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Home >> Saturn >> 2000 >> LW2 Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics >> Diagnostic Tests >> DTC P0448: EVAP Vent Valve Control Circuit Shorted >> Diagnostic Procedures
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Diagnostic Procedures

  1. Perform On-Board Diagnostic (OBD) system check. See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
  2. Turn ignition on, with engine off. Using scan tool, command EVAP vent solenoid on and off. If solenoid clicks when commanded on and off, problem is intermittent. See DIAGNOSTIC AIDS . If solenoid does not click when commanded on and off, go to next step.
  3. NOTE: A voltage reading of 2-4 volts in this circuit is normal.
  4. Disconnect EVAP vent valve solenoid harness connector. Connect a test light between solenoid harness 2-pin connector terminals. Using scan tool, command EVAP vent solenoid on and off. If test light turns on and off as commanded, replace EVAP vent solenoid. If test light does not turn on and off as commanded, check for short to ground in circuit between vent solenoid and ECM. Repair as necessary. If circuit is okay, replace ECM.