I have a nissan 200sx 1996. My check engine light keeps coming on with the battery and brake light. The code was for the egr and I had had the parts replaced with new and yet all 3 lights are back on again. I am wondering if it could have something to do with the fact that the last time I check the codes myself using the diagnostic mode on the ecm I turned it too far so it now does not work. Can that be repaired also?