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B12C5 on the 2016 Honda Pilot

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 B12C5
ONLY93021620212021-02-26. Service bulletin. Owner Notification Letter - The vehicle may not start upon first press of the ENGINE START/STOP button. Also, the MID displays the error message KEYLESS START SYSTEM ERROR, and DTC B12C5 (Engine Start/Stop Switch Failure) is stored. American Honda is extending the warranty on the engine start/stop switch to 9 years from the original date of purchase or 125,000 miles, whichever comes first.
A20-1172020-12-19. Service bulletin. Service Bulletin - The vehicle may not start upon first press of the ENGINE START/STOP button. Also, MID displays the error message KEYLESS START SYSTEM ERROR, and DTC B12C5 (Engine Start/Stop Switch Failure) is stored. American Honda is extending the warranty for the keyless start system on these vehicles to 9 years from the original date of purchase or 125,000 miles, whichever comes first.

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.