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.
