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Home >> Mazda >> 1998 >> 626 ES, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes - Testing >> Diagnostic Trouble Codes >> DTC P1450: EVAP Control System >> Condition
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DTC P1450: EVAP Control System: Condition

DTC indicates that PCM has detected EVAP control system has excessive fuel tank vacuum. Possible causes are:

  1. Check Purge Solenoid Valve

    Remove vacuum hose from intake manifold input on purge solenoid valve. Apply 8.4 in. Hg of vacuum to open port on solenoid part of valve. If vacuum is rapidly released, go to next step. If vacuum is not rapidly released, replace purge solenoid valve. Repeat QUICK TEST. See TESTS W/CODES - INTRODUCTION article.
  2. Check Purge Solenoid Valve Resistance

    Turn ignition off. Measure resistance between solenoid terminals. If resistance is 30-36 ohms, go to next step. If resistance is not 30-36 ohms, replace purge solenoid valve. Clear PCM Memory and repeat QUICK TEST. See TESTS W/CODES - INTRODUCTION article.
  3. Check Purge Solenoid Valve Circuit Continuity

    Turn ignition off. Disconnect PCM wiring harness connector. Inspect pins for damage and repair as necessary. Install Breakout Box (014-00950), leaving PCM disconnected. Measure resistance between test pin No. 67 and test pins No. 24 and 103. If resistance is greater than 10 k/ohms, go to next step. If resistance is 10 k/ohms or less, repair short to ground in circuit. Clear PCM memory and repeat QUICK TEST. See TESTS W/CODES - INTRODUCTION article.
  4. Check FTP Sensor VPWR Circuit Continuity

    Turn ignition off. Disconnect FTP VPWR terminal on FTP sensor harness connector. If resistance is less than 5 ohms, replace FTP sensor and repeat QUICK TEST. See TESTS W/CODES - INTRODUCTION article. If resistance is 5 ohms or greater, repair open VPWR circuit and repeat QUICK TEST.