On the 955/957, the cornering lamp resides inside the headlight cluster ***'y. Exact bulb location varies depending on whether or not the car is equipped with Bi-Xenons. You will find full instructions in your owners manual on how to remove the headlamp to access each bulb.

This information for type of transient fault will reside in the module memory for 50 ignition cycles. It is possible to have the dealership interrogate the vehicle to obtain the fault code, along with the operating parameters at the time of the fault. That may prove useful at a later time, should the fault resurface.