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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: Engine are shown. Show all

Bulletins, newest first
N202319660 012021-03-01. Service bulletin. EQUIPMENT ADAPTIVE/MOBILITY; EQUIPMENT; ENGINE AND ENGINE COOLING:ENGINE:HARD PARTS INTERNAL/MECHANICAL. Service Update. Certain vehicles may present a broken engine valve spring. This may cause the engine to run rough, an engine knocking or ticking noise, a check engine light illumination, or a possible vehicle stall. Dealers are to perform the inspection procedure contained within this bulletin.
N2023205102021-03-01. Service bulletin. AIR BAGS; ENGINE AND ENGINE COOLING; ELECTRICAL SYSTEM; FUEL SYSTEM, GASOLINE; EQUIPMENT. Customer Satisfaction Program. Certain vehicles, equipped with a gas engine, may have a condition in which the printed circuit board inside of the water pump may have been manufactured incorrectly potentially causing a water pump failure. The vehicle coolant system temperature is monitored and will display multiple warnings to the customer as coolant temperatures rise. At a set coolant temperature, the MIL will illuminate, DTC P2B85 will set in the engine control module (ECM), the oil pressure gauge will indicate high oil pressure and reduced torque with notification to the driver of reduced power will occur. If the customer continues to drive after this warning and the coolant temperature continues to rise, a chime will occur, the AC will be disabled and an additional message instructing the driver to idle will illuminate. If the customer continues to drive the vehicle after all previous warnings and the coolant temperature continues to rise a message the engine will shut down could occur, and the engine will be shut down. Dealers are to replace the water pump.
19NA2182021-02-22. Service bulletin. ENGINE AND ENGINE COOLING. This technical bulletin provides a service procedure to correct a condition of Ticking Noise from the Engine.
19NA1362021-02-22. Service bulletin. ENGINE AND ENGINE COOLING. This service bulletin provides a diagnostic procedure to aid in correcting a customer concern of a Howling, Whining/Whirring Noise, Shudder/Vibration and/or Grinding Noise While in 4HI, 4HI Auto and/or During Parking Lot Maneuvers in Auto Mode.
17NA1662021-02-22. Service bulletin. ENGINE AND ENGINE COOLING. This technical bulletin provides a procedure to measure vibration and install engine mounts to correct a Rough Idle in Drive concern.
N202319660 012021-02-22. Service bulletin. ENGINE AND ENGINE COOLING. Service Update. Certain vehicles may present a broken engine valve spring. This may cause the engine to run rough, an engine knocking or ticking noise, a check engine light illumination, or a possible vehicle stall. Dealers are to perform the inspection procedure contained within this bulletin.
N2023205102021-02-22. Service bulletin. ENGINE AND ENGINE COOLING. Customer Satisfaction Program. Certain vehicles, equipped with a gas engine, may have a condition in which the printed circuit board inside of the water pump may have been manufactured incorrectly potentially causing a water pump failure. The vehicle coolant system temperature is monitored and will display multiple warnings to the customer as coolant temperatures rise. At a set coolant temperature, the MIL will illuminate, DTC P2B85 will set in the engine control module (ECM), the oil pressure gauge will indicate high oil pressure and reduced torque with notification to the driver of reduced power will occur. If the customer continues to drive after this warning and the coolant temperature continues to rise, a chime will occur, the AC will be disabled and an additional message instructing the driver to idle will illuminate. If the customer continues to drive the vehicle after all previous warnings and the coolant temperature continues to rise a message the engine will shut down could occur, and the engine will be shut down. Dealers are to replace the water pump.
N202319660 012021-02-16. Service bulletin. ENGINE; EQUIPMENT. Service Update. Certain vehicles may present a broken engine valve spring. This may cause the engine to run rough, an engine knocking or ticking noise, a check engine light illumination, or a possible vehicle stall. Dealers are to perform the inspection procedure contained within this bulletin.
N2023205102021-02-16. Service bulletin. LANE DEPARTURE; FUEL SYSTEM, GASOLINE; SERVICE BRAKES, HYDRAULIC; ELECTRICAL SYSTEM; AIR BAGS; ENGINE AND ENGINE COOLING; POWER TRAIN. Customer Satisfaction Program. Certain vehicles, equipped with a gas engine, may have a condition in which the printed circuit board inside of the water pump may have been manufactured incorrectly potentially causing a water pump failure. The vehicle coolant system temperature is monitored and will display multiple warnings to the customer as coolant temperatures rise. At a set coolant temperature, the MIL will illuminate, DTC P2B85 will set in the engine control module (ECM), the oil pressure gauge will indicate high oil pressure and reduced torque with notification to the driver of reduced power will occur. If the customer continues to drive after this warning and the coolant temperature continues to rise, a chime will occur, the AC will be disabled and an additional message instructing the driver to idle will illuminate. If the customer continues to drive the vehicle after all previous warnings and the coolant temperature continues to rise a message the engine will shut down could occur, and the engine will be shut down. Dealers are to replace the water pump.
PIT5479D2021-02-16. Service bulletin. ENGINE AND ENGINE COOLING. This Preliminary Information communication provides information to the technician about fluid leaking from the brake caliper piston area found during a service of the vehicle. The substance is actually excess assembly grease from the caliper boot and piston installation. This grease can be cleaned off and the rest of the service completed.
PIE0601A2021-02-01. Service bulletin. ELECTRICAL SYSTEM; ENGINE. This engineering informational bulletin is requesting information from technicians to perform the check list provided and contact the engineer listed in regards to the Service Engine Soon Lamp being illuminated.
090604026S2021-02-01. Service bulletin. EQUIPMENT; EQUIPMENT ADAPTIVE/MOBILITY; ENGINE AND ENGINE COOLING. This bulletin provides information on identifying Non-GM Engine Calibrations for Gasoline Engines using the Tech 2 or GDS 2.
010601011L2021-02-01. Service bulletin. ENGINE AND ENGINE COOLING; EQUIPMENT. This informational bulletin provides guidelines and diagnostic/repair information to technicians regarding vehicle engine oil consumption.
19NA2182021-02-01. Service bulletin. EQUIPMENT ADAPTIVE/MOBILITY; EQUIPMENT; ENGINE AND ENGINE COOLING. This technical bulletin provides a service procedure to correct a condition of Ticking Noise from the Engine.
17NA1662021-02-01. Service bulletin. EQUIPMENT; ENGINE AND ENGINE COOLING. This technical bulletin provides a procedure to measure vibration and install engine mounts to correct a Rough Idle in Drive concern.
N202319660 012021-02-01. Service bulletin. ENGINE AND ENGINE COOLING; EQUIPMENT; EQUIPMENT ADAPTIVE/MOBILITY. Service Update. Certain vehicles may present a broken engine valve spring. This may cause the engine to run rough, an engine knocking or ticking noise, a check engine light illumination, or a possible vehicle stall. Dealers are to perform the inspection procedure contained within this bulletin.
N2023205102021-02-01. Service bulletin. EQUIPMENT ADAPTIVE/MOBILITY; ENGINE AND ENGINE COOLING; EQUIPMENT. Customer Satisfaction Program. Certain vehicles, equipped with a gas engine, may have a condition in which the printed circuit board inside of the water pump may have been manufactured incorrectly potentially causing a water pump failure. The vehicle coolant system temperature is monitored and will display multiple warnings to the customer as coolant temperatures rise. At a set coolant temperature, the MIL will illuminate, DTC P2B85 will set in the engine control module (ECM), the oil pressure gauge will indicate high oil pressure and reduced torque with notification to the driver of reduced power will occur. If the customer continues to drive after this warning and the coolant temperature continues to rise, a chime will occur, the AC will be disabled and an additional message instructing the driver to idle will illuminate. If the customer continues to drive the vehicle after all previous warnings and the coolant temperature continues to rise a message the engine will shut down could occur, and the engine will be shut down. Dealers are to replace the water pump.
PIP5733G2021-01-25. Service bulletin. ENGINE AND ENGINE COOLING:ENGINE:CRANK/CAMSHAFT POSITION SENSOR. This Preliminary information communicates Possible Crank no start or extended crank with DTC p12A6 set current or history. Under Investigation
PIT5479D2021-01-25. Service bulletin. ENGINE AND ENGINE COOLING. This Preliminary Information communication provides information to the technician about fluid leaking from the brake caliper piston area found during a service of the vehicle. The substance is actually excess assembly grease from the caliper boot and piston installation. This grease can be cleaned off and the rest of the service completed.
N2023196602020-12-21. Service bulletin. ENGINE; ELECTRICAL SYSTEM:SOFTWARE. Service Update. Certain vehicles may present a broken engine valve spring. This may cause the engine to run rough, an engine knocking or ticking noise, a check engine light illumination, or a possible vehicle stall. Dealers are to perform the inspection procedure contained within this bulletin.
PIE06012020-12-21. Service bulletin. ELECTRICAL SYSTEM; ENGINE AND ENGINE COOLING:EXHAUST SYSTEM:EMISSION CONTROL. This engineering informational bulletin is requesting information from technicians to perform the check list provided and contact the engineer listed in regards to the Service Engine Soon Lamp being illuminated.
100605002I2020-12-21. Service bulletin. EQUIPMENT; ENGINE AND ENGINE COOLING:EXHAUST SYSTEM. This informational bulletin provides information on Clean Exhaust Filter See Owners Manual Now or Cleaning Exhaust Filter Keep Driving Until Message is Cleared messages Displayed on DIC, DTC P2463 May Be Set.
060089031F2020-12-21. Service bulletin. POWER TRAIN:AUTOMATIC TRANSMISSION; ENGINE. This service bulletin provides information on OEM and Remanufactured Engine and Automatic Transmission/Transaxle Identification.
030604017O2020-12-21. Service bulletin. FUEL SYSTEM, DIESEL; ENGINE AND ENGINE COOLING:ENGINE:DIESEL. This Informational Bulletin provides information on availability of Diesel Fuel additives.
20NA0902020-12-21. Service bulletin. ENGINE AND ENGINE COOLING:ENGINE:ENGINE CONTROL MODULE (ECU/ECM). This informational bulletin provides a way for the technician to identify if the ECM has been modified.

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