Can I use a computer memory unit with a 9 volt battery to maitain codes when I replace battery?

2003 PORSCHE BOXSTER
40,000 MILES
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RICKY ANNE
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My 03 boxster S 8 yr old battery needs replacement I have a auto computer memory unit that plugs into the cigarrette lighter. Will this retain codes or am I likely to fry something?
Oct 1, 2011 at 4:33 PM
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CARADIODOC
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That will work as long as the ignition switch doesn't have to be on for the lighter to work. If it does, you'll be asking that little battery to power all the things that are switched on by the ignition switch. That includes the radio which in itself will draw the battery's voltage down far enough to kill the memory circuits in various computers. I don't mean "kill" as in damage. I mean erase the stored codes and fuel trim data.

I use a small battery charger hooked right to ground and the positive battery cable, but you have to be careful the clamps don't pop off and the positive one doesn't hit anything metal on the body.

Happy to hear you understand the need to maintain voltage in the system while replacing the battery.
Oct 1, 2011 at 5:52 PM
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RICKY ANNE
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I checked and the lighter will work without key so I think I`m OK. Thanks for this great service.
Oct 1, 2011 at 6:07 PM
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