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Old 07-01-2019, 04:32 PM
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Location: Dallas
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Security system/key fob issue

When I got my 2008 the guy gave me two fobs. One he said had a weak battery so I've always relied on the other one.

Then I was out of town and my wife tried to start the Jeep with the other fob. It got her to the store, but wouldn't start it again. Weird. She got my key and it ran fine.

Okay... weak fob.

Skip ahead couple of months. Wife goes to work with my fob in her purse (my bad - I asked her to carry my keys for me and forgot to get them back out of her purse). I've got to go to work, so I try that fob that doesn't work.

It starts the Jeep right up.

But then on Saturday it wouldn't start it.

Then today my "regular" key fob couldn't unlock the doors! But the unreliable fob could and could even start the Jeep.

WHAT IS GOING ON HERE? My big concern is that something is wrong with the Jeep not the fobs. Mostly I'm looking for others who had craziness with the keys and the fob and the security system. Thoughts and ideas?

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Old 07-01-2019, 05:11 PM   #2
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Join Date: Aug 2014
Location: S. Georgia
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The very first thing I would do is change the battery in both fobs if they operate the remote for the electric locks. They take the old trusty 3032 (same one that has been in computers and cameras for decades). I would not buy it a convenience or small volume store. I would get it at Wal-Mart or a store that has a high volume of those button batteries. If you have a key with no buttons on it (no electric door locks) then there is no battery inside the fob.

It could also be an issue with your Jeep battery. It would not hurt to take to to an auto store and have them do a load test on the Jeep battery. There are plenty of posts about "wonky" behavior with a weak main battery. In the old days when they got weak you got weak starts. Now if the voltage drops below a certain level, the electronics go wonky.

If it's not the battery in the fob, or the battery in the Jeep, then your fobs are dying. They are 11 years old by the way.

I had a 2006 Ram 2500 that had those same keys (no alarm system though). For years I had a friend who on occasion needed an HD pickup in his business, so he had my spare key. I later sold the truck to him as he needed it more than I did. On day while on a job site his fob would not unlock the doors so he unlocked them manually. It would start, but after a few seconds it would die. He bought new batteries (2 pack) but that did not help. He called me. (My key was now his spare) I had a meeting I had to go to shortly that evening, so his dad came by and got the spare key. That key worked. Both circuits in the fob were dead.

If you have the electric locks that is a separate system from the Sentry Key Immobilizer Module (SKIM) that keeps the Jeep from running. If it is the SKIM, the symptoms are the Jeep will start and after 2-3 seconds die. There is a red light in the instrument cluster over the right hand gauge. If you put the key in the ignition and turn it on, that light will light with all the other lights, but after a few seconds it will go out. If it does not go out, the chip in your key has died and it cannot be replaced, the entire fob/key needs to be replaced.

If you do not have electric locks, your fob has no buttons. You can either use that style of key, or the predecessor with is a plain oval head gray key. When my friend got back the next day he had one of the latter keys made. The one with the remote for the door locks is more expensive and he said he could unlock the doors with the key without any issue.

That plain key cost him $71 at a local locksmith. I don't know if the locksmith even had a key with the buttons. I got a quote from my dealer at the same time of $150 for that key. While you can buy the keys on line, have them cut and theoretically get them to work, I was never successful - I killed two keys trying (one mistake that key is locked out of the system).

After his experience, I went to that same locksmith and had a third key for my TJ made (for $71). When I bought it, it came with two keys. One said JEEP, so I assume it is an original. The other had the Chrysler Pentastar logo so I assume the PO had that one made at a dealer. They were both getting old, and I did not want to be down to one.

There are two oval head keys for predecessor vehicles - one has a black head and the other has a gray head. The gray head has the chip for the SKIM (which was an option until 2007) the black head is just a plain key and a $2 metal key will work in that vehicle. In case you are tempted, you cannot just unplug the SKIM module as the TIPM is looking for it.
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Old 07-02-2019, 09:14 AM
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Follow up: rgreen65's post was so helpful. pulled the fob apart and had a lot of gunk in there from the battery. ordered new fobs. think the issue is wonky fobs, not wonky jeep security system. thanks so much.
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