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Discussion Starter #1
've got a bit of a problem here.

i have had the battery disconnected on my JK for quite a while (a couple weeks) while building a dual battery tray. well, today i wired everything back up (with an isolator) and went to start my jeep and it won't start. everything else electrical in the jeep works (brake lights, headlights, interior lights, power windows, radio, yada, yada) but it acts like the starter isn't getting power. i've double and triple checked all wiring, relays and fuses.

also, the key fob's (power lock remotes) won't lock or unlock the doors. the doors lock and unlock normally with the switch built-in to the doors, but the remotes don't work (i've tried both of them).

i called a dealership, and they told me that if the battery is disconnected for more than 24 hours, that the computer dumps all of its memory and has to be re-programmed.

does this sound right? the reason i ended up calling a dealer was because i wondered if there was some kind of theft-prevention program that was keeping it from starting.

if this is really the problem, then this is a bunch of B.S.!!!! what are you supposed to do if you want to store your jeep for a while (like when you are deployed to iraq or something) so you disconnect your battery so it doesn't get drained?

has anyone else ran into this? or does the dealer's explanation sound correct, or is there some theft prevention program that is keeping me from starting it?
 

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is it turning over???? Sounds like the battery is weak. I think the dealer is full of crap.
 

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is it turning over???? Sounds like the battery is weak. I think the dealer is full of crap.
X2 I really can't believe that any vehicle would need reprogramming if the battery was disconnected for 24 hrs.

If the batteries are fully charged, I'd start looking at what you've done, and check that there isn't a wire lying around somewhere that should be connected.
 

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Discussion Starter #4 (Edited)
the batteries are both brand new - an optima yellow top and a red top in a dual battery tray underhood. so, i know the batteries aren't weak.

it doesn't turn over, when trying to start it.

i am 100% sure all wires are connected. everything else in the vehicle works, it just won't start, and the key fob (sentry key) won't unlock or lock the doors. i even tried removing the isolator and wiring it back up as a single battery system without the isolator, just like stock, and it still won't start.

neither one of my key remotes work (neither one will lock or unlock the doors). this is what made me think there might be some kind of theft prevention program that had activated. i even replaced the batteries in both of them.
 

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I agree with the others. I have never heard of anythning on the ECU needing reprogrmed aftetr being disconnected.

I have heard of issues due to aftermarket alarms. I assume you would have mentioned that initially but, do you have an aftermarket alarm?

Disconnnecting the battery should only reset "learned" data. such as shift points and you may possibly fail an emmisons test if your stte uses an obdii check but the ecu is flash memory. The lock code for the key is progamed into each ecu's code which does not go away when disconnected.

you may have blown a fuse??
 

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i HAVE HAD MINE DISCONNECTED FOR 3 days before and did not have an issue. I would check fuse's
 

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the batteries are both brand new - an optima yellow top and a red top in a dual battery tray underhood.
I've had my battery disconnected for a week with no problems after.
Please post up some pics of your underhood dual batt tray. Would love to see how you did that one.
 

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Discussion Starter #8
i trailer'd it to the dealer. they are going to look at it tuesday. the guy i talked to seemed pretty confident that the computer had to be reprogrammed, especially after i told him that the key FOB's wouldn't lock or unlock the doors.

remember, i had mine disconnected for a few weeks. i don't know. i am pretty sure all the wires and grounds are good. i checked every fuse and they were all good.

i even wired it back up with only one battery and nothing else (just like stock) and had the same results.

I've had my battery disconnected for a week with no problems after.
Please post up some pics of your underhood dual batt tray. Would love to see how you did that one.
if the dealer gets the computer/not starting thing situated on tuesday and gets it running, i'll get some pics of the final product. i have some pics of it in different build stages that i'll try to get up this week too.
 

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FWIW After having had three Optima batteries go bad on me I no longer use them. I've heard of many them going bad, so it is possible you have bad batteries.
 

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I have an Optima yellow top, AND, I had my JK in lockup last winter when I was in Maine for 58 days, battery disconnected...no problems here...I am of the opinion that with all the backyard modifying of the JK by dilitantes, there comes with it, the numerous complaints...whether it be electrical, lifts, gigantic tires, spacers, etc., etc., ad nauseum...everything I have done is with a purpose, and with simplicity...I have yet to have any problems....my dos centavos.
 
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FWIW After having had three Optima batteries go bad on me I no longer use them. I've heard of many them going bad, so it is possible you have bad batteries.
I've given up on the Optima Yellow Tops, too. I just got tired of paying the extremely high price and finding they really don't last that long. I have a dual battery setup in my XJ with two yellow tops and I end up replacing one a year at $200 a pop. No more.

Back to the original post - do you think you might have shorted something out while you were doing the modifications and "blown" something in the ECU?
 

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Discussion Starter #13
Have you charged them?
no, i didn't charge them since they are brand new. i don't consider bad batteries to be the problem, since everything that runs off of the batteries still works - interior lights, radio, headlights, driving lights, etc...

Back to the original post - do you think you might have shorted something out while you were doing the modifications and "blown" something in the ECU?
i wouldn't think so, but i guess it's possible.

the odd thing about the whole situation is that everything electrical works - all except it won't start (doesn't turn over or even make a sound) and the key FOB's won't lock or unlock the doors (the doors will still lock and unlock by pushing the electric lock button built-in to the doors though.)
 

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I just posted my problem after useing the panic button. I had the same thing, the door remote would not work and the engine will not turn. disconnected the battery for 5 minute and the doors would finnaly lock with the remote but engine will not turn. Its at the dealers know.
 
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