Q: The emergency brake is not working and multiple brake lights are on

Recently got a 2007 Jeep Liberty with abs light on, traction control light on, and esp bas light on, cruise control doesn't work , and speedometer acts weird sometimes, check engine light came on for 30 min then went off, autozone found a 0501 code which points towards the speed sensor, the person I got it from had the spring on the backing plates on both rear wheels zip tied to the shocks and he said that was why the lights were on and the ebrake doesn't work because of that as well. Also when I first take off I can hear a slight knocking from one of the wheels on the driver side but it's only for about 25 feet and then it goes away once I pick up a higher speed. I had trouble finding info on this issue and I plan on fixing it myself. Any advice would be appreciated

My car has 91000 miles.
My car has an automatic transmission.