its def worth a visual check of the sensors on the pass side suspension arms front and rear. There is a little box with an arm and silver(when new) con rod with 2 rose joints that connect to wishbone.
On mine the arm had come out of the box. This is a ball joint that is a press fit. It wears and can also be pulled out by ceased rose joints, as mine was, as it could be seen hanging loose with the front wheel on full right lock while looking by the front pass door hinge.
If you have this problem you can try greaseing the ball joint and pressing it back into the box, but you may find the it only lasts a day up 2 before it falls off again and the warning returns. New one is 50 sobs from vx.
If the sensors are visually ok then you really need tech 2 as said. I would highly recommend The Boy for this, see his web link at the bottom of one of his posts. Or pm him, he has a couple of tech 2s dotted around the country with members who know their onions. Dont bother the dealer with it, as a rule they dont know what they are doing, esp with tech 2. Hth