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DTC P0456: EVAP System Malfunction, Small Leak Detected: Testing

NOTE: Ensure freeze frame data has been recorded. Check for service bulletins and on-line information.
  1. Check for DTCs. If any DTCs are present, repair those DTCs first. If no other DTCs are present, go to next step.
  2. Perform EVAP SYSTEM TEST. See SYSTEM & COMPONENT TESTING - MIATA, MILLENIA, MPV, PROTEGE & 626 article. If system fails, go to next step. If system passes, problem is intermittent. Check purge solenoid valve and CDCV circuit.
  3. Perform WHOLE SYSTEM TEST. See SYSTEM & COMPONENT TESTING - MIATA, MILLENIA, MPV, PROTEGE & 626 article. 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  13 . If system passes, problem is not present at this time. Go to step  14 .
  4. Perform CHARCOAL CANISTER-TO-FUEL TANK TEST. See SYSTEM & COMPONENT TESTING - MIATA, MILLENIA, MPV, PROTEGE & 626 article. If system fails, go to next step. If system passes, go to step  8 .
  5. Remove and inspect fuel tank and all attached components for leaks or damage. If no problems are found, go to next step. If any leaks or damage is found, repair or replace as needed. After repair, go to step  14 .
  6. Inspect rollover valve. See SYSTEM & COMPONENT TESTING - MIATA, MILLENIA, MPV, PROTEGE & 626 article. If rollover valve is okay, go to next step. Replace as needed. Go to step  14 .
  7. Check vent cut valve for leaks. See SYSTEM & COMPONENT TESTING - MIATA, MILLENIA, MPV, PROTEGE & 626 article. Replace filler pipe assembly as needed. If vent cut valve is okay, repair loose damage or misrouted hoses between charcoal canister, vent cut valve and fuel tank. After repair, go to step  14 .
  8. Perform CHARCOAL CANISTER-TO-PURGE SOLENOID TEST. See SYSTEM & COMPONENT TESTING - MIATA, MILLENIA, MPV, PROTEGE & 626 article. If system fails, go to next step. If system passes, go to step  14 .
  9. Remove catch tank in engine compartment. Inspect for leaks, damage or clogging. If catch tank is okay, go to next step. If problem is present, replace as needed. Go to step  14 .
  10. Inspect purge solenoid valve. See SYSTEM & COMPONENT TESTING - MIATA, MILLENIA, MPV, PROTEGE & 626 article. If purge solenoid valve is okay, go to next step. If problem is present, replace as needed. Go to step  14 .
  11. Remove charcoal canister beside fuel tank. Inspect for leaks, damage or clogging. If charcoal canister is okay, go to next step. If problem is present, replace as needed. Go to step  14 .
  12. Inspect Canister Drain Cut Valve (CDCV). See SYSTEM & COMPONENT TESTING - MIATA, MILLENIA, MPV, PROTEGE & 626 article. If CDCV is okay, repair or replace hoses between charcoal canister and CDCV. If CDCV is faulty, replace as needed. After repair, go to step  14 .
  13. Using evap system tester, check for leaks. If problem is found, repair as necessary. If no problem is found or after repair, go to next step.
  14. Turn ignition on. Using scan tool, access PID/DATA MONITOR. Check PID data for BARO V, ECT, IAT and FTL PIDs. See EVAP TEST REQUIREMENTS  . If any data is not within specification, go to next step. If all data is within specification, go to step  17 .
  15. Perform EVAP SYSTEM TEST. See SYSTEM & COMPONENT TESTING - MIATA, MILLENIA, MPV, PROTEGE & 626 article. If system fails, go to next step. If system passes, system is okay. Go to step  21 .
  16. Turn ignition on. Using scan tool, access PID/DATA MONITOR. Check PID data for BARO, ECT, IAT and FTL PIDs. Compare readings with specifications. See EVAP TEST REQUIREMENTS  . If all readings are within specifications, go to next step. If any readings are not within specifications, take action necessary (e.g. cool down engine). Repeat this step.
  17. Erase DTC. See CLEARING CODES in SELF-DIAGNOSTICS - INTRODUCTION - MIATA, MILLENIA, MPV & PROTEGE article. Review Drive Mode 4 procedure. See SELF-DIAGNOSTICS - INTRODUCTION - MIATA, MILLENIA, MPV & PROTEGE article. If Drive Mode 4 cannot be performed, go to next step. If Drive Mode 4 can be performed, go to step  19 .
  18. Perform EVAP SYSTEM TEST. See SYSTEM & COMPONENT TESTING - EXCEPT B2500, B3000 & B4000 article. If system passes, system is okay. Go to step  21 . If system fails, replace PCM, then go to step  21 . PCM is mounted to passenger floor, behind glove box.
  19. Erase DTC. See CLEARING CODES in SELF-DIAGNOSTICS - INTRODUCTION - MIATA, MILLENIA, MPV & PROTEGE article. Conduct Drive Mode No. 4 under DRIVE CYCLE PROCEDURE. See SELF-DIAGNOSTICS - INTRODUCTION - MIATA, MILLENIA, MPV & PROTEGE article. Stop vehicle. Using scan tool, check Drive Mode status. If evap purge system has been monitored, go to next step. If evap purge system has not been monitored, go to step  16 .
  20. Using scan tool, verify TEST #10:23:00 in DIAGNOSTIC MONITORING TEST RESULTS. If test exceeds MAX value, go to next step. If test does not exceed MAX value, replace PCM then go to next step.
  21. Perform after repair procedure. See AFTER REPAIR PROCEDURE  . If no DTC is present, testing is complete. If any DTC is present, go to appropriate test for diagnosis and repair.
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