General Motors has issued a service update to address an issue related to the transmission control module (TCM) in certain examples of the 2020 model year Chevy Silverado HD and GMC Sierra HD pickup trucks.
The problem: affected vehicles may have left the factory without the proper transmission control module calibrations.
The hazards: GM did not say what problems an improperly calibrated TCM may lead to. However, the TCM is an important part of the transmission’s functionality and an improperly calibrated TCM could eventually lead to problems or complications with the vehicle’s transmission and overall running operation.
The fix: dealers will be instructed to reprogram the TCM in affected vehicles. These repairs will be performed at no cost to the vehicle owner. No parts will be required to perform this repair, as it can be remedied via software update.
Affected components: transmission control module (TCM).
Owners should: owners can wait for GM to reach out to them to make an appointment with their dealership. This service update is for vehicles in dealership inventory and customer vehicles that return to the dealership for any reason in the future. Dealers and owners can reach out to Chevrolet or GMC directly using the contact information included below with any questions or concerns they may have. The service update was released in August 2021 and will expire at the end of the truck’s New Vehicle Limited Warranty Period.
- GM Service Update number: N212332210
- Chevrolet Customer Service: 1-800-222-1020
- GMC Customer Service: 1-800-462-8782