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Service bulletins for the 2020 GMC Sierra

A bulletin is a manufacturer's communication to its dealers, as NHTSA indexes it. The summary is NHTSA's. The document is the manufacturer's: read it at NHTSA. A bulletin is not a recall, and listing a model year does not mean every vehicle of it is concerned.

1990 on file from NHTSA, as of 2026-10-19.

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Only bulletins with component: Transmission control module are shown. Show all

Bulletins, newest first
PIP5621C2022-10-17. Service bulletin. POWER TRAIN:AUTOMATIC TRANSMISSION:CONTROL MODULE (TCM/PCM/TECM); POWER TRAIN. This Preliminary information communicates to the dealer technician that TAC recommends the utilization of the GDS2 software to aid in diagnosing automatic transmission concerns. TAC is requesting the GDS2 session logs be sent in before the dealer contacts TAC.
N212354170-022022-04-26. Service bulletin. POWER TRAIN:AUTOMATIC TRANSMISSION:CONTROL MODULE (TCM/PCM/TECM); ELECTRICAL SYSTEM; ENGINE AND ENGINE COOLING:ENGINE:DIESEL. Emission Recall - General Motors has decided to conduct a Voluntary Emissions Recall to improve the operation of the regeneration cycle on certain 2020 Chevrolet Silverado and GMC Sierra vehicles with a 6.6L diesel engine. The recall will address that currently under certain operating conditions, higher than necessary temperatures may be used to clean the Diesel Particulate Filter (DPF) during the regeneration cycle. Dealers are to reprogram the Engine Control Module (ECM) and Transmission Control Module (TCM).
19NA2282020-08-10. Service bulletin. POWER TRAIN:AUTOMATIC TRANSMISSION:CONTROL MODULE (TCM/PCM/TECM); ELECTRICAL SYSTEM. This technical provides a procedure to locate, disconnect and re-connect the TCM electrical connector if found the cause of the customers concerns.

The summaries are NHTSA's. Each bulletin's page links NHTSA's copy of the manufacturer's document.