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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.

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Bulletins, newest first
N1922667512019-11-12. Service bulletin. ELECTRICAL SYSTEM: INSTRUMENT CLUSTER/PANEL; ENGINE AND ENGINE COOLING. N192266751 - Service Update (9 VINs moved from N192266750 due to different procedure). On certain vehicles that are equipped with a 6.6L diesel engine, may have one or more of the following conditions exist: 1.The instrument panel cluster may incorrectly display the message ?DEF Low? when a diesel engine fluid (DEF) controller internal fault is detected (DTC P20FF), instead of displaying the proper ?Service DEF System? message. 2.The customer may complain of excessive engine fan noise at a low vehicle speed. 3.Under certain conditions, the diagnostic system may set one of the following DTC?s when there is no problem with a component: (P20EE, P226D, P16F3 and P129F). Dealers are to reprogram the engine control module.
N1922667502019-11-12. Service bulletin. ENGINE AND ENGINE COOLING. N192266750 - Service Update. On certain vehicles that are equipped with a 6.6L diesel engine, may have one or more of the following conditions exist: 1.The instrument panel cluster may incorrectly display the message ?DEF Low? when a diesel engine fluid (DEF) controller internal fault is detected (DTC P20FF), instead of displaying the proper ?Service DEF System? message. 2.The customer may complain of excessive engine fan noise at a low vehicle speed. 3.Under certain conditions, the diagnostic system may set one of the following DTC?s when there is no problem with a component: (P20EE, P226D, P16F3 and P129F). Dealers are to reprogram the engine control module.
PIP5670A2019-11-12. Service bulletin. ENGINE AND ENGINE COOLING:ENGINE:GASOLINE:TURBO/SUPERCHARGER. This preliminary information communicates the part restriction for the diesel turbocharger and EGR components. Updated to provide instruction on gathering additional data.
PIP5668A2019-11-12. Service bulletin. ENGINE AND ENGINE COOLING. This Preliminary information communicates to the dealer technician the coolant control valve is on restriction.
PIP56862019-11-12. Service bulletin. EQUIPMENT:APPLIANCE:AIR CONDITIONER. This Preliminary information communicates A vehicle may come into the dealer with a rough idle, lean running concern and/or air leak noise from the PCV system. Upon inspection the technician may find the SES lamp is illuminated and/or DTC?s P0171 and/or P0174 may be in active or stored history. This condition may be caused by an incorrectly installed foul air PCV tube or tube may be damaged
PIT5392D2019-11-12. Service bulletin. VEHICLE SPEED CONTROL:ACCELERATOR PEDAL. This Preliminary Information communication provides information to the technician about vehicles that have a detent / click with a feel of increased resistance when the accelerator pedal is about ¾ of the way. The new accelerator pedal design has a built-in detent position near the last 1/4 of pedal travel. Dealer should communicate to the customer this is a normal operating characteristic of the vehicle and no repair attempts should be performed.
PIT5161G2019-11-12. Service bulletin. FUEL SYSTEM, GASOLINE. This Preliminary Information communication provides information to the technician about vehicles that may have a bump feel or clunk noise at a stop or on launch. Dealer should communicate to the customer this condition is a normal operating characteristic of their vehicle. The bump clunk issue may be due to fuel movement in the fuel tank when not completely full. The condition is eliminated after completely filling the fuel tank.
PIP56852019-11-12. Service bulletin. ELECTRICAL SYSTEM:SOFTWARE. This Preliminary information communicates A vehicle with a customer concern of a SES P0128, Engineering is aware of the concern and working on the a repair. At this time clear the codes and do not replace the thermostat for this concern. There will be a calibration released for the concern in this near future. This PI will be updated when the calibration is released.
PIT57152019-11-12. Service bulletin. ELECTRICAL SYSTEM. This Preliminary Information provides information to the technician about a additional diagnostic tip for a check engine lamp for DTC p3055 and P3056 and the start/Stop being inoperative.
PIT5702A2019-11-12. Service bulletin. ELECTRICAL SYSTEM. This Preliminary information communication provides information to the technician on installing Regular Production Option Code 9L7 Up-fitter Auxiliary Switches. Technician will need to reference the latest version of General Motors Up-fitter Integration Bulletin 153. The information can be found at http://www.gmupfitter.com/ under the "Technical Bulletin" Tab and then "Show all bulletins."
PIP5370E2019-11-12. Service bulletin. ENGINE AND ENGINE COOLING. This Preliminary Information communication provides information to the technician that some vehicle may have an ?Exhaust Fluid Quality Poor? on the Driver Information Center or a diesel exhaust fluid warning lamp on or other exhaust fluid quality related concerns. Technician will inspect the diesel exhaust fluid for contamination. Technician should use Service Information for Contaminants in Diesel Exhaust Fluid Diagnosis and use special tool J26568 or EN50422 Diesel Exhaust Fluid Refractometer for fluid testing.
PIT5657B2019-11-12. Service bulletin. PARKING BRAKE. This Preliminary information communicates how to repair a loose shift cable bracket.
PIT5544C2019-11-12. 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.
PIP5655A2019-11-12. Service bulletin. POWER TRAIN. This Preliminary information communicates to the dealer technician that the 10L1000 transmission have been place on a part restriction. Dealers are to contact the Product Quality Center before replacing the transmission assembly.
PIT5551E2019-11-12. Service bulletin. FORWARD COLLISION AVOIDANCE. 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".
PIP5664C2019-11-12. Service bulletin. ENGINE AND ENGINE COOLING. This Preliminary information communicates to the dealer technician to refer to Service Update N192266750.
PIP5677A2019-11-12. Service bulletin. POWER TRAIN. This Preliminary information communicates to the dealer technician that the 10L60, 10L80 and the 10L90 transmissions have been place on a part restriction. Dealers are to contact the Product Quality Center before replacing the transmission assembly.
PIP56822019-11-12. Service bulletin. ELECTRICAL SYSTEM. This Preliminary information communicates the potential for DTCs P2C7A and/or P14D9 to set, the current procedure to clear them and that an ECM calibration is being developed.
PIE05382019-10-28. Service bulletin. POWER TRAIN. This engineering informational bulletin is requesting information from technicians to perform the check list provided and contact the engineer listed in regards to 8 speed transmission shift quality.
PIE05362019-10-28. Service bulletin. ENGINE AND ENGINE COOLING. This engineering informational bulletin is requesting information from technicians to perform the check list provided and contact the engineer listed in regards to oil leaking from the oil pan.
19NA2162019-10-28. Service bulletin. POWER TRAIN:AUTOMATIC TRANSMISSION. This technical bulletin provides the tech with a procedure to check the t-case for loose fasteners and to re-torque if the cause of the concern.
17NA0732019-10-28. Service bulletin. EQUIPMENT. This warranty administration bulletin provides information regarding the field action courtesy transportation policy.
PIT57132019-10-15. Service bulletin. ENGINE AND ENGINE COOLING. This Preliminary information communicates an issue with the engine wiring harness shorting at the left front cylinder head causing any of the following issues: - IPC gauges sweeping while driving - Several IPC warning messages and MIL displayed - Any combination of the following DTC's: U0073 U0100 u0101 u0121 u0128 U0129 u0131 U0140 U0146 U0422 U2413 P0107 P0641 C2A07
PIP5656C2019-10-15. Service bulletin. ENGINE AND ENGINE COOLING. This Preliminary Information communication advises the technician that the 6.6L Engine (RPO L8T) has been placed on Engine Exchange program and crankshaft has been placed on part ordering restriction. Dealer will need to contact General Motors Product Quality Center for further assistance.
PIP5637D2019-10-15. Service bulletin. ENGINE AND ENGINE COOLING. The Preliminary Information communication advises the technician that the Product Quality Center has a part exchange for 3.0 LM2 engine. The dealer technician is advised to call the GM Product Quality Center for further assistance

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