Key Fob Programming!!
 

Can anyone on the forum members help me with this one?

When I brought my 75 it only had one key!!

I had brought the car a few days before I went on a 3 week holiday, on returning, I went to start thew car and the battery was dead, no problem I went to a local motor factors and brought a replacement battery, I thought that would be the end of the problem, but I had a "engine immobilized" warning light on the IPK.

The long and short of it all, I had to get a replacement key from a ex-dealer, which is working fine.

Whilst I was down with Ralph's @ EMS this week having a new speedo head fitted and a session on the T4 making a few adjustments, I took the original key that opens the doors on the plip buttons and fits the the barrel but the immobilizer part is not recognized on the ECU or whatever it connects to, I was told that you should be able to reprogram they key, but they told me it can not be done as I do not have the bar code that relates to the key, I was under the impression that the T4 should be able to read the code from the key? and the T4 is only for programming the opening and closing of the doors using the remote?

I would like get the original key working again as a spare, does anyone know if it is possible to get the immobilizer part of the key reprogrammed without the bar code or if you could get the bar code from anywhere?

Perhaps Keith, Lates or anyone that knows about the T4 might be able to answer this one?

Regards
Tony

You do require the bar code or original Information that came with key I'm afraid.

The ECU needs the barcode information to link to the key. Without it it's a useless paperweight I'm afraid regardless of what most eBay sellers state.

Many thanks for the info John,

You might be able to answer my next question in that case, is it possible to override the immobilizer system, I have a seen threads on the "other side" that you can?

I have a CAT1 Clifford alarm fitted so I do not need the original alarm system or immobilizer working.

Regards
Tony

Thats like asking if you can open the bonnet when you have a broken release mechanism etc.. We are not allowed to discuss it on this forum due to the potential for abuse.

I'd recomend going to an alarm specialist and getting it done by the professionals.

Or go to Croydon and leave the windows open. Either way the end result is the same. :lol:

Steve,

I was not asking for information about disarming the immobilizer, just if it is possible!!!



Regards
Tony

From what I understand, if you fit new batteries to the keyfob, you then stand near the car and press the fob button 4 times. That should reset it.

With a T4 (laptop) you can read the numbers of any key that has been used previously. i.e. when my mech was adding my new key he found two numbers already entered, but not knowing which was for the existing key he did not cancell either of them, he just added the numbers from my new key, (a plastic label was attached to my new key with a bar code on it) making a total of three key numbers..

Hope that helps a bit.. :shrug:

NOTE--- the new key cost me £152. And still had to be "registered" in the cars ecu (?).. :mad:
.

The immobiliser is nothing to do with the battery in the keyfob, buttons or barcode, they are for the remote locking.
The immobiliser is a passive chip in the keyfob and is 'read' by the coil round the lock.

A new key is supplied with the chip already programmed to one of the codes held in the immobiliser ECU, the record of them is held by BMW in Germany.

MMM, my original key must still be registered on the ECU because I can still open and lock the car, it just the immobilizer part that's not working, I know there is a chip on the inside of the key fob, and that is what seems to be the problem, I don't know how this is programmed in the first place, its just very strange how after the cars battery went flat, the immobilizer chip could not be read by the ECU after a car battery replacement.

surely if the original key has already been used before the cars battery went dead, he will not need a barcode as the key should already be registered with the ecu,
if the original key was fine before cars battery went dead and then he purchased a new key , surely both keys should now work?

Ok let me try another route,

If I brought a "reader" collar that sits around the steering barrel and two keys from breakers, and changed them with my main part of the keys that I have (blade, PCB & Case) basically swapping the immobilizer chip , would I then have two working keys?. Or is it a bit more involved than that?

Your right Jon, the dealership said they had never heard of this happening before just through the battery going flat on the car, and that is why I find it so strange just the chip is no longer reorganized by the ECU.

It wouldn't work, the coil round the lock only 'reads' the details which are checked by the immobiliser ECU which, if the details are recognised, allows the engine to start.

Dead right, the transponder chip is the immobiliser bit. The fob battery is irrelevant to this.

The transponder chip is matched to the EWS (immobiliser) ECU under the dash. The EWS is matched to the engine ECU. So you'd need to change all three to keep the immobiliser happy.

I think, but I'm not sure, that the transponder and EWS use a rolling code that they synchronise when you start up. So the EWS actually writes to the transponder chip. If this was corrupted because of the low battery, it might cause the problem you mention. I thought there was an option on T1 testbook to resync the immobiliser, but I may be wrong. If this is the case, then it won't be needed on new keys as they'll be made to be in sync as delivered.

The barcode is for the remot control, and is for aligning that with the BCM which looks after locking and alarm functions.

Sometimes keys just stop working.

I tried to use my spare unit that was kept on a hook the other day and it would not work. I replaced the battery and nothing. Dead as anything.

MMM, now who has a T1 that could give it a try?

I suspect Mr Lates may have T1 discs.......

Thanks David, its a long way to go, on a whim, T1 might not even work, I will PM Lates and see what he says, if he gets time to replay what with working on Les's tourer :lol:

Shame we can not get access to T1 or T4 at the meeting at Cosford

If it is the buttons that are not working, it may need re synchronising, have a look at the first paragraph in post 7.

Tony just a stab in the dark here !!:shrug:

Are you sure the Tiny chip didn't fall out perhaps when you had a look inside Keyfob?

If not perhaps swap the Transponder chips around between the 2 keys you have, and the "fault" should swap over to the new key.

Have you tried disconnecting Vehicle battery for 15 mins or so as the decaying charge on an old battery can make ECU's & BCU's behave in strange ways until a Power reset is implemented.

Hi Jules, I must admit I have not tried to changing over the chips yet I will give that a try.

As for the battery, I have had it off several times, so I should think it will rule out ECU's ECT, but I will give the chip swap.


Thanks
Tony

just dismantle the case and swap covers....don't try and take the transponder out.....I would suggest a blob of tippex to mark one so you know which one is which...

No luck with swapping chip over, the original key now works, but the replacement key is no longer working, so it must be the immoblizer chip that needs re-coding, now all I have to do is find some way to get clip coded?? anyone apart from Lates have a T1?

The immobiliser ECU is manufactured with the code of ten possible chips, the details of those codes are kept by BMW in Germany, any new key is supplied with the next available code (which is why the keys take so long to come from Germany)

There is nothing in the immobiliser ECU or the chip that can be programmed by T4. I wonder if it is the immobiliser ECU that has 'lost' the details of the chip, have you tried disconnecting the battery for a while as suggested by Jules?

I think we are a bit muddled forget T1 or T4 both do the same thing for keys

You did not say if the remote plip still works as that is the bit that is coded to the car using the barcode and yes using T4 you can read existing bar codes already coded to the car and in that way match them to an existing key if necessary

However you say the car is imobilsed that is nothing to do with the barcodes or T4 it is purely down to the chip as said earlier this is not coded to the car by T4 and I supsect your chip is simply faulty.

Hi Keith
Tony does say in post #1 that the remote blip part works, so it is looking like transponder IC is up the duff.

Am I right in saying the codes don't constantly change in 75 ZT blips like they did with the 600 & 800 range blips? As they could sometimes get "out of step"

Funnily enough my sisters R600 was immobilized only last month!
She called me as she luckily had only stopped at the Petrol station 1 mile away from here. Reported the green key just flashing on the dash, and the starter inhibited.

Mystery is, when I got down there with my whole tool kit, all I did was remove the key, locked the doors manually with the key then put it back in the ignition & Hey Presto it started OK. (her remote blip part has been duff for over a year but the system carries on working just with the transponder key)