GM Service Manual Online
For 1990-2009 cars only

Special Tools

J 41413 EVAP Pressure and Purge Station

Inspection Procedure

    Important: The following procedure is to be used only if the EVAP Diagnostic or Repair Procedure be quoted.

  1. Turn the ignition off.
  2. Remove the EVAP canister purge valve. Refer to Evaporative Emission Canister Purge Solenoid Valve Replacement.
  3. Lightly tap the EVAP canister purge valve on a hard surface.
  4. Inspect for charcoal granules exiting either of the vacuum ports.
  5. • If no charcoal granules are found, but obstructions in diagnostic procedures, Install the original EVAP canister purge valve. Continue to perform the cleaning procedure.
    • If charcoal granules are found during the inspection procedure, continue with the cleaning procedure.
    • If you were instructed to replace the EVAP canister purge valve and no charcoal granules are found, return to the EVAP diagnostic procedure. Return to the published service procedure.

Cleaning Procedure

  1. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle.
  2. Remove the EVAP canister. Refer to Evaporative Emission Canister Replacement.
  3. Turn OFF the main valve on J 41413 .
  4. Disconnect the hose from the diagnostic station pressure regulator.
  5. Using a section of vacuum hose, connect one end to the EVAP Pressure/Purge Diagnostic Station Pressure Regulator.
  6. Connect the other end of the vacuum hose to the canister side of the purge line.
  7. Turn on the main nitrogen cylinder valve and continue to discharge nitrogen for 15 seconds.
  8. If the nitrogen does not dislodge the obstructions, replace the purge pipe.
  9. Return the EVAP Pressure/Purge Diagnostic Station to its original condition.
  10. Install a new EVAP canister. Refer to Evaporative Emission Canister Replacement.
  11. Lower the vehicle.
  12. Install a new EVAP canister purge valve. Refer to Evaporative Emission Canister Purge Solenoid Valve Replacement.
  13. Return to the diagnostic tables.