Service bulletins for the 2020 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.
1990 on file from NHTSA, as of 2026-10-19.
By type
By component
By trouble code
By topic
| 21NA237 | 2021-12-27. Service bulletin. EQUIPMENT; ENGINE AND ENGINE COOLING:COOLING SYSTEM:HOSES/LINES/PIPING/FITTINGS. THis technical bulletin provides a procedure to perform a cooling system flush to remove possible debris from the cooling system pipes. |
|---|---|
| 21NA149 | 2021-12-27. Service bulletin. ENGINE AND ENGINE COOLING:ENGINE; ELECTRICAL SYSTEM:WIRING. This technical bulletin provides repair information to correct a customer concern of Engine Wire Harness Chafing. |
| 21NA091 | 2021-12-27. Service bulletin. BACK OVER PREVENTION; EQUIPMENT. This service bulletin provides information for customers/dealers/technicians on Normal Rearview Camera Display Operation - Flashing Diamond - Spot - or UFO like image on Rear View Camera Display. |
| 20NA188 | 2021-12-27. Service bulletin. BACK OVER PREVENTION; ELECTRICAL SYSTEM; EQUIPMENT ADAPTIVE/MOBILITY; EQUIPMENT. This technical bulletin provides repair information to correct a customer concern of Rear View Camera Image Flickers When Brake Lamps or Turn Signals are On. |
| 19NA104 | 2021-12-27. Service bulletin. ENGINE AND ENGINE COOLING; EQUIPMENT. This service bulletin provides information for dealers/technicians and customers on steam/vapor coming from the front grille or radiator area. |
| 20NA132 | 2021-12-20. Service bulletin. ELECTRICAL SYSTEM:12V/24V/48V BATTERY. This warranty administration bulletin provides policy information on the requirements for battery testing and warranty replacements. |
| 20NA110 | 2021-12-20. Service bulletin. FUEL SYSTEM, GASOLINE. This service bulletin advises the technician on what to do if the DEF pump has been replaced and perform a leak test to prime the pump. |
| 20NA078 | 2021-12-20. Service bulletin. SUSPENSION. This technical bulletin provides a procedure to replace the 4 5 6 clutch housing if the bushing was found worn and the cause of the customers concern. |
| 20NA020 | 2021-12-20. Service bulletin. SERVICE BRAKES, HYDRAULIC. This technical bulleti provides a procedure to replace the front and rear brake pads if the brakes are squealing. |
| 19NA129 | 2021-12-20. Service bulletin. BACK OVER PREVENTION. This technical bulletin provides repair information to correct a customer concern of a squeak and/or clunking noise coming from the rear of the vehicle. |
| 18NA073 | 2021-12-20. Service bulletin. ENGINE. 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. |
| PIT5868 | 2021-12-13. 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. |
| PIP5762B | 2021-12-13. Service bulletin. EQUIPMENT ADAPTIVE/MOBILITY; ENGINE AND ENGINE COOLING:ENGINE:DIESEL; EQUIPMENT. This preliminary information communicates to technicians a possible valve cover causing oil consusmption, and the repair. |
| PIP5646D | 2021-12-13. Service bulletin. WHEELS; ELECTRICAL SYSTEM; POWER TRAIN. This Preliminary information communicates to the dealer technician that some customers may comment the rear wheels locked up at low speeds after a hot soak. Technicians may find DTC's P2724, P2727 or P2729 set. Technician's are advised to replace the TCM to address this concern. |
| PIT5448G | 2021-12-13. Service bulletin. ENGINE. This Preliminary Information communication advises the technician with a tip when the vehicle stops running after it has been idling for 2.5 hours. This is normal operation of the vehicle built with regular production code BTM and without Regular Production Option Code AVF. If the vehicle was built with regular production code BTM and AVF only has a 1 hour idle time. |
| PIP5806D | 2021-10-25. Service bulletin. POWER TRAIN. 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. |
| PIT5853 | 2021-10-25. Service bulletin. STRUCTURE. This Preliminary information communicates information on correcting a rattle noise on driver side of cowl heat shield. |
| PIT5752B | 2021-10-25. Service bulletin. EQUIPMENT. This Preliminary information communicates multiple vehicle issues caused by an aftermarket device and it gives dealership information where to inspect for this device. |
| PIT5544E | 2021-10-25. Service bulletin. STEERING. 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. |
| PIT5387K | 2021-09-13. Service bulletin. ELECTRICAL SYSTEM. This Preliminary Information communication provides information to the technician how to repair vehicles that Instrument Panel Cluster, Radio, and Heater-Vent-Air Conditioning display blanks out, Bluetooth phone or Pandora connection dropped, the radio station or volume changes when operating the snow plow. Please advise the customer that engineering is aware of this concern and working on this issue. |
| PIT5662F | 2021-09-13. Service bulletin. ELECTRICAL SYSTEM:ADAS:PARKING ASSIST:WARNING; PARKING BRAKE. This Preliminary information communicates information to diagnose DTC C056D or C056E. |
| PIC6438B | 2021-09-13. Service bulletin. ELECTRICAL SYSTEM; EQUIPMENT. 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. |
| PIP5794B | 2021-09-13. Service bulletin. ENGINE. This Preliminary information communicates diagnostics to the dealer involving a vehicle shudder concern caused by the camshaft actuator system that can be mistaken for a transmission issue. |
| PIT5743A | 2021-09-13. Service bulletin. ELECTRICAL SYSTEM. This Preliminary information communicates diagnostic tips when trying to root cause a SES MIL with DTC's B2B0D and B2B0E. Main cause is aftermarket electrical devices spliced into the ignition main fuses. |
| PIP5806C | 2021-09-13. Service bulletin. ENGINE; ELECTRICAL SYSTEM. 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. |
The summaries are NHTSA's. Each bulletin's page links NHTSA's copy of the manufacturer's document.