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Service bulletin PIT5599

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.

The communication, as NHTSA indexes it (as of 2026-10-19)
TypeService bulletin
NHTSA id10125125
Published by NHTSA2017-12-14
Manufacturer's numberPIT5599
Manufacturer's date2017-11-20
NHTSA componentELECTRICAL SYSTEM:SOFTWARE; ELECTRICAL SYSTEM

NHTSA's summary

This Preliminary information communicates a false setting of DTCU0121 in the FVCM due to a FVCM software anomaly. Code U0121 will set and be moved to history in the FVCM with each ignition cycle.

The document

The document is the manufacturer's. This site does not hold it. NHTSA files a document at one of these two addresses; we have not asked NHTSA which.

Components

Electrical system, Software

Trouble codes named

U0121

Vehicles listed
BUICK LACROSSE2017, 2018
CADILLAC CT62016
CADILLAC CT6 PLUG-IN HYBRID2017, 2018 (the catalog's model; the bulletin names a series or trim of it)
CADILLAC ESCALADE2016, 2017, 2018
CADILLAC XT52017, 2018
CHEVROLET BOLT EV2017, 2018
CHEVROLET MALIBU2016, 2017, 2018
CHEVROLET SILVERADO 15002016, 2017 (the catalog's model; the bulletin names a series or trim of it)
CHEVROLET SILVERADO 25002018 (the catalog's model; the bulletin names a series or trim of it)
CHEVROLET SUBURBAN2016, 2017, 2018
CHEVROLET TAHOE2016, 2017, 2018
GMC ACADIA2017, 2018
GMC SIERRA 15002016, 2017 (the catalog's model; the bulletin names a series or trim of it)
GMC SIERRA 35002018 (the catalog's model; the bulletin names a series or trim of it)
GMC YUKON2016, 2017, 2018

Listing a model year does not mean every vehicle of it is concerned: the document says which.

Recalls for the same vehicles and component
19V6420002019-09-06. ENGINE; ELECTRICAL SYSTEM:SOFTWARE; FUEL SYSTEM, GASOLINE:FUEL INJECTION SYSTEM:INJECTORS
16V0840002016-02-11. ELECTRICAL SYSTEM:SOFTWARE

A recall listed here may apply to some of the same vehicles. Only the manufacturer can say whether it applies to one vehicle.

Other bulletins for the same vehicles and component
20-NA-1322024-04-05. Service bulletin. This warranty administration bulletin provides policy information on the requirements for 12V battery testing and warranty replacements.
PIP5632G2023-01-30. Service bulletin. 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.
PIP4902Q2023-01-30. Service bulletin. 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.
PIP58142023-01-30. Service bulletin. This Preliminary information communicates that there some service parts released to dealers missing software.
N212345750012022-06-27. Service bulletin. High Voltage Battery Software Update
N2123457502022-06-27. Service bulletin. High Voltage Battery Software Update
174192021-04-30. Service bulletin. Condition Certain 2018 model year Chevrolet Silverado HD and GMC Sierra HD vehicles, equipped with 6.6L diesel engine (RPO L5P) and Allison transmission (RPO MW7), may have a condition in which the automatic transmission has rough upshifts. Correction Reprogram the transmission control module (TCM).
15-NA-0832021-04-20. Service bulletin. Recovery Process from a Controller Reprogramming Interruption During service reprogramming of the T87 TCM, some technicians may notice the TCM may fail during the reprogramming event and become unresponsive to the Service Programming System (SPS), unresponsive to the GDS2 tool. This bulletin addresses corrective actions to attempt to recover the module before declaring the TCM as a bad part and replacing. During reprogramming, an interruption can cause the module to lock up. A module reset may recover the TCM
21NA0102021-03-01. Service bulletin. This technical bulletin provides a procedure to reset the DTCs and take the vehicle for a test drive to verify the codes do not return.
20NA2242021-02-01. Service bulletin. This service bulletin provides a procedure to inspect the A/C compressor failure due to a combination of low refrigerant and/or PAG oil to correct a condition of Air Conditioning Blows Warm Air and/or Does Not Get Cold.