2011 Prius Brake Pedal Hits Floor After Re-installing HV BATTERY

I removed my Hybrid Battery and reinstalled it, now my brake pedal goes to the floor/ stop. The brake pedal didn't travel that far before I removed the battery. Did I miss a step? I test drove the car which still brakes, but when sitting at a stop position you can press it to the floor/stop and the warning light (curvy road with car) goes on and off. The reason I took the Hybrid battery out was because the dealer said I needed to replace the Hybrid battery unit ($3600.00). After testing each cells voltage (which was good) and cleaning the dirt/ dust off the fan blades no trouble codes came back yet. Test drove about 40 miles. So now I have the brake issue.