Need some opinions/answers

Tiny
MMPRINCE4000
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  • ALL OTHER MAKES ALL OTHER MODELS
On newer cars, is it necessary to supply aux. Power to PCM while changing batteries?

I have seen a couple cars that when battery was removed, the radio stopped working, some techs say you need to plug a small battery into diagnostic link to keep radio powered during battery change.

Any opinions. Paul
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Sunday, January 3rd, 2010 AT 2:28 PM

9 Replies

Tiny
DAVE H
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Hey Paul.

I use a power/memory saver which is simply plugged into the cars cigarette lighter .. I use it everytime I remove/replace battery !! saves all memory setting's and also KAM in PCM/ECU .. so no more drive cycles or complaints from customers over their radio settings/codes .. LOL


http://www.2carpros.com/forum/automotive_pictures/266999_AAA2_942.png

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Sunday, January 3rd, 2010 AT 3:23 PM
Tiny
BLACKOP555
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Small and cheap device. Right in the cigarette lighter as stated by mr dave.

I wouldnt add power to the pcm personally sounds to be a good way to fry a computer!

Its not necessary but it saves the hassle of the relearn procedures and having to reset radio and theft system. And happier customer with no comebacks.
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Sunday, January 3rd, 2010 AT 3:40 PM
Tiny
MMPRINCE4000
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Thanks guys, I wanted your opinion that if you did not use a memory saver, would that cause the radio not to work? Thanks. Paul
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Monday, January 4th, 2010 AT 2:15 PM
Tiny
RASMATAZ
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Prince-just use another battery parallel to the battery being remove-seal the positive cable/clamp away from ground from the old battery-just be extra careful when swapping over-

Or just go thru the Cig lighter with the other suggestions-
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Thursday, January 7th, 2010 AT 5:42 AM
Tiny
KHLOW2008
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When memory is lost, most radios needs a reset code so that must be the reason the radio does not work.

The system mentioned was started in the late nineties by Merc and has since been scrapped at our end. After battery removal, the PCM has to be reset in order to start vehicle and that means getting the vehicle towed to the dealership if the battery were to be removed.

Hope I am talking about the same thing.

I agree about the cigar lighter plug in but as mentioned, take care not to short the battery terminals. Don't forget to ensure the cigar lighter plug is functional before attepmpting it, you might be in for a surprise.
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Thursday, January 7th, 2010 AT 5:42 PM
Tiny
BMRFIXIT
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Cigarette lighter /memory saver not a bad idea
but not all model have the lighter wired for power at all times and some require key on
check 1st
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Friday, January 8th, 2010 AT 12:56 AM
Tiny
MMPRINCE4000
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Good point by BMR, Toyota's cigarette lighter only is on when ign. Is on.
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Friday, January 8th, 2010 AT 1:18 PM
Tiny
DAVE H
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It does not matter whether the cigarette lighter is powered up or not (ign off or on) the power/memory saver, sends minimal voltage too radio and PCM/ECU circuits to store the memory's .. you can buy gadgets to plug into the cigarette lighter that let you boost/jump start the vehicle !! You could also use a jump box on vehicles fitted with seperate jump points from battery !!


http://www.2carpros.com/forum/automotive_pictures/266999_AAA2_947.png

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Saturday, January 9th, 2010 AT 3:10 AM
Tiny
MMPRINCE4000
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Thanks Dave and everyone else. Paul
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Saturday, January 9th, 2010 AT 1:19 PM

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