General Motors (GM) is recalling certain model year 2012 Chevrolet Volt vehicles manufactured March 1, 2012, through April 17, 2012. Due to a brake pressure modulator valve problem, the vehicles do not relieve brake pressure from the front brakes during an anti-lock brake system (ABS), electronic stability control (ESC), or traction control event. One or both front brakes may lock up and not release. Thus, these vehicles fail to conform to Federal Motor Vehicle Safety Standards (FMVSS) No. 126, “Electronic Stability Control Systems”‘ and No. 135, “Light Vehicle Brake Systems.”