Once the batteries start to go, all sorts of strange things happen. First, I would replace both batteries. Then see what happens.

 

I got three codes:

P0514 - BAT temperature sensor rationality.
P2509 - Powerdown Data Lost Error.
P1755 - don't know, not showing on the code list.

I'm not sure what all that means but that's a handy trick. Any help would be appreciated. I speculate it's low batteries, however.

 

That 2509 is what mine threw when it needed new batteries. Although it would start up it would do some weird stuff like the gauges would click and jump. Random stuff like my overhead and fog lights would shut off or reset themselves.

I've read the dealer sells pretty affordable size 65 batteries.

 

Yep. Weird things happen......

I found two Optima 34/78 batteries at Advance Auto for $162 each but since I bought two I asked for a discount and the salesman knocked off 15%!! Freakin' great deal - it was $48 savings so I got the batteries for about $138 each. Everything working good now - no more freaky gauges, check engine light or tranny irregularities. Oh, the red top Optimas look good, too.

Thanks!!

 

I had a yellow top Optima in my wife's Tahoe. I only bought it because the factory battery croaked late at night and Auto Zone was the closest parts store still open. Extremely unimpressive. I wish I would have saved my money. It didn't last as long as the factory battery. I replaced it with one of the Kirkland batteries from Costco. Always had good luck with them, manufactured by Johnson Controls, and priced very well. No more yellow tops for me.

Also, I read the last battery tests from CR, and they listed the Kirkland batteries as being best buys. I don't work for Costco or Johnson Controls.

 

A little piece of interesting info for you guys.
I did a service call at Johnson Controls here in SoCal a couple of years ago. I program industrial machines and they needed some changes on the battery washer/tester machine. What I saw there was most of the brands of batteries on the same line, including Optima. They are produced in the plant and shipped to the distributors. They are all built and tested to individual standards, the highest standards I saw was the Optima. I did not see the standards for all of the brands but all batteries are very similar.
Just thought you-all would like to know.

PS My mechanic friend likes Interstate, which are made at Johnson Controls.

 

I think I had to delete the stored codes to get rid of some of the weird stuff after switching batteries, just FYI.

Glad to hear it worked out.