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DTC P1450: EVAP System Malfunction, Excessive Vacuum: Testing

NOTE: Ensure freeze frame data has been recorded. Check for service bulletins and on-line information.
  1. Check DTCs. If DTCs P0443 or P1449 are present, repair those DTCs first. If DTCs listed are not present, go to next step.
  2. Using scan tool, run IGNITION ON TEST in SIMULATION TEST. Turn Canister Drain Cut Valve (CDCV) from OFF to ON. CDCV and Tank Pressure Control Valve (TPCV) should be heard operating. If system operates correctly, go to next step. If system does not operate correctly, repair wiring and/or replace CDCV. After repair, go to step  7 .
  3. Disconnect intake manifold vacuum hose at purge solenoid valve. Apply vacuum at purge solenoid valve fitting. If vacuum holds for at least a few seconds, reconnect hose and go to next step. If vacuum does not hold, inspect purge solenoid valve. See SYSTEM & COMPONENT TESTING - MIATA, MILLENIA, MPV, PROTEGE & 626 article. Repair or replace as needed. After repair, go to step  7 .
  4. Remove charcoal canister beside fuel tank. Inspect for damage or clogging. If charcoal canister is okay, go to next step. If canister is faulty, replace canister. After repair, go to step  7 .
  5. Inspect Fuel Tank Pressure (FTP) sensor. See SYSTEM & COMPONENT TESTING - MIATA, MILLENIA, MPV, PROTEGE & 626 article. If FTP sensor is okay, go to next step. If sensor is faulty, replace FTP sensor. After repair, go to step  7 .
  6. Inspect EVAP air filter, located at CDCV, for clogging. See SYSTEM & COMPONENT TESTING - MIATA, MILLENIA, MPV, PROTEGE & 626 article. If EVAP air filter is okay, check for clogging between charcoal canister and CDCV. Check for clogging in drain passage. If problem is found, repair as necessary. After repair, go to next step.
  7. 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.
  8. 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  7 .
  9. Reconnect all components. Turn ignition off, then on. Recheck DTCs. If DTC P1450 is present, replace PCM and go to next step. PCM is mounted to passenger floor, behind glove box. If DTC P1450 is not present, go to next step.
  10. 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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