I saw codes showing undervoltage and not even 1 for overvoltage.
If there is overvoltage condition the transmission computer will switch to safe mode and there will be a definitely clear code showing overvoltage.

A recommendation: check for codes again in a week. I had an intermittent water pump not reaching commanded speed for about 6 months. Doesn't cause a MIL. Gave up the ghost- seized. Stranded and 1st tow bill in over 20 years. Those codes may be a warning.

Very interesting. I hadn't come across such in my reading. That, with the general ignorance about batteries and charging, might explain some mysterious flurries of error codes.

I really do think that most integrated circuits have input voltage regulators.

They all do. But the transmission solenoids dont have voltage regulators. At 3-4 volts or more over nominal the solenoids characteristics will change significantly.
I have had 2 N62 powered cars recently that will have similar symptoms. All is good at idle and low RPM. Once the RPM jump over ~2000 the trnsmission will go in safe mode. Having ISTA connected while driving I find the voltage to reach 18-19v. Overvoltage codes were to be found in most modules,7-8 at least.

Got the car back today, overheating issue fixed. New water pump and changed the thermostat any way, radiator flushed, oil changed, battery reprogrammed and all codes clear , and coding of some comfort features all for $1300 not bad.

After reprogramming the battery the alternator started behaving normal. Car went back to 24 mpg highway.

Thanks all for your input.

If you are in NJ I recommend Vanos Motorsports in Carlstedt, N.J. to do the job.

http://i666.photobucket.com/albums/v...psprczunao.jpg

http://i666.photobucket.com/albums/v...psicwacakd.jpg

http://i666.photobucket.com/albums/v...pswypwhtrv.jpg

http://i666.photobucket.com/albums/v...psuhnmugfl.jpg

I would keep an eye on your oil level AND oil quality.

If in 500 miles you see nothing going on between coolant and oil, you dodged a bullet.

Nice shout out to Vanos Motorsports.

I definitely will. SAV is driving like brand new.