T-SB-0028-21

TSB: Some 2012 ? 2014 model year Prius C hybrid vehicles may exhibit a condition in which the brake, ABS, and/or TRAC warning lights are on and/or a Check VSC message displays. Diagnostic Trouble Codes (DTCs) C1391, C1252, C1256, and/or C1253 may also 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.