Tools Required

J 41413 EVAP Pressure/Purge Diagnostic Station

Whenever the DTC diagnostics lead to a no trouble found or a purge solenoid replacement, proceed with the following charcoal canister diagnostics.

Notice: Use the EVAP Pressure/Purge Diagnostic Station J 41413 in order to provide a clean, dry, low pressure gas source. Do not substitute any other pressurized gas source. Damage may result to the EVAP system.

The J 41413 is required to provide a clean, dry, low pressure gas source. Do not substitute any other pressurized gas source or damage to the EVAP system may result.

1. Turn the ignition OFF.
2. Remove the EVAP canister purge valve from the vehicle.
3. Lightly tap the EVAP canister purge valve on a clean work area.
4. Look for carbon particles existing from either of the vacuum ports.
5. If no carbon release is evident, reinstall the components. Continue with the published service manual DTC procedures.
6. If carbon is being released from either component, continue with this service procedure.
7. Remove the charcoal canister from the vehicle.
8. Turn off the main cylinder valve (1) on the EVAP purge/pressure diagnostic station J 41413.
9. Disconnect the black hose (4) that connects the nitrogen cylinder to the cart J 41413 at the pressure regulator (5).
10. Using a section of the vacuum hose, connect one end onto the open fitting of the J 41413 pressure regulator (5).
11. Connect the other end of the vacuum line side of the EVAP purge line at the vehicle.
12. Turn on the main nitrogen cylinder valve (1).
13. Continue to blow any debris from the purge line for 15 seconds.
14. Return the J 41413 to its original condition by re-installing the black hose (4) disconnected in step 9.
15. Replace the EVAP purge valve and the charcoal canister with the new components.
16. Proceed with the published service manual diagnostics for the manifold vacuum vehicles (4.3L).

1. Connect a scan tool and display the data parameter EVAP Canister Purge Valve.
2. Start the engine and allow the engine to reach the operating temperature.
3. Open the throttle until the engine speed reaches 2000 RPM.
4. If the EVAP Canister purge valve changes its state, go to step 6.
5. If the EVAP Canister Purge Valve does not change state, repair the low source vacuum condition by performing a complete throttle body service including a cleaning of the purge port(s). Go to step 1.
6. If the EVAP Canister Purge Valve does change state, proceed with the published service manual diagnostics.

1. Connect the EVAP diagnostic cart J 41413 (1) to the vehicle EVAP service port. Turn the four position switch to Purge.
2. Start the engine. Allow the engine to reach the operating temperature.
3. Open the throttle until the engine speed reaches 2000 RPM.
4. Note the H2O vacuum gauge (6) on the EVAP cart. The vacuum should read greater than 15 in H2O.
5. If the vacuum is less than 15 in H2O, perform a complete throttle body service including a cleaning of the purge port(s) as outlined in the service manual. Go to step 1.
6. If the vacuum is greater than 15 in H2O, continue with the published service manual diagnostics.