2002 Brake Pedal goes to floor

Hello, I'm not sure if this is something I'm capable of troubleshooting on my own or not, but would like to be aware of the likely problems so when a mechanic checks things out I can be sure he knows what he's doing. When the brake pedal is pushed it goes all the way to the floor but will stop the car. The ABS light is on, but no alarm. Running a jumper wire I get codes 59 and 64. Brake fluid is not low.

Thanks for any help.