MikeDC

Will the auxiliary battery allow the radio to retain the radio code when I disconnect the main battery?

John CC

Mine remembered presets, and I think even the clock (not sure). No code was required. (Which is good since I don't know where to find it!)

calder-cay

I've done the opposite... replaced the Aux battery with no ill affects. But the rumor is the Aux is for ECO mode support (during stop start conditions).

Personally, if I were worried about various saved settings for main battery replacement, I'd simply hook up a trickle charger to the positive feed (charge) connector, and negative to the ground point ... swap battery, and be done.

John CC

My GLK250 has the battery but no Eco start/stop. I think it's somehow tied to the electronic gear shift.

MBKLUE

I've had the main and aux. battery disconnected at the same time with no problems or resets etc. needed after reconnection.

2014 350 Gasser.

Silver Shadow

No problem disconnecting the battery on my 2010 gas, no aux battery.

techrick

Yes start/stop was introduced in 2013. Just tore our 2012 looking for aux batt to finally discover there is none.