93CadillacOwner

I have a few questions that I'm hoping to get some help on.  I recently purchased a very low mileage (25,000 miles) 2006 Cadillac DTS that was very well maintained.  I have put 9000 miles on it with no troubles other than the stabilizer light will come on occasionally and then go off.  Last week when the temperatures here in Virginia hit around 100 degrees, I was making a turn onto the highway and the steering wheel seemed to shudder and I lost control of the vehicle for maybe 5 to 10 seconds.  The car also seemed to shut down.  I suspect that it may have been a computer failure.  Then the car became normal again and I have not encountered the problem since.  None of the error lights came on the dash.  Yesterday I called Cadillac inquiring about any recalls that may not have been repaired on this vehicle.  They told me that there were four (4) recalls on my vehicle but only one (for the ignition key/lock) would be attended to.  They said that the other three are "closed".  THe local Cadillac dealer who is going to do the ignition key fix said that would not have caused the steering/shut down problem that I had encountered.  So my questions are if any of you have heard of this type of problem before and do you have any advice on how to troubleshoot it?  I suspect that heat may have played a part in it, since it was such a ht day when it happened.