Some units of the 2021 Corvette Stingray may require a Transmission Control Module reprogramming.
The error in the module software could result in the active permanent status of a Diagnostic Trouble Code (DTC).
To address this issue, General Motors has released a new service update.

The new GM Service Update is tagged as N212350930, and was released in February 2024.
The service update only affects units of the C8 Corvette Stingray produced for the 2021 model year.
GM did not specify the number of units potentially affected by this issue.

According to the service update, certain 2021 model-year Chevy Corvette vehicles may incorrectly read an active permanent status for Transmission Control Module DTC P2781 (Downshift Switch Circuit High).

This could result in an automatic failure during emissions testing in jurisdictions that check the permanent's status of engine codes as part of the emissions testing protocol.

In order to address this issue, GM is instructing dealers to reprogram the Transmission Control Module with updated software through a dealer repair.
It’s also possible that vehicles involved in this service update can be reprogrammed using an over-the-air software update.