How long should a FOB battery last for a Jeep ?

[Jamie]

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

 

[Martin Riddle]

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

Just Hot wire it.

Cheers

 

[miso]

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.

 

[Spehro Pefhany]

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.

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

 

[Nico Coesel]

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..

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!

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!

 

[Nico Coesel]

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

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

 

[Spehro Pefhany]

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

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).

 

[miso]

Getting in is one thing.. my car can't be started unless the correct

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

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?

 

[Jamie]

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

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

 

[miso]

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.

 

[Fred Abse]

Just Hot wire it.

Difficult if it's all CAN bus ;-(

 

[Fred Abse]

On Mon, 16 Apr 2012 20:26:35 -0400, Jamie wrote:


"FOB battery"

Is that different from a CIF battery?