I haven't seen this TSB before. If anyone can post the link to this bulletin it would be appreciated.
General Motors is addressing an issue that may cause check engine lights on 2020/2021 Diesel Silverado and Sierra pickups. Both 3.0L and 6.6L Diesel Duramax engines could have an error related to the emission and/or exhaust fluid systems.
Technical Service Bulletin: #21-NA-07
Release Date: 1/20/2021
General Motors is addressing an issue that may cause check engine lights on 2020/2021 Diesel Silverado and Sierra pickups. Both 3.0L and 6.6L Diesel Duramax engines could have an error related to the emission and/or exhaust fluid systems.
Technical Service Bulletin: #21-NA-07
Release Date: 1/20/2021