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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

Bulletins, newest first
PIT4506H2025-02-25. Service bulletin. UNKNOWN OR OTHER. This Preliminary Information communication provides information to the technician that some owners of Heavy Duty Trucks and Utilities may ask if they can lower their tire pressures. Tire pressures being set to the "Tire and Loading Label" will ensure the safe handling and ride characteristics of the truck and should not be lowered.
PIP5358D2025-02-25. Service bulletin. UNKNOWN OR OTHER. This Preliminary Information communication provides information to the technician about vehicles that have an unusual noise and is difficult to identify, isolate or pinpoint. Technician should get record a sound clip or take a video of the noise for assessment by engineering. Technician will need to call General Motors Technical Assistance Center for further assistance.
PIT5551Q2025-02-25. Service bulletin. UNKNOWN OR OTHER. This Preliminary information communicates a "Forward Collision System Reduced" message displayed on the DIC when the Forward Automatic Braking has been set to the "Alert" setting. This is normal when the FAB has been set to "Alert".
PIT5744E2025-02-25. Service bulletin. UNKNOWN OR OTHER. This Preliminary information communicates information on how to disable the Side Blind Zone Detection and Park Assist systems when a customer removes the pickup box from the vehicle to install an aftermarket bed or body.
PIT6276A2025-02-25. Service bulletin. UNKNOWN OR OTHER. This Preliminary information communicates an issues with a service keyless entry message caused by aftermarket door handle covers and they should be removed.
21-NA-1382025-02-19. Service bulletin. SUSPENSION. This service bulletin provides a repair procedure to correct a customer concern of a Squeak, Grind or Clunking Noise from Rear Leaf Springs.
16-NA-0192025-02-19. Service bulletin. POWER TRAIN. This service bulletin provides information on Transmission Adaptive Functions and Correcting Low Mileage Harsh Shifts, Slips, or Flares.
PIT5986C2025-02-18. Service bulletin. UNKNOWN OR OTHER. This Preliminary information communicates a diagnostic tip for a thump, click, pop, clunk type noise that is heard from the front end. Dealers are to inspect for something contacting the grill shutters as they open and close.
PIT6132B2025-02-18. Service bulletin. UNKNOWN OR OTHER. This Preliminary information communicates an issues with the HVAC making a hum buzz noise when the blower is set to a higher speed. Engineering is working on a new HVAC door seal material to correct the noise.
23-NA-0642025-02-12. Service bulletin. ELECTRICAL SYSTEM; UNKNOWN OR OTHER. This service bulletin provides information on the Transport Mode Feature, also known as Logistics mode, which is used to increase the 12V Battery stand time of the vehicle during transit and or long period of stand time at the dealerships.
22-NA-2442025-02-12. Service bulletin. UNKNOWN OR OTHER; STRUCTURE:BODY. This warranty administration service bulletin provides information about GM Accessories - Dealer-Installed, Repaired or Replaced During Warranty Coverage Period.
22-NA-0742025-02-12. Service bulletin. ENGINE. This service bulletin provides service information to technicians on guidelines to replace Oil Cooler, Oil Cooler Lines and Oil Tank if the engine was replaced where large amounts of debris has flowed throughout the oiling system.
21-NA-0432025-02-12. Service bulletin. VISIBILITY/WIPER; SERVICE BRAKES; ENGINE; ELECTRICAL SYSTEM; WHEELS. This bulletin advises the dealers to maintain the vehicle stock on hand by doing a full inspection on the vehicles before being sold (prepping) to the customer.
21-NA-1352025-02-12. Service bulletin. UNKNOWN OR OTHER; ELECTRICAL SYSTEM. This service bulletin provides information to inform dealership personnel about Law Enforcement and Government vehicles that request to disable or enable content.
10-08-110-001L2025-02-11. Service bulletin. STRUCTURE:BODY; VEHICLE SPEED CONTROL. This service bulletin provides information on proper use of floor mats.
01-08-42-001Q2025-02-11. Service bulletin. EXTERIOR LIGHTING. This service bulletin provides information on Exterior Lamp Condensation and Water Leak Information and Replacement Guidelines.
PIE08122025-02-11. Service bulletin. FUEL/PROPULSION SYSTEM; ENGINE. This engineering information (EI) is requesting information from technicians to perform the check list provided and contact the engineer listed in regard to the vehicle having loss of power and/or having the MIL illuminated on the Driver Information Center (DIC).
PIT5479G2025-02-10. Service bulletin. UNKNOWN OR OTHER. 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.
PIT5990C2025-02-10. Service bulletin. UNKNOWN OR OTHER. This Preliminary information communicates an issue with a wind noise while driving at highway speeds and dealers are to inspect the body harness pass through for being full seated into the cowl.
PIP5175F2025-02-10. Service bulletin. POWER TRAIN. This Preliminary Information communication provides information to the technician about vehicles that may have a delayed engagement into drive, shudder at a launch, or the transmission is slipping when shifting into 1st, 2nd, 3rd or 4th gears. This may be due to loose stator support to pump cover bolts causing a leak at the stator support to pump cover gasket. Technician will check for the bolts to be loose. If any of the bolts are loose or the gasket is misaligned or leaking, the transmission pump cover must be replaced and the 1234 clutch plates should be inspected for being distressed and repaired as needed.
20-NA-1752025-02-08. Service bulletin. STRUCTURE:BODY. This technical bulletin provides repair information to correct a customer concern of vertical misalignment between cab and pickup box on driver side of vehicle.
19-NA-2572025-02-08. Service bulletin. STRUCTURE:BODY. This technical bulletin provides repair information to correct a customer concern of the pickup box being out of alignment.
22-NA-2102025-02-05. Service bulletin. ELECTRICAL SYSTEM; ENGINE. This technical bulletin provides a procedure to locate and repair a broken ground stud at the NOx converter.
22-NA-1722025-02-05. Service bulletin. WHEELS; ELECTRICAL SYSTEM. This technical bulletin provides repair information to correct a customer concern of Trailer Tire Pressure Only Reading Up To 100 PSI, New Parts To Increase To 147 PSI.
PIT5544H2025-02-03. Service bulletin. UNKNOWN OR OTHER. This Preliminary information communicates information on a hydrauilc rush type noise from the power steering gear. This noise is a characteristic of the new Active Hydraulic Assist System RPO NV8 and no repairs should be made. The noise is most noticeable in the cab at idle, in park, with all accessories turned off.

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