When putting the truck in drive the automatic transmission check light and service engine light comes on, the truck also appears to drag upon take off and feels if it skips or shifts even though it an automatic transmission while driving. I have had a new transmission control valve put on but the problem is still there. this beappening after i installed a tow hitch, tow harness and brake contol towing unit on the truck. does this has anything to do with the body control module sub harness or a brake control unit installation? please help.

Cars & Trucks - Nissan - Titan - 2005 Nissan Titan