traction lights come on/check engine light always on. car feels like it sways sometimes on the road.

we drove 8,200 miles to alaska. the last 2k miles were awful. mostly dirt and full of pot holes. we had to catch a ferry ride and then the problems began. once we got off the ferry the check engine light came on as well as the anti slip light and traction light with a wrench next to it. the check engine light is always on, and the other two traction lights come on periodically. about a week ago the check engine light went away on it's own for the day then came back on. i unplugged the battery and a few days later the check engine light came back on. the steering seems a little funny only on certain roads the have ruts. it feels like you're driving straight but the car leans to the left or right. what could the problem be?