Has anyone used the little computer assist tool (9 V bat. one end-cigarette lighter plug on the other) to retain the K.A.M. memory of their ECM & radio stgs. while disconnecting the battery for post cleaning or battery replacement?

I've done it on U.S. cars which have a direct line to the battery connections, through the lighter, with the key OFF. With these M/B setups you must have the key in the acc. pos. to have access to the electrics on the car. I'm wondering if a spike will occur with the 9 V bat. plugged in & the key being rotated to the acc. pos.? Just running a volt meter across the bat.,without the 9 V tool connected, & turning the key to acc., there's only a .15 drop due to the digital dash & light behind the radio on-off illum. No prob. there for the 9 V tool to handle while the bat. is disconnected. I keep the interior lights off for this process. My concern is poss. taking some out (in a very expensive way) by having to partially power the system up in the acc. pos. Thks for the help.

Crossfireone

 

Easy way to do this is to hook up a lower amperage battery charger to the system (2 amp is plenty) in place of the battery, without disconnecting the system from power. i.e. - hook up the charger to the battery cables and THEN disconnect the ground from the battery.

Hope that helps.