When operated in extremely dusty environments, there may be some dust intrusion into the evaporative emission (EVAP) system that can plug the canister and canister vent solenoid on some 2019-2023 Silverado 1500, Sierra 1500; 2022 Silverado 1500 LTD, Sierra 1500 Limited; 2020-2024 Silverado 2500HD/3500HD and Sierra 2500HD/3500HD models. DTCs P0442 (Evaporative Emission System Small Leak Detected), P0446 (EVAP Vent System Performance), P0455 (Evaporative Emission System Large Leak Detected) or P0449 (Evaporative Emission Canister Vent Valve Control Circuit) also may set.
An in-line filter may be installed between the EVAP canister and air inlet to address this condition. Shown is an original EVAP canister vent hose (Fig. 8, bottom) and a modified vent hose with the filter assembly. (Fig. 8, top)
Fig. 8
TIP: The retrofit to add the in-line filter is a customer-pay repair. The filter is meant to be a maintenance item that should be checked periodically to help prevent dust intrusion in the EVAP system.
The filter assembly features three parts, including the in-line filter (Fig. 9, #1), that is installed as part of the EVAP canister vent hose. Refer to Evaporative Emission Canister Vent Hose Replacement (Filler Pipe to Pipe) in the appropriate Service Information.
Fig. 9
After the in-line filter assembly is installed in a new hose section (Fig. 10, #2 and #3), the hose is secured to the pre-filter (Fig. 10, #1) and to a male fitting that connects to the quick connect fitting on the canister vent solenoid jumper line. (Fig. 10, #4)
Fig. 10
With the new hose and in-line filter assembly installed on the EVAP canister vent hose (Fig. 11), secure the new hose at the same locations as the previous line. (Fig. 12)
Fig. 11
Fig. 12
Refer to Bulletin #23-NA-073 for additional information and part numbers.
– Thanks to Kevin Minor
Engineering has confirmed that the installation of the filter will not cause a restriction. It has been flow tested and does not have an impact on the functionality of the EVAP system. The filter is for severe use cases only and, when included as part of a maintenance program, will help prevent repeat EVAP plugging issues due to severe dust intrusion.
Every Gm model since 1995 has had issues with the EVAP vent system plugging up. Its too bad the enginneers who design gm vehicles can’t come up with a vent location that actually works. Adding an aux filter seems like a poor approach. Adding another restriction to the system isn’t going to work. Relocating the vent filter to a less dusty environment is really the only solution.