ABS DSC Lights question
 

I have the lights on and I was wondering because I thought it was a bad sensor so I replaced it with one that I thought was good, but I dont think it turned out to be good. After I did that the lights were all yellow, now the brake warning lamp is Red only when I drive about 2 minutes then turns to red. Could this have something to do with the faulty sensor that I thought I replaced? I am trading it in Tomorrow and I dont want a MAJOR PROBLEM. I think it is a faulty sensor somewhere but why would it go red now?

Thanks