EVAP Canister Inspection

Tools Required 

J 23738-A  Hand Vacuum Pump

Fig 1: EVAP Canister Inspection
Courtesy of GENERAL MOTORS CORP.
1. Remove the EVAP canister. Refer to Evaporative Emission (EVAP) Canister Replacement .
2. Visually inspect the EVAP canister, especially at the arrows, for any cracks or damage.
Fig 2: Checking Drain Hose Pressure (Blocking Purge Port)
Courtesy of GENERAL MOTORS CORP.
CAUTION: Refer to Fuel Vapors in Evaporative Emission (EVAP) Components Caution in Cautions and Notices.
3. Plug the vent port (4). The vent port will remain plugged for all the tests.
4. Block the purge port (3) closed.
5. Blow air with a pressure of 1.7 kPa (0.5 in Hg/0.25 psi) into the EVAP vapor port (2).
6. Verify that air flows out of drain hose (1).
Fig 3: Checking Air Inlet Port Pressure (Blocking Purge Port & Drain Hose)
Courtesy of GENERAL MOTORS CORP.
7. Block the purge port (3) and the drain hose (1) closed.
8. Blow air with a pressure of 1.7 kPa (0.5 in Hg/0.25 psi) into the EVAP vapor port (4).
9. Verify that air does not flow out of the air inlet port (2).
Fig 4: EVAP Canister Air Inlet Port Vacuum Test
Courtesy of GENERAL MOTORS CORP.
10. Block the air inlet port (2) closed.
11. Connect the J 23738-A  or an equivalent hand vacuum pump to the purge port (1).
12. Apply a vacuum of 3.5 kPa (1.0 in Hg/0.5 psi) to purge port (1) with the hand vacuum pump.
13. Verify that the vacuum holds while the air inlet port (2) is closed.
14. Open the air inlet port (2) and verify that the vacuum is released.
Fig 5: EVAP Canister Purge Port Vacuum Test
Courtesy of GENERAL MOTORS CORP.
15. Block the air inlet port (1) closed.
16. Connect the J 23738-A  or an equivalent hand vacuum pump to the EVAP vapor port (3).
17. Apply a vacuum of 3.5 kPa (1.0 in Hg/0.5 psi) to the EVAP port (3) with the hand vacuum pump.
18. Verify that there is vacuum pressure at the purge port (2).
19. Replace the EVAP canister if the canister failed any of the inspections or tests. Refer to Evaporative Emission (EVAP) Canister Replacement .