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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.

By type

By component

By trouble code

By topic

Only bulletins with component: Engine are shown. Show all

Bulletins, newest first
PIP5175D2020-08-10. Service bulletin. POWER TRAIN:AUTOMATIC TRANSMISSION:INTERNAL:GEARS; ENGINE AND ENGINE COOLING. 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.
20NA1002020-08-10. Service bulletin. ENGINE; ELECTRICAL SYSTEM. This informational bulletin provides information for dealers/technicians on Engine Control Module Calibration for T1 L3B Engine with DTC P26BB Set.
16NA3802020-08-10. Service bulletin. ENGINE AND ENGINE COOLING:EXHAUST SYSTEM:MANIFOLD/HEADER/MUFFLER/TAIL PIPE. This informational bulletin provides a procedure on how to perform a quick test to check if the DPF is the cause of excessive soot from the tailpipe.
N1922878402020-06-29. Service bulletin. ELECTRICAL SYSTEM:WIRING; ENGINE. Service Update - Certain vehicles equipped with a 2.7L turbo engine (RPO L3B), may have a condition where the engine wiring harness may have been wrapped and/or routed incorrectly, creating the potential for wear-through in several locations. If this occurred it could allow the engine harness to short to ground and/or be severed, which may lead to a check engine light, reduced engine power, no start condition or in rare cases a stall. Dealers are to inspect harness for correct tape wrapping and install engine harness sleeves.
N2023007912020-06-29. Service bulletin. ENGINE AND ENGINE COOLING:EXHAUST SYSTEM; FUEL SYSTEM, DIESEL; ENGINE AND ENGINE COOLING:ENGINE:DIESEL. Service Update - In some vehicles, equipped with diesel engines, the Diesel Exhaust Fluid (DEF) system may not immediately reactivate, as it should, after the vehicle?s control system finds that a DEF heater fault is no longer present. In these vehicles, after such a fault is detected as absent, DEF system reactivation, including DEF injection, may not occur until the ignition key is cycled. Dealers are to reprogram the reductant control module.
PIE0563A2020-06-22. Service bulletin. ENGINE. This engineering information (EI) 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.
140604004G2020-06-22. Service bulletin. ENGINE. This informational bulletin explains the normal noises an engine may make when the ambient temperature outside is cold or the vehicle has sat for a few hours.
030601023D2020-06-22. Service bulletin. ENGINE. This information bulletin explains how to measure for oil consumption and possible reasons for loss of oil.
20NA0982020-06-22. Service bulletin. ENGINE; FUEL SYSTEM, GASOLINE:FUEL INJECTION SYSTEM:INJECTORS. This informational bulletin explains to the tech on how to order a new fuel injector by matching the part number on the part and ordering it from the EPC.
20NA0962020-06-22. Service bulletin. ENGINE; ELECTRICAL SYSTEM:SOFTWARE. This informational bulletin provides information for dealers/technicians on Glow Plug Control Module Update.
20NA0902020-06-22. Service bulletin. ENGINE AND ENGINE COOLING; ELECTRICAL SYSTEM. This informational bulletin provides a way for the technician to identify if the ECM has been modified.
20NA0432020-06-22. Service bulletin. ENGINE AND ENGINE COOLING. This informational bulletin advises the technician to not replace the TMAP sensor, clean it using air or harsh chemicals but allow time for the sensor to thaw.
19NA2182020-06-22. Service bulletin. ENGINE AND ENGINE COOLING. This technical bulletin provides a service procedure to correct a condition of Ticking Noise from the Engine.
16NA3832020-06-22. Service bulletin. ENGINE; FUEL SYSTEM, GASOLINE:FUEL INJECTION SYSTEM; EQUIPMENT ADAPTIVE/MOBILITY. This technical bulletin advises of a new fuel injection cleaner kit used for decarbonizing the intake valves to correct conditions of rough idle, Crank no start, extended crank or misfire, MIL with DTCs, and explains how Top Tier fuels should be used to reduce carbon build-up.
PIT5713A2020-06-15. 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 P0117 P0119 P0641 C2A07
PIP5504D2020-06-15. Service bulletin. ENGINE AND ENGINE COOLING. This Preliminary Information communication provides information and definitions to the technician about vehicles that have fishbite, chuggle, misfire, AFM disturbances or torque converter shudder/vibration concerns. Technician are advised to use PICO software to determine root cause of the concern. If torque converter shudder is confirmed technicians are referred to Torque Converter Diagnosis in SI.
PIE05632020-06-01. Service bulletin. EQUIPMENT:MECHANICAL; ENGINE. This engineering information (EI) 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.
PIE0555A2020-06-01. Service bulletin. ENGINE; EQUIPMENT:OTHER:OWNERS/SERVICE/OTHER MANUAL. This engineering information (EI) is requesting information from the field on vehicles experiencing reduced engine power. GM Engineering needs to gather information to root cause the customer concern and develop a field fix.
20NA0832020-05-26. Service bulletin. ENGINE; ELECTRICAL SYSTEM. This technical bulletin provides a procedure to check the oil level for correct reading and oil pressure switch is in working order.
20NA0822020-05-26. Service bulletin. ENGINE; ELECTRICAL SYSTEM. This informational bulletin explains why more DEF is being used in diesel engines due to new emission standards.
PIP5719B2020-05-11. Service bulletin. ENGINE AND ENGINE COOLING. This Preliminary information communicates the possibility of dtc P12A6 with the possibility of a crank no start or extended crank concern.
PIP57242020-05-11. Service bulletin. ENGINE AND ENGINE COOLING. This Preliminary information communicates The vehicle may have an SES lamp with any of the following DTC P06DA, P06DB, P06DC, P250A, P0300, P0340, P0341, P0335, P0336, P0641, P0011, P0010, P2088, P2089, and/or P2230. Possible crank no start or a stall. Possible wiring jumper harness pintched between the X154 connector bracket and the front engine cover on lower left side of the engine.
PIP5670E2020-05-11. Service bulletin. ENGINE AND ENGINE COOLING. This preliminary information communicates the part restriction for the diesel turbocharger and EGR components. Updated to provide instruction on gathering additional data.
PIP5667C2020-05-11. Service bulletin. ENGINE AND ENGINE COOLING. This Preliminary information communicates the part restriction for the diesel engine air delivery and exhaust system components
PIP5719A2020-05-11. Service bulletin. ENGINE AND ENGINE COOLING. This Preliminary information communicates the possibility of dtc P12A6 with the possibility of a crank no start or extended crank concern.

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