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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

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Only bulletins with component: Heating and air conditioning are shown. Show all

Bulletins, newest first
PIT5734G2024-02-12. Service bulletin. EQUIPMENT:OTHER:OWNERS/SERVICE/OTHER MANUAL; VISIBILITY:DEFROSTER/DEFOGGER/HVAC SYSTEM. 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.
PIT5099G2023-12-26. Service bulletin. VISIBILITY:DEFROSTER/DEFOGGER/HVAC SYSTEM. This Preliminary Information communication provides information to the technician about vehicles that the Heater-Vent-Air Conditioning blows warm air. Before calling General Motors Technical Assistance Center technician will need to have high and low pressures, outside temperature, humidity, and vent temperature.
PIT5736C2023-12-18. Service bulletin. VISIBILITY:DEFROSTER/DEFOGGER/HVAC SYSTEM. This Preliminary information communicates how the HVAC setting operates during a remote vehicle start.
PIT5734F2023-08-21. Service bulletin. VISIBILITY:DEFROSTER/DEFOGGER/HVAC SYSTEM. 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.
PIT5767A2023-02-13. Service bulletin. VISIBILITY:DEFROSTER/DEFOGGER/HVAC SYSTEM:CONDENSOR/EVAPORATOR; VISIBILITY:DEFROSTER/DEFOGGER/HVAC SYSTEM. This Preliminary information communicates an issue with poor a/c performance and to replace the a/c condenser.
PIT5868B2023-02-13. Service bulletin. VISIBILITY:DEFROSTER/DEFOGGER/HVAC SYSTEM. This Preliminary information communicates an issues will low or poor heater performance on the drivers side. Dealers are to inspect the HVAC temperature door linkage and if ok replace the heater core.
PIP5540J2023-01-30. Service bulletin. VISIBILITY:DEFROSTER/DEFOGGER/HVAC SYSTEM:REAR WINDOW:ELECTRICAL HEATING ELEMENT. This Preliminary information communicates to the technician the need to inspect the induction system for potential icing issues in very cold ambient temperatures. To allow the ice to melt so that it can be drained from the related components. That any of the listed DTC's may set with or without poor engine performance.
N2223750002022-10-03. Service bulletin. VISIBILITY:DEFROSTER/DEFOGGER/HVAC SYSTEM. In certain vehicles, equipped with a manual HVAC system (RPO: C4P), the K33 HVAC Control Module may not properly enable the heater auxiliary coolant pump to maintain cabin heater temperature during engine auto stop events. Reprogram the K33 HVAC Control Module with updated software.
PIT5099F2022-07-25. Service bulletin. VISIBILITY:DEFROSTER/DEFOGGER/HVAC SYSTEM. This Preliminary Information communication provides information to the technician about vehicles that the Heater-Vent-Air Conditioning blows warm air. Before calling General Motors Technical Assistance Center technician will need to have high and low pressures, outside temperature, humidity, and vent temperature.
12-01-37-001F2022-07-12. Service bulletin. EQUIPMENT; ENGINE AND ENGINE COOLING; VISIBILITY:DEFROSTER/DEFOGGER/HVAC SYSTEM. This service bulletin provides information to dealership personnel on a new refrigerant (R1234yf) for A/C service.
21-NA-0972022-07-01. Service bulletin. VISIBILITY:DEFROSTER/DEFOGGER/HVAC SYSTEM. This technical bulletin provides a procedure to install a pice of foam between the heater core pipes to correct the customers concern.
PIT5734E2022-06-13. Service bulletin. VISIBILITY:DEFROSTER/DEFOGGER/HVAC SYSTEM. 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.
PIT5734D2022-04-18. Service bulletin. VISIBILITY:DEFROSTER/DEFOGGER/HVAC SYSTEM. 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.
PIP5833B2022-02-14. Service bulletin. VISIBILITY:DEFROSTER/DEFOGGER/HVAC SYSTEM. This Preliminary information communicates to technicians to update the program in the DEF controller
PIT5734C2022-02-14. Service bulletin. VISIBILITY:DEFROSTER/DEFOGGER/HVAC SYSTEM:HEATER CORE. 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.
PIP5833A2022-02-14. Service bulletin. VISIBILITY:DEFROSTER/DEFOGGER/HVAC SYSTEM. This Preliminary information communicates to technicians to update the program in the DEF controller
PIT58682021-12-13. Service bulletin. VISIBILITY:DEFROSTER/DEFOGGER/HVAC SYSTEM:HEATER CORE; EQUIPMENT ADAPTIVE/MOBILITY; EQUIPMENT. This Preliminary information communicates an issues will low or poor heater performance on the drivers side. Dealers are to inspect the HVAC temperature door linkage and if ok replace the heater core.
PIT5767A2021-06-14. Service bulletin. VISIBILITY; VISIBILITY:DEFROSTER/DEFOGGER/HVAC SYSTEM:CONDENSOR/EVAPORATOR; VISIBILITY:DEFROSTER/DEFOGGER/HVAC SYSTEM. This Preliminary information communicates an issue with poor a/c performance and to replace the a/c condenser.
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.

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