Sounds like border line batteries to me. Better take care of them before they take care of your ficm. I'll bet if you take that reading again with the batteries seperated one of them will be considerably lower than the other and dragging it down which is why you change batteries together. Also a good idea to look at the build dates and get two that match.

 

Well the bad one will be under warranty, but I don't really have the extra cash to throw down on a new one "just because".

 

It's not "just because" It's a proven fact. However if you don't have the money then you have no choice in the matter.

 

I didn't mean it like it was just hear-say, I just meant that I've got stuff ranking way higher on the bill list to justify replacing a good battery.

 

I just had the same thing happen to me....

My truck would barely turn over....to the point of showing low voltage to all 8 injectors or whatever.

Replaced both batteries and man my truck starts great now, tested FICM and its good. Hopefully no further damage was done.

But...if its under warranty, go replace it, before it does wipe out your FICM