Low Pedal
WARNING: This page is about a different car, the 2017 RAM 2500 HD. However, it is still accessible from the selected car via links, so may be relevant.
If a low pedal is experienced, pump the pedal several times. If the pedal comes back up, the most likely causes are worn linings, rotors, drums, rear brakes out of adjustment, or calipers are not sliding on the slide pins. The proper course of action is to inspect and replace all worn component and make the proper adjustments.