Sorry, the NHTSA has not posted this TSB document yet.
You can still get the detailed info from Chevrolet for this TSB. Call your local Chevrolet dealer's service department & ask for a copy of TSB# 17-NA-342.
Service Brake Assist Message displayed on Initial Start Up with DTC P050F Set
Condition
Some customers may comment that on first start up they receive a "Service Brake Assist
Message" displayed.
During diagnosis a technician may find DTC P050F set.
Cause This may be due to a calibration within the Electronic Brake Control Module (EBCM) not giving the engine enough time to build system vacuum.
Correction Reprogram the EBCM with the latest calibrations