This is very odd, your stations were erased? I replaced my battery in October. I took it out, went to O'Reilly's and came back. The car was without a batter for 1/2 hour.

I put the new one in, and my radio (Factory Infinity with NAV) had remembered all of it's presets! My Tach clock was at 12:00, and the clock in the radio was GONE, but the presets were all there. ODD.

To get the clock in the radio back, nothing worked. A few days later, I used the NAV and THAT brought the clock back.

I have had the radio out several times since then - it always remembers it's presets, but the clock goes away and only comes back if you use the Nav once.

I wonder about your radio now.