I would start by carefully checking the size of the wheels and tires. Mismatches (front to back or side to side) or way oversized can cause ESP errors. Of course, it's normal for the ESP light to come on momentarily if one wheel looses traction such as drifting off onto the shoulder (gravel).
OBD scanners are primarily for emission control devices and are handy to have. However, even used SDS's cost more than you paid for the car!
