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C15C9 on the 2020 Buick Encore

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 C15C9
PIC6416A2020-06-15. Service bulletin. This Preliminary information communicates to the dealer that if the service AWD (All-Wheel Drive) or AWD (All-Wheel Drive) Off messages are on and there is a history DTC of C15C9 SYM02 set then no repairs are to be made at this time, a software issue was found and Engineering is working on a permanent solution. If the DTC is setting current then published diagnosis needs to be followed.
PIC64162020-05-11. Service bulletin. This Preliminary information communicates to the dealer that if the service AWD (All-Wheel Drive) or AWD (All-Wheel Drive) Off messages are on and there is a history DTC of C15C9 SYM02 set then no repairs are to be made at this time, a software issue was found and Engineering is working on a permanent solution. If the DTC is setting current then published diagnosis needs to be followed.

2 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.