Nope, just unlocking the driver side door with the key itself and an alarm starts going off.

 

Have you tried disconnecting the battery to rest the system? I assume this just started to happen. What happens when you use the fob button to unlock the door? Does the alarm go off when open the door?

Did you get a new key? Is this a new car to you? Did you have to jump the batery or user a charger on it recently?

 

Pretty much no to all of the above. Had the car for 5 years, same key fob. Can't remotely unlock the doors, that's how this saga started. I can only get into the car by using the key to manually unlock the driver side door. I'm gonna try to disconnect the battery tomorrow. I tried this reprogramming procedure today to no avail.

 

OK The programming ONLY works if you have a mew key. Try the battery and let it stay off for a couple of minutes. You may jear the alarm go off so don't be concerned. If that does NOT work, the module that controls that is in the trunk on the right side under the floor. Check that for water/condensation or a loose connection.

Do you have a repair manual if NOT there is one on line? keep us posted on the vattery issue.

One more thing -- Change the bateries in the FOB before you do the battery trick.

 

Gonna try the car batter disconnect tomorrow, the fob has two brand new batteries in it now.

 

Sorry for the piece meal approach BUT do you have a spare key? If so have you tried it?

 

Unfortunately I don't have a spare. On the bright side after disconnecting the battery and doing the key reprogram everything seems to be working just fine now. I think the key fob batteries were dead long enough to erase the memory or whatever. I usually only drive every couple of weeks or so.


Once again this forum saved hundreds of dollars compared to having it towed to a dealership to be looked at. SOOO thankful I found this site!!!


Thanks to all,
Jeff

 

Thanks so much - changed the battery in the key fob and it stopped working. I could not believe it was as simple as that but it worked!

 

Even though this is an old thread, I would like to express my gratitude for this info on key coding and also to Rob at Needswings.com for supplying my beautiful new and working key fob and saving me real bucks - so I can afford to change the steering stabilizer, buy new SRT6 luggage and change the intercooler pump without getting ripped off by mechanics who would swap parts and probably never find the problem.

Pretty soon, I'll have a like new car inside and out. Thanks again so much to the operators, volunteers, ancient and current posters for saving me untold heartache, time and expense getting the car back to pristine condition!! Is there a tip jar here?

 

Old thread, but always worthwhile information. Looking back through the whole thread I note that a I entered replies two years ago with this info, but worth typing again.

There are at least TWO distinct functions served by our Crossfire key-combined-with-fob. One is to remotely unlock (lock) doors and rear lock, simultaneously disabling (enabling) alarm. This Remote Keyless Entry (RKE) is done by a radio TRANSMITTER (only) in the fob, which depends on the fob battery to work. When the battery in the fob is replaced, or car battery is disconnected for a time, this match must be re-synced. But how to do a RKE / alarm sync is described in your Owners Manual (and earlier in this thread).

The other distinct function, very important to me (and others), is to START and run the motor, and the car. This does NOT depend on the fob battery at all. Instead requires a match between electronics in the car and a code ONE TIME BURNED into a distinct transponder chip glued into the fob. This transponder chip is energized by radio frequency power coming from an antenna around the key cylinder in the dash (not by the fob battery), and responds to that antenna with the secret code shared with the in-car security module, which in turn tells the engine electronics "OK, start and run."

U.S. key sellers and dealers cannot wrap their heads around the fact that the transponder / immobilizer chip in the Crossfire (and related Mercedes) fob is, by all credible accounts, ONE TIME programmable. So once the transponder chip in the fob (not the same as or on the RKE circuit board) is married to a car module, it is stuck, forever, with THAT car. Dealers for the Detroit 3 (including Chrysler) have never dealt with keys as restrictive as this, requiring new keys be ordered only from a factory controlled shop. But that is our Crossfire reality.

Therefore any used already-been-programmed Crossfire fobs on eBay are useful only for the plastic case, and for an RKE circuit board. Some eBay remote sellers don't understand this, believe that the immobilizer chip can be re-flashed and reused, others are just being dishonest. If you have a working chip and metal blade from an old fob for your car, those can be transferred to a used fob, and all is good. Or you might buy a new case (with uncut blade) from China for less than $10, then do the chip and blade transfer.

Otherwise to have a functional (start the car) key and fob you must go through a dealer (or NeedsWings), supply your VIN, pay at least $150, wait a week or so from Texas (or Germany), and get a nice new cut-for-your-car and immobilizer-chip-matched fob. Which still needs the 10 second mating to the car for RKE button functions (don't pay a dealership for this).

Does that make sense?

Clint

 

Makes perfect sense. Thanks again!

 

Yep, Clint has it right. i thought I'd pick up a used mBz fob on ebay and look for a new key to be cut and quickly discovered that was a no go.
I ordered a new key through Capistrano Chrysler a few years back and they charged $108 tax included.
It pays to make a few calls and shop around.

 

This worked to perfection! Thanks to the OP!

 

While at the Amelia Island Concours this past weekend, I gave my spare key fob to a friend to use. I knew the batteries were dead in it, but I figured he could just use the key to get in the car... which he did. He didn't use it to start the car. When I returned to the car around midnight and tried to use my good key fob.... NOTHING. So I unlocked the car using the key, and when I opened the door, the alarm went off for 30 seconds. I put the key in the switch and started the car, but it immediately shut off. Did that twice, then the engine wouldn't turn over at all.
Good thing for mobile Internet devices, as we were able to visit this site and figure out a solution.
1. Bought new batteries for both key fobs and installed
2. Disconnected car battery for a couple of minutes
3. Reprogrammed key fob using OP's procedure.
4. Started car and problem solved.
Thank you!!
I only hope the folks who were trying to sleep weren't awakened too often when the car alarm kept going off while trying to figure this out. :-/

 

I have two keys, with both I have changed the outer cases. Keys A and B worked with the car.

Just recently tried spare key B. The car turns over fires but will not stay running. Then after a couple of almost starts, the electricity/access cuts out. I take the battery off, wait a bit and use Key A, it works fine.

I replaced the batteries in Key B, went through reprogramming sequence, and it still gives false starts where car fires, but will not stay running, then shuts down. If I take battery off, and use key A it works fine.
What do you think I am doing wrong or is there a step I am missing?

Thanks for any suggestions.
Kevin

 

I think you lost or damaged the chip in key B.

 

HI All .Greeting from singapore

Really need some help on this ,

I just got my 05 crossfire convertible last month ..sadly only come with 1 remote key .
chrysler singapore quoted me 1200 for a pair ...that's crazy !

anyone can advise me what alternative can i do to get another ? tks much

 

Hi!
I own a 2004 XF in Europe.... Over there a replacement key is 250 Euro ($320)

As I also live in Chicago I thought of getting the key here cheaper... I went to the Chrysler dealer in Orland Park /IL and the want to charge $ 395 !!!!
I asked them if they would take to many drugs and left....

Can anybody tell me where to still get a better price...

I do not really need it urgetly but i have only one key and it is alays good to have a spare...

Thank you,
Werner

 

Most of us go here...

Link: Key OEM Replacement

 

Worked like a charm, battery went dead program was lost did like you said worked with in 15 seconds thank you