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How long should a FOB battery last for a Jeep ?

I have this 2011 Grand Cherokee with keyless entry and ignition system.

It works great and makes it easy to not need to get my keys out of my packet however, this last saturday while shopping, I came out in the lot to get back in my car and I couldn't open the door with out using the emergency key in the FOB. I did that however, the instructions in the printed user manual instructs you to use this emergency key for both getting in the car and starting it as well, that just isn't so :)

After whipping out my phone which has the printed PDF full manual on it, It words it a lot differently, clearly indicating that you need to use the tip of the FOB as the key with the emergency key inserted with in the FOB as normal. WIth that, I was able to start the Jeep and be on my way..

But this is the issue, I have owned this Jeep for less than a year, I bought it new obviously. I checked the manual for the cell type which indicates using a CR2023 button cell, ok. Well, I had some Cr2032 cells around which last longer. So I commence to opening the FOB and what I find in there is, a "CR2032" already installed? Well, why does the manual indicate using a "CR2023" with no other options and that is not what they are installing in there?

Shouldn't that cell last much longer than 10 months of use?

I did some online research and it seems that this device likes to transmits a lot when ever I am in the car using the ACC mode, which I do a lot, and maybe even when the car is operating. I don't know if this contributes to the drain or not?

I will say this however, there is a very neat system in there, it appears that real hardware key must be inserted in the FOB before the FOB will work as a key itself. By looking at it, the tip of the real key is acting as a transmittion line or E-line because there is a coil that is wrapped around the key up on the neck of it inside. I mean, the coil is hollow to allow the key to slide through it. I know the FOB does not work with out the real key inserted in it. Just an interesting observation.

I just wonder what I'll do when the transponder in the car decides to stop working! :)

Jamie

Reply to
Jamie
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"Jamie" wrote in message news:EF2jr.2432$ snipped-for-privacy@newsfe07.iad...

Just Hot wire it.

Cheers

Reply to
Martin Riddle

The CR2023 cells used to come from Japan. Now they come from China. Japanese cells to last 4 to 6 years. You would replace them once as you owned the vehicle. Chinese cells last 2 to 3 years.

My ride is 6 years old, so I still have a real key in addition to the fob. I'm not looking forward to "new technology" if it can leave me locked out.

Reply to
miso

Getting in is one thing.. my car can't be started unless the correct encrypted key is present- the ECU won't allow fuel to flow etc. It's got a rechargable battery inside the fob that is charged while you are driving.

Best regards, Spehro Pefhany

--
"it's the network..."                          "The Journey is the reward"
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Reply to
Spehro Pefhany

Make sure you are locked inside and there is NO way to get out and hope you have a medical condition as well.. worth a few million dollars or so..

Reply to
Robert Baer

On a sunny day (Mon, 16 Apr 2012 20:26:35 -0400) it happened Jamie wrote in :

I once smashed the side window of my Mustang when I accidently closed the door with the key still in the lock.

Reply to
Jan Panteltje

Then you are really F***ed. I know someone who forgot the lights on a sedan. Unfortunately that car had the battery in the trunk. Now how to open the trunk when the locks are electric and only the front door can be opened with the FOB? He had to crawl over the front seats, pull the rear seats down and somehow reach into the trunk. All in all it took 5 hours to get the car going again. Never ever buy a car with such a system!

--
Failure does not prove something is impossible, failure simply
indicates you are not using the right tools...
nico@nctdevpuntnl (punt=.)
--------------------------------------------------------------
Reply to
Nico Coesel

Such a system is standard on every car for the last 15 years or so.

--
Failure does not prove something is impossible, failure simply
indicates you are not using the right tools...
nico@nctdevpuntnl (punt=.)
--------------------------------------------------------------
Reply to
Nico Coesel

They've been required in the UK for more than 15 years, in Canada only since 2007, and AFAIUI, are currently NOT legally required under US atandards which means they may be standard, optional, aftermarket or just not present).

Reply to
Spehro Pefhany

Robert Baer wrote in news:LI6dnWPNubuQjhDSnZ2dnUVZ snipped-for-privacy@posted.localnet:

is there such a cell as a CR2023? maybe its a typo and it's supposed to be CR2032.

if it's in your pocket,it might be getting activated when you're not near your car,and every activation uses some power.

the "real hardware key" probably has an RFID chip in it. Without that,the car won't recognize the FOB.

--
Jim Yanik
jyanik
at
localnet
dot com
Reply to
Jim Yanik

In the US, the keys had/have a transponder, but they don't have to be powered. That is all I had in my 2001 Benz, which certainly fits your time frame.

I forget when key "stayed in your pocket" started. 2008?

Reply to
miso

I have two keys, one with remote door lock/unlock and one without, only the remote has a battery so the encryption must be passive like rfid

-Lasse

Reply to
langwadt

for what ever it's worth, I can put the hardware key in the hole where the FOB is to be, there is no key tumbler there however, it does detect something there but reports a "Damaged Key", If I place my pin in that hole, it too gets detected and reports a "Damaged Key". If I put the FOB in the hole with no hardware key, it knows nothing.. If I slip the hardware key into the FOB then it all comes to life.

The only think I have not done is inserted a small screw driver the length of the key in the FOB in place of the key to see if that too will work.

When I examine the inside, it's obvious what is going on, there is no electronics that I can see at the tip where the FOB is inserted. The only item that is sitting there is the tip of the hardware key. However, this key goes through a rather large coil with lots of turns on it sitting back on the circuit board. This is the only place where I can see the FOB actually getting any DATA or sending it. So the hardware key itself looks like it is acting as a E-line/G-line. or something on the order of surface radiation much like a tesla coil would do.

As for the key itself (hardware key) having an RDID tag in it, I don't think so. This key is like 97% all metal with a very, very thin tip of plastic on it where the ring goes through.

I think the FOB has the RFID in it and the key is used as the E-line to link it to the trasponder.

My tumbler on the door feels like a real hardware lever inside on the lock pin.

Jamie

Reply to
Jamie

As long as you aren't named 'Maynard'.

--
You can't have a sense of humor, if you have no sense.
Reply to
Michael A. Terrell

I don't think this is exactly relevant to your situation, but as a FYI, the ignitions that accepted physical keys had both RFID and a tamper sensor. I've had two cars with that scheme. You get a spare key that can only be used to open the door. If you put it in the ignition, it will trip the tamper sensor, just like the guy trying to start your car with a screwdriver.

One problem with these tamper sensors is you could have the proper key in use, but have a lot of junk on your key ring, and if bounced enough, trip the tamper sensor. It may take a while for the perfect storm to happen, but it has happened.

Every bit of anti-theft hardware they put on a car is something that could strand you if it fails. Even the transmission lockout switch can ruin your day.

Reply to
miso

Difficult if it's all CAN bus ;-(

-- "For a successful technology, reality must take precedence over public relations, for nature cannot be fooled." (Richard Feynman)

Reply to
Fred Abse

"FOB battery"

Is that different from a CIF battery?

:-)

-- "For a successful technology, reality must take precedence over public relations, for nature cannot be fooled." (Richard Feynman)

Reply to
Fred Abse

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