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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
PIP5806B2021-09-13. Service bulletin. ENGINE. This preliminary information bulletin instructs to technicians to check the trigger wheel for interfering with the timing chain, and adding a shim to the camshaft position sensor.
PIP5809A2021-09-13. Service bulletin. ENGINE. This Preliminary information communicates Some customers may comment that the SES lamp is illuminated or was Illuminated and turned off. During inspection Technician may notice DTC P0300 (Engine Misfire Detected) active or stored in history. Customers may also comment that the check engine light was flashing while driving up a long grade or smooth road with steady throttle. This condition may be caused by the P0300 diagnostic falsely setting the DTC under certain driving conditions. Upon reviewing GDS data you may notice misfires being recorded on any cylinder but may be more noticeable on cylinders 1 and 6. Engineering is working on an updated calibration to address this concern.
PIC64382021-09-13. Service bulletin. ELECTRICAL SYSTEM. This Preliminary information communicates a condition where the Video Processing Control Module is not able to be programmed to the vehicle. This PI offeres a couple workarounds while Engineering evaluates the concern.
PIP5806A2021-09-13. Service bulletin. BACK OVER PREVENTION; WHEELS. This preliminary information bulletin instructs to technicians to use the Picoscope or a make physical inspection to check for debris on the cam postion sensor and to check for a bent target wheel on the camshaft.
PIP5776E2021-09-13. Service bulletin. STRUCTURE:BODY. This Preliminary information communicates that a vehicle may exhibit a misfire condition resulting in misfire codes P0300-P308. Upon diagnosis it may be discovered the lifter has come apart. It is recommended to replace the lifter guide and the four lifters.
PIP58102021-09-13. Service bulletin. POWER TRAIN:MANUAL TRANSMISSION:SEALS/GASKETS. This Preliminary information communicates that the tool for the HD transfer cases to install the input seal during a repair is incorrect and a new tool is in development.
PIT4261G2021-09-13. Service bulletin. TIRES:SIDEWALL. This Preliminary Information communication provides information to the technician about vehicles with tire sidewall irregularities. This is a visual condition that will not affect durability, reliability or performance of the tires. Dealer should communicate to the customer that slight sidewall indentations are a common characteristic of radial tire construction.
PIP58092021-09-13. Service bulletin. AIR BAGS. This Preliminary information communicates Some customers may comment that the SES lamp is illuminated or was Illuminated and turned off. During inspection Technician may notice DTC P0300 (Engine Misfire Detected) active or stored in history. Customers may also comment that the check engine light was flashing while driving up a long grade or smooth road with steady throttle. This condition may be caused by the P0300 diagnostic falsely setting the DTC under certain driving conditions. Upon reviewing GDS data you may notice misfires being recorded on any cylinder but may be more noticeable on cylinders 1 and 6. Engineering is working on an updated calibration to address this concern.
PIP5632E2021-09-13. Service bulletin. EQUIPMENT:ELECTRICAL:ACCESSORY GENERATOR:CONTROLS. This Preliminary Information communication provides information to the technician that General Motors Technical Assistance Center may ask for Global Diagnostic System 2 Session Log. Technician will need use Global Diagnostic System 2 to send the session logs to General Motors Technical Assistance Center for further assistance on the vehicle in question.
PIT5689D2021-09-13. Service bulletin. ENGINE. This Preliminary information communicates that some customers may comment that after an auto-stop event the engine does not restart and to inspect the engine ground strap. Temporarly on hold while PIE0572 is active. PIE0572 has now ended and reinstating the PI.
PIT5666C2021-09-13. Service bulletin. BACK OVER PREVENTION. This Preliminary information communicates an issue with a noise caused by the engine harness rubbing on the floor pan. Dealers are to reposition the harness to fix the noise.
PIP58082021-09-13. Service bulletin. BACK OVER PREVENTION. This Preliminary information communicates to technicians to replace the ECM and affected sensor if diagnostics leads to replacement of the ECM.
PIP5792B2021-09-13. Service bulletin. FUEL SYSTEM, GASOLINE; POWER TRAIN. This Preliminary information communicates to the dealer technician that if a customer comments that their vehicle equipped with a 6L80, 6L90, 8L90, 10L80, or 10L1000 transmission has a harsh shift, shudder, stall or high transmission fluid temperature concern they should inspect for a twisted transmission cooler line. Technicians are instructed to disconnect the cooler line and untwist it then reconnect the cooler line and inspect the cooler line for being misshaped. Technicians are instructed to replace the cooler line if it is misshaped.
PIP5752M2021-09-13. Service bulletin. BACK OVER PREVENTION. This Preliminary information communicates A Vehicle may have a concern of service engine light, misfire and engine noise with possible of DTC P0300 P0106 P0506, Possible valve spring concern
PIP58162021-09-13. Service bulletin. ENGINE. This Preliminary information communicates A customer vehicle may have a concern of a P0300 setting after bulletin 21-NA-154 has been performed. Unknown Engineering is looking it to this concern
PIT5509H2021-09-13. Service bulletin. AIR BAGS; TRAILER HITCHES; ELECTRICAL SYSTEM. This Preliminary Information communication provides information to the technician on how to diagnose and repair vehicle that may have a "Check Trailer Wiring" or "Service Trailer Brake System? message on the Driver Information Center when a trailer is connected to the vehicle. Diagnostic Trouble Code C1114 set in the Chassis Control Module. Chassis Control Module has to determine the type of trailer brake system that is being used. The Chassis Control Module can be sensitive to a variety of trailer wiring issues. The technician will need to make a trailer tester using Electric Trailer Brake Magnets and 7-way trailer connector to determine if it is a vehicle or trailer issue. If the concern is not duplicated with the tester installed, the vehicle is operating correctly and the focus should be on the trailer wiring or 7 way connector.
PIC5650J2021-09-13. Service bulletin. POWER TRAIN; AIR BAGS. This Preliminary Information communication provides information to the technician about vehicles that have an intermittent no crank, no start, or start stall concern with the security light coming on. Technician may find Diagnostic Trouble Codes B3055, B3060, and/or B3935. Technician should not replace any parts for this concern. If unable to duplicate the concern ask if the customer uses any Radio Frequency Identification Devices when the concern is present. Dealer should also direct their customers to the appropriate section in the Owner manuals that references that the device complies.
PIT5698B2021-09-13. Service bulletin. ELECTRICAL SYSTEM:ADAS:BLINDSPOT:SENSORS. This Preliminary information communicates additional information on how a LIN bus operates and diagnostic tips when working on a LIN bus.
PIP5776F2021-09-13. Service bulletin. ENGINE; EQUIPMENT. This Preliminary information communicates that a vehicle may exhibit a misfire condition resulting in misfire codes P0300-P308. Upon diagnosis it may be discovered the lifter has come apart. It is recommended to replace the lifter guide and the four lifters.
PIP5653K2021-09-13. Service bulletin. SUSPENSION:FRONT. This PI communicates that engineering is investigating a correction to a noise originating in the front of the vehicle.
PIT5509H2021-09-13. Service bulletin. ELECTRICAL SYSTEM. This Preliminary Information communication provides information to the technician on how to diagnose and repair vehicle that may have a "Check Trailer Wiring" or "Service Trailer Brake System? message on the Driver Information Center when a trailer is connected to the vehicle. Diagnostic Trouble Code C1114 set in the Chassis Control Module. Chassis Control Module has to determine the type of trailer brake system that is being used. The Chassis Control Module can be sensitive to a variety of trailer wiring issues. The technician will need to make a trailer tester using Electric Trailer Brake Magnets and 7-way trailer connector to determine if it is a vehicle or trailer issue. If the concern is not duplicated with the tester installed, the vehicle is operating correctly and the focus should be on the trailer wiring or 7 way connector.
N2123368002021-08-09. Service bulletin. EQUIPMENT:ELECTRICAL; POWER TRAIN:TRANSFER CASE (4-WHEEL DRIVE); EQUIPMENT. Service Update. On certain vehicles, the thrust washer was not installed on the transfer case reduction carrier assembly. Dealers are to replace the transfer case.
N2123338002021-08-09. Service bulletin. ENGINE AND ENGINE COOLING:ENGINE:ENGINE CONTROL MODULE (ECU/ECM); ELECTRICAL SYSTEM. Emission Recall. General Motors has decided to conduct a voluntary emissions recall involving certain vehicles equipped with a performance air intake system (LPO RVK or 5W7). The Engine Control Module (ECM) may not have been programmed with the calibrations appropriate for the performance air intake system installed on the engine in these vehicles. Dealers will reprogram the ECM.
N2023160202021-08-09. Service bulletin. EQUIPMENT:ELECTRICAL:INFOTAINMENT:SOFTWARE. Service Update - Radio Software Update (OTA) - Certain 2021 model year vehicles listed above, with an infotainment system, may have a condition where the infotainment system screen will appear black with no audio and no chime at key on during cold temperature conditions. Dealers are to verify radio software level and update if necessary.
N2123328202021-08-09. Service bulletin. EQUIPMENT:APPLIANCE:TV/RADIO/SPEAKERS; EQUIPMENT:ELECTRICAL:RADIO/TAPE DECK/CD ETC.; ELECTRICAL SYSTEM:SOFTWARE. Service Update. Certain vehicles may not be able to access Apps. A most notable improvement list this software update may correct is located at the end of this bulletin for conditions or concerns a customer may experience. Dealers will reprogram the radio.

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