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Home >> GMC >> 2006 >> Envoy 4.2 S, 4WD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - 4.2L - DTC P0420 To P1682 >> DTC P0455 >> Circuit/System Testing

Circuit/System Testing

IMPORTANT:
  • Larger volume fuel tanks and/or those with lower fuel levels may require several minutes for the floating indicator to stabilize.
  • Refer to the J 41413-200  operation manual for detailed instructions. See Special Tools .
  1. Using the GE-41415-50  , connect the J 41413-200  to the vehicle filler neck. See Special Tools .
  2. Use the flow meter on the J 41413-200  , calibrated to 0. See Special Tools .51 mm (0.020 in) to determine that there is no leak in the EVAP system.
    • If a leak is detected use the J 41413-200  to apply smoke to the EVAP system at the service port or the filler neck until the leak is located. See Special Tools .
  3. Start the engine with the J 41413-200  connected to the fuel filler neck. See Special Tools .
  4. Allow the engine to idle.
  5. Use the Purge/Seal function to seal the system with a scan tool.
  6. Command the EVAP canister purge solenoid valve to 20 percent.
  7. The vacuum/pressure gage on the J 41413-200  and the FTP parameter on the scan tool should both show vacuum. See Special Tools .
    • If the vacuum/pressure gage on the J 41413-200  does not show vacuum, check for a restricted purge path. See Special Tools .
  8. Vacuum should increase on the gage of the J 41413-200  and scan tool until it reaches approximately 16 inches H2O, or until the vacuum reaches the abort limit on the scan tool. See Special Tools .
    • If the difference between the FTP parameter on a scan tool and the vacuum/pressure gage on the J 41413-200  was more than 1 inch, replace the FTP sensor. See Special Tools .
    • If the maximum Fuel Tank Pressure Sensor parameter on a scan tool display was less than 3.2 volts, replace the FTP sensor.
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