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
| PIP5792A | 2021-06-14. Service bulletin. POWER TRAIN; FUEL SYSTEM, GASOLINE. 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 or stall 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. |
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| PIP5776D | 2021-06-14. Service bulletin. ENGINE. 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. |
| PIT4322L | 2021-06-14. Service bulletin. ELECTRONIC STABILITY CONTROL:AUTOMATIC (ASC). This Preliminary Information communication provides information to the technician about vehicles that have an unwanted Stability Activation and/or a Service Stability message on the Driver Information Center. Technician may find a Diagnostic Trouble Code C0710. Technician should inspect for vehicles modifications before any in-depth diagnostics are performed. |
| PIT5746A | 2021-06-14. Service bulletin. EQUIPMENT. This Preliminary information communicates information on how dealers can contact the supplier for Associated Accessories offered through GM. |
| PIP5805 | 2021-06-14. Service bulletin. ENGINE. This Preliminary information communicates that the performance air cleaner kit (cold air intake system) can only be installed on vehicles that had the option ordered for the vehicle when it was produced. This performance air filter kit can not be installed on vehicles that were not ordered / produced with this option. This document also reinforces, the vehicles that did have the kit ordered and installed, a calibration is needed to make the kit work properly or DTC's may set. |
| PIT5767A | 2021-06-14. 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. |
| PIT5839A | 2021-06-14. Service bulletin. EQUIPMENT:APPLIANCE:TV/RADIO/SPEAKERS; EQUIPMENT. This Preliminary information communicates to GM dealers that the above mentioned concern is software related and that General Motors is working on a solution. |
| PIE0628 | 2021-06-07. Service bulletin. EXTERIOR LIGHTING; ELECTRICAL SYSTEM. This engineering information (EI) is requesting information from technicians to perform the check list provided and contact the engineer listed in regards to the Malfunction Indicator Lamp illuminated on Driver Information Center (DIC) with DTCs P3055, P3056 Set. |
| PIE0615A | 2021-06-07. Service bulletin. POWER TRAIN; SERVICE BRAKES. This engineering informational bulletin is requesting information from technicians to perform the check list provided and contact the engineer listed in regards on a tick and/or ping type noise heard from the Propeller Shaft during acceleration and/or braking. |
| 070842006P | 2021-06-07. Service bulletin. ELECTRICAL SYSTEM. This service bulletin provides technicians with information on available BCM calibrations to restore bulb outage detection on vehicles produced by a second stage manufacturer (Upfitter), and/or turn signals flash fast after factory box removed. |
| 070089036J | 2021-06-07. Service bulletin. EQUIPMENT. This service bulletin provides information on Enhancing Field Product Reports with Digital Pictures. |
| 050308002I | 2021-06-07. Service bulletin. SUSPENSION. This service bulletin provides information to dealership personnel on diagnosis and replacement of shock absorber and strut due to fluid leak. |
| 020089002T | 2021-06-07. Service bulletin. EQUIPMENT. This service bulletin provides information for dealers/technicians on When and How to Submit a Field Product Report (FPR) (U.S. Dealers Only). |
| 000601026N | 2021-06-07. Service bulletin. ENGINE. This service bulletin provides information on replacing the intake manifold when the engine is replaced after severe internal engine damage. |
| 21NA106 | 2021-05-24. Service bulletin. POWER TRAIN. This informational bulletin advises the technician to verify the TCM is asleep before trying to repair the transmission in order for all the codes to be re-set. |
| 21NA103 | 2021-05-24. Service bulletin. EQUIPMENT. This service bulletin provides information regarding Witness Marks from Panel Adjustments Made During Manufacturing and that it is considered a normal condition. |
| 21NA097 | 2021-05-24. Service bulletin. EQUIPMENT:APPLIANCE:ELECTRIC WATER HEATER. This technical bulletin provides a procedure to install a pice of foam between the heater core pipes to correct the customers concern. |
| 21NA089 | 2021-05-24. Service bulletin. SERVICE BRAKES, AIR:DISC:CALIPER. This technical bulletin provides a procedure to replace the rear calipers if found packed for of mud and debris. |
| 21NA068 | 2021-05-24. Service bulletin. EQUIPMENT:ELECTRICAL. This warranty administration bulletin provides policy information requirements applicable to key fob replacement under the New Vehicle Limited Warranty or under a Replacement Parts Warranty on 2017-2022 and newer model year vehicles with RPO ATH and AVJ (U.S. Only). |
| 20NA218 | 2021-05-24. Service bulletin. POWER TRAIN. This service bulletin provides repair information to correct a customer concern of Possible Crank No Start or Extended Crank with DTC P12A6. |
| 20NA038 | 2021-05-24. Service bulletin. EQUIPMENT:OTHER:OWNERS/SERVICE/OTHER MANUAL. This informational bulletin explains the difference in AFM and DFM engines and what is and is not activated during this occurrence. |
| 18NA146 | 2021-05-24. Service bulletin. EQUIPMENT. This warranty administration bulletin provides policy information, proper labor operation selection and causal part identification for warranty transactions (U.S. Only). |
| 18NA073 | 2021-05-24. Service bulletin. EQUIPMENT. This service bulletin provides graphics, information and guidelines for engine component wear to assist service personnel as a guideline to perform necessary engine repairs and prevent unnecessary engine replacement. |
| 16NA338 | 2021-05-24. Service bulletin. POWER TRAIN. This Warranty Admin service bulletin provides guidelines for Dealers Not Required and for Dealers Required to Contact the PQC for engine or transmission assembly replacement and explains the PQC process, GWM Transaction submission, vehicle service record retention and proper handling of assembly returns for Canadian Dealers only. |
| PIP5748F | 2021-05-17. Service bulletin. ELECTRICAL SYSTEM. This Preliminary information communicates to the technition instructions to replace the particulate matter sensor for a P1488 and to use the special labor operation for tracking purposes. |
The summaries are NHTSA's. Each bulletin's page links NHTSA's copy of the manufacturer's document.