rlme36

This could be the trick for those that need to swap out a battery and still maintain drivability codes. don't own it myself, but I've wasted larger money on dumber things.

rob

E-Z RED (EZRMS4000)

Super Automotive Presets & Computer Memory Saver
http://www.tooltopia.com/ez-red-ms4000.aspx

Slow Guy

Another option is the 9v battery that plugs into the cigarette lighter tool, much cheaper. I've never used it, for some reason I don't have to reset the readiness flags when I remove the battery, they stay set.

99er

What's the 9v battery trick? Plug one of these in and you can change the battery without losing codes?

http://www.amazon.com/CTA-Tools-3002-Computer-Memory/dp/B000GKD5Q0

Slow Guy

Something like , there are several others. Like I said, I haven't used one as mine stay set, hopefully someone that has used them will chime in.

NC TRACKRAT

Yep, a 9V battery with a cigarette plug will do the trick....or, if you have a spare 12v. battery of any size in the garage, hook it up to the cigarette lighter with your Battery Tender leads. Just be sure to get the polarity right.

il pirata

Or if you also need a battery maintainer get the CTEK 7002 which has a supply mode as well ( most likely other brands do this also). Usually about $105 or so if you shop around.

dmwallace

Can the Porsche Charge-o-Mat battery maintainer be used to keep voltage to the engine computer while changing the battery?