A couple days ago, I did a typical tune up on my old lady's car (plugs, filters, oil). After finishing, I noticed her brake pedal is extremely hard to depress, and it doesn't stop the car very well. I disconnected the negative battery lead before starting, and got to work. Never touched any of the brake lines or anything, so I'm very confused as to how this happened. I typically work on older vehicles, primarily GMs, so I'm not very knowledgeable on how these newer cars work. Initially, I thought there might be built up pressure in the line, so I went ahead and bled the lines. Still nothing. As of now, there's a green bar on the dash that fills up with small white bars as I'm driving (no clue what that is) and a symbol for the brake pedal above it. Haven't had time to get a picture, but if it would help, I can try to get one up when I'm off of work. Any help would be much appreciated.