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Service bulletins for the 2021 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.

1649 on file from NHTSA, as of 2026-10-19.

By type

By component

By trouble code

By topic

Only bulletins with component: Equipment and accessories are shown. Show all

Bulletins, newest first
16NA3802020-11-30. Service bulletin. ENGINE AND ENGINE COOLING:EXHAUST SYSTEM:MANIFOLD/HEADER/MUFFLER/TAIL PIPE; EQUIPMENT; EQUIPMENT ADAPTIVE/MOBILITY. This informational bulletin provides a procedure on how to perform a quick test to check if the DPF is the cause of excessive soot from the tailpipe.
16NA3722020-11-30. Service bulletin. EQUIPMENT; ENGINE AND ENGINE COOLING:ENGINE:DIESEL; FUEL SYSTEM, DIESEL. This bulletin provides information on common diesel engine tick noises and how they are considered part of normal operation and no parts should be replaced for these normal operating conditions.
16NA2442020-11-30. Service bulletin. EQUIPMENT; FUEL SYSTEM, DIESEL. This informational bulletin provides information on Diesel Exhaust Fluid (DEF) and the proper use of the DEF system.
PIT5387H2020-11-16. Service bulletin. EQUIPMENT; ELECTRICAL SYSTEM. This Preliminary Information communication provides information to the technician how to repair vehicles that Instrument Panel Cluster, Radio, and Heater-Vent-Air Conditioning display blanks out, Bluetooth phone or Pandora connection dropped, the radio station or volume changes when operating the snow plow. Please advise the customer that engineering is aware of this concern and working on this issue.
PIT5734A2020-11-16. Service bulletin. EQUIPMENT:APPLIANCE:AIR CONDITIONER. This Preliminary information communicates an issue with poor heater performance and advises dealerships to inspect the heater core inlet and outlet hoses for being twisted or kinked.
PIT5736A2020-11-16. Service bulletin. EQUIPMENT:APPLIANCE:AIR CONDITIONER. This Preliminary information communicates how the HVAC setting operates during a remote vehicle start.
PIE05842020-10-26. Service bulletin. EXTERIOR LIGHTING; EQUIPMENT ADAPTIVE/MOBILITY; EQUIPMENT. This engineering information (EI) is requesting information from technicians to provided the engineers listed in regards to No Trailer Lights, No Brake Lights and/or Trailer Tow Receptacle is Loose.
110089005P2020-10-26. Service bulletin. EQUIPMENT:OTHER:OWNERS/SERVICE/OTHER MANUAL. This Warranty Administration bulletin provides information on Dealer Empowerment for Goodwill, Customer Enthusiasm and Policy (U.S. Only).
20NA1572020-10-26. Service bulletin. EQUIPMENT; ELECTRICAL SYSTEM. This bulletin provides information on the Transport Mode On Message Being Displayed in the Driver Information Center (DIC) and/or Battery Light is Flashing and the procedures to turn the Transport Mode message ON and OFF.
18NA3062020-10-26. Service bulletin. EQUIPMENT; STRUCTURE:BODY. This Warranty Administration bulletin provides information for dealers/Service advisors on when and how to submit a Pre-Repair Authorization (PRA) (US dealers only).
PIP5733B2020-09-14. Service bulletin. EQUIPMENT; ENGINE. This Preliminary information communicates Possible Crank no start or extended crank with DTC p12A6 set current or history. Under Investigation
PIP5684B2020-08-10. Service bulletin. ENGINE; ENGINE AND ENGINE COOLING:COOLING SYSTEM; EQUIPMENT. This Preliminary information communicates the use of air leak diagnostic test tool CH-52250 in addition to the information found in the service manual.
090089002R2020-06-01. Service bulletin. EQUIPMENT ADAPTIVE/MOBILITY; EQUIPMENT:OTHER:OWNERS/SERVICE/OTHER MANUAL. This informational bulletin advises the dealers to maintain the vehicle stock on hand by doing a full inspection on the vehicles before sold (prepping) to the customer.

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