. Purge solenoid valve is located above catch tank, at right side of engine compartment, next to windshield fluid reservoir. If purge solenoid valve is okay, go to next step. If purge solenoid valve is damaged or leaking, repair or replace as necessary and go to step  18.
  15. Remove charcoal canister located beside fuel tank. Inspect for damage or leaks. If charcoal canister is okay, go to next step. If charcoal canister is not okay, replace as necessary and go to step  18.
  16. Remove Canister Drain Cut Valve (CDCV) and check CDCV for leaks and damage. CDCV is located next to charcoal canister. Repair or replace as necessary and go to step  18. If CDCV is okay, check for cracked, disconnected or improperly routed vacuum hoses between CDCV and charcoal canister and go to step  18.
  17. Using fuel evaporation test equipment, check fuel cap for leaks. Replace fuel cap as necessary and go to next step. If no leaks are found, go to next step.
  18. Turn ignition on. Ensure fuel tank is 1/4-3/4 full. Using scan tool, monitor PID data for BARO, ECT, IAT and FTL V PID data should read BARO is 21.3 in. Hg or more, ECT is 14-90.5° F (-10-32.5°C), IAT is 14-140°F (-10-60°C) and FTL V is .24-2.0 volts. If any signals are not within specification, go to next step. If all signals are within specification, go to step  21.
  19. Connect scan tool. Perform evaporative emission control system inspection. Follow scan tool manufacturer's instructions. If system fails small leak test, go to next step. If system passes test (holds vacuum), system is okay and go to step  25.
  20. Turn ignition on. Ensure fuel tank is 1/4-3/4 full. Using scan tool, monitor PID data for BARO, ECT, IAT and FTL V PID data should read BARO is 21.3 in. Hg or more, ECT is 14-90.5° F (-10-32.5°C), IAT is 14-140°F (-10-60°C) and FTL V is .24-2.0 volts. If any signals are not within specification, allow engine to cool down and repeat this step. If all signals are within specification, go to next step.
  21. Clear DTCs. See CLEARING DIAGNOSTIC TROUBLE CODES  under SELF-DIAGNOSTIC SYSTEM. Review conditions necessary to perform EVAP monitor repair verification drive mode. See DRIVE MODES  under SELF-DIAGNOSTIC SYSTEM. If EVAP monitor repair verification drive mode is possible, go to step  23. If EVAP monitor repair verification drive mode is not possible, go to next step.
  22. Perform evaporative emission control system inspection. See SYSTEM & COMPONENT TESTING - MIATA, MILLENIA, MPV, PROTEGE & 626 article. If system passes test, go to step  25. If system fails test, replace PCM and go to step  25.
  23. Perform EVAP monitor repair verification drive mode. See DRIVE MODES  under SELF-DIAGNOSTIC SYSTEM. Stop vehicle and 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 step  20.
  24. Using scan tool, verify TEST #10:21:00 in DIAGNOSTIC MONITORING TEST RESULTS. If test is less than MAX value, go to next step. If test result is at MAX value or more, replace PCM and go to next step.
  25. Cycle ignition from off to on. Check for DTCs. See RETRIEVING DIAGNOSTIC TROUBLE CODES  under SELF-DIAGNOSTIC SYSTEM. If any other DTC is present, go to appropriate test.
Fig 1: Testing Rollover Valve
G00032524Courtesy of MAZDA MOTORS CORP.
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