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B124B on the 2015 Buick LaCrosse

The bulletins listed name this code in NHTSA's summary, or are about the same components. A bulletin or a recall listed here may apply to the model year. None of it is a diagnosis.

This code is specific to a manufacturer and is not described here. Its meaning is in the manufacturer's service information.

Bulletins for this model year that name B124B
PIC5910C2017-08-15. Service bulletin. This Preliminary Information communication provides information to the technician about vehicles that have a Diagnostic Trouble Code B124B sym 04 in the HMI module. Technician should check the USB port operations if no issue found it should be considered a false code and no components should be replaced. If the USB port is inoperative technician should follow published Service Information diagnosis for Auxiliary Audio Input Malfunction.
PIC5910B2017-08-15. Service bulletin. This Preliminary Information communication provides information to the technician about vehicles that may have Diagnostic Trouble Code B124B sym 04 set in the Human Machine Interface. When working on the 2014 model year Lacrosse the Human Machine Interface can be reprogrammed using Service Programming System. If working on a 2015 model year Lacrosse, Colorado, or Canyon engineering is currently working on new calibrations to correct this concern.
PIC5910A2017-08-15. Service bulletin. This Preliminary Information communication provides information to the technician about vehicles that may have a Diagnostic Trouble Code B124B sym 04 stored in the Human Machine Interface module. For model year 2014 the Human Machine Interface should be reprogrammed with the latest calibration from TIS2Web. For model year 2015 engineering is currently working on new calibrations to correct this concern.
PIC5910A2017-03-14. Service bulletin. THIS PRELIMINARY INFORMATION COMMUNICATION PROVIDES INFORMATION TO THE TECHNICIAN ABOUT VEHICLES THAT MAY HAVE A DIAGNOSTIC TROUBLE CODE B124B SYM 04 STORED IN THE HUMAN MACHINE INTERFACE MODULE. FOR MODEL YEAR 2014 THE HUMAN MACHINE INTERFACE SHOULD BE REPROGRAMMED WITH THE LATEST CALIBRATION FROM TIS2WEB. FOR MODEL YEAR 2015 ENGINEERING IS CURRENTLY WORKING ON NEW CALIBRATIONS TO CORRECT THIS CONCERN.

4 on file from NHTSA, as of 2026-10-19. See them in the bulletin list. A bulletin lists model years: read the document for which vehicles it concerns.