WenmarOpen by Wenmar Pro

C1391 on the 2012 Toyota Prius V

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 C1391
T-SB-0089-202020-10-26. Service bulletin. TSB: Some 2012 ? 2014 model year Prius V hybrid vehicles may exhibit a condition where the brake, ABS, and/or TRAC warning light(s) are on and/or a Check VSC message displays. Diagnostic Trouble Codes (DTCs) C1391, C1252, C1256, or C1253 may be stored. This condition may be caused by a small internal brake fluid leak inside the brake booster assembly with master cylinder. Follow the Repair Procedure in this bulletin to address this condition.
T-SB-0024-192019-04-15. Service bulletin. TSB: Some 2011 ? 2015 model year Prius and 2012 ? 2015 model year Prius Plug-in Hybrid vehicles may exhibit a condition where the brake, ABS, and/or TRAC warning light(s) are on and/or a Check VSC message displays. Diagnostic Trouble Codes (DTCs) C1391, C1252, C1256, and C1253 may be stored. This condition may be caused by a small internal brake fluid leak inside the brake booster assembly with master cylinder. Follow the Repair Procedure in this bulletin to address this condition.

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.