One problem related to alternator/generator/regulator has been reported for the 2006 Cadillac CTS. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2006 Cadillac CTS based on all problems reported for the 2006 CTS.
While returning from a trip, the engine shut off and all the power in the car was gone, while driving (in motion). We had been driving approximately 1. 5hrs. We were going about 65mph, when the radio and ac went off. There was a message that said something about "battery reserve" (?????) I turned the radio and air back on. Immediately after, "service brake assist" message, then entire dashboard (including speedometer) goes dead. Car shuts off and immediately decelerates. Fortunately, we were in the slow lane already and could get out of quickly moving traffic (and the cars behind us could swerve into the other lane to avoid hitting us). On the side of the road, all power was still lost and could not remove the key from ignition. Attempted to "jump off", which restored power to remove the key. But vehicle would not start and ultimately had it towed. Dealer said motor was locked but didn't know (or immediately care) why. After I prodded the service manager, the technician called to say it was the alternator belt that was locked, causing the motor to be locked. With all of the ignition switch issues that I have read about the last 2 days, I am concerned that neither of those are the cause, but a result. My key "fix" lasted about 2 days. Although mentioned, the key was not "fixed" on the next visit.