Key help

[bigwinn]

Morning all

A quick post for a view please:

I have one key for my 2004 E85, only works manually on the locks- pressing buttons does nothing on central locking.

I have boosted the key using the toothbrush charger, I've tried the key press reset routine several times- nothing the key is still dead.

Before I go to the stealers and source another key OR via another route, what checks should I make to ensure it is the key at fault opposed to the receiver in the car

Had my codes read at the weekend and nothing showed up as a fault in that area?

Thoughts?

Stuart

 

[buzyg]

Almost certainly the key has a dead battery. There are three elements.

The physical key. That works.

The transponder chip that the ECU interrogates at start up. That works.

The remote module that operates the doors roof and windows remotely. That is the bit that needs a battery and it ain't working, so almost certainly the battery is your only problem.

Trouble is the key is not designed to be split. But you can do it apparently. You tube is your friend.

 

[colb]

There are two distinct functions within the key, first one is the little transponder inside the key that is read by the ring around the ignition lock. The ring also provides the charge for the keys internal battery when it is in the lock. The second function is the printed circuit board inside the key that communicates with the EWS locking system when the buttons on the key are pressed. For the central locking function to work on the key buttons the key needs to be synced with the car. There are a few methods of doing this, if one fails to sync the car try the other option. Details on how to are
BMW Z4 - Key Remote Programming

Three methods to try:

Method 1:

1. Working from within the vehicle and with the doors shut

2. Turn ignition to position 1 and back to off within 5 seconds.

3. Remove the key from ignition and press and hold the unlock button for 15 seconds during this time press the key lock button 3 times within 5 seconds.

4. Release both buttons.

5. Doors will lock and unlock to show correct programming has occurred.



Method 2:

To do this procedure you need to have one working key and one key that needs to be programmed.

1) Get in and close all doors.

2) Turn on the ignition and turn off quickly. (No more than 5 seconds) to start the process. Next action must take place within 30 seconds.

3) Remove the 1st key.

4) Hold the key up near your left shoulder (this is so it is closer to the remote receiver antenna.

5) Hold down the unlock button and press the lock button 3 times. Release the unlock button and the doors lock which confirms the operation.

6) Quickly repeat steps 4 & 5 for key #2 etc.

If it does not work, try doing the keys in opposite order. Key 2 then key 1, vs 1 then 2.



Method 3:

Alternate if you do not have a working remote

1. Turn key to position 1 five times very quickly 2. Remove key 3. Hold unlock button then press lock button 3 times, release unlock button.

4. If you have another key do the same button pressing within 30 seconds 5. Turn on ignition to finalise.

PLEASE NOTE: This programming procedure programs the remote control part of the key. Any transponder chip for the immobiliser (starting of car) will not be programmed and must be done by a specialist.

 

[colb]

Following on from what I posted previously it may well be as buzyg says the battery in the key has died. There are people out there that will renew the battery but that means sending the key to them with the risk of it getting lost, not a good option if you only have one key. Dealer supplied key is expensive approx £130 last time I looked. BMW supply a cut programmed key to your car from their records. I bought new key blanks from ebay and had the blades cut by a local locksmith, not all will do this especially the likes of Timpsons. Once the blades were cut I bought an AK90 key coding machine again on ebay that reads the transponder in the key and the EWS module to provide the file to write to the new key so that it cranks and starts the car. Syncing the key(s) to operate the central locking has to be done as per the instructions I posted earlier. I failed to get the AK90 machine to code my new key, I couldn't get a key to crank and start the engine. Gave up in the end and paid extra for a mobile locksmith to code the key with his proffessional coding machine, that read the EWS Board using the eeprom chip on the board, not the same as the AK90 machine. Coded the key to a slot that was allocated to a key I did not have and that gave me a fully working key. Synced it to the car and immediately synced my original key as all keys have to be synced straight after each other.
There are guys on here who use the AK90 machine and are successful with it, just don't know why it wouldn't work for me.

 

[bigwinn]

Thanks all- appreciate the input

 

[Jfgoldfish]

Splitting the key and replacing the battery is very easy IF you can solder. Batteries are also very cheap.
The key then needs to be glued back together but a neat job can be done of that.

Where are you based? I have a spare battery here that I could pop in for you.

Does the button in the car still unlock and lock the doors? That is a good sign that the relays in the gm5 module are still alive.

 

[Mr Tidy]

Alternatively OP if you can get a key or 2 cut there is a forum member in the Cambridge area who can code it/them for you:- https://z4-forum.com/forum/viewtopic.php?f=13&t=110150

 

[bigwinn]

Thanks both

Yeah c/l works in the car fine so hoping it’s just the battery

Key looks like it’s been opened before so will have a look tomorrow

Based in Lincoln

 

[buzyg]

Just occurred to me. If you do need to get a new key cut and are happy to open the keys, then you could swap the little transponder chip over from your existing key, as your car already knows it. I've never tried this. But I can't see why it would not work and save you needing to get your car coded to recognise the chip in the new key. You would then need to follow the instruction that colb posed to set up the new remote module.

Interested to hear if any one else has tried this?

 

[colb]

@buzyg, using the transponder from a duff key can be done but defeats the object of getting two working keys unless of course you are prepared to change the transponder from one to the other when you want to use them. Having said that the replacement keys I got were ebay items and access to the internals were just a clipped in cover on the fob, they came with virgin transponders for coding but once the blade was cut a known good transponder could have been placed in the fob and it would have taken on the identity of the old key. I didn't do that with mine as it was an original key and would have had to be cut open. However I also had a flip style key cut and keep that as a spare which I could put the transponder in from the other new key I had coded if the need arises. Bear in mind mine were for a Z4 so the blade part of that key will be different than that on the Z3. Transponder chip may well be different as well. Member Iamorion on here is well up on coding keys, already mentioned by earlier poster, in Peterborough area.

 

[bigwinn]

battery ordered- firing up the soldering iron

what could possibly go wrong....

 

[Jfgoldfish]

what could possibly go wrong....

That's the spirit :wink:
I'm sure it will be fine! Only two nice large through hole pads to solder up.

Check the buttons all work before gluing it back together. They can be replaced if they are temperamental.

 

[bigwinn]

No dice

Battery replaced and glued back together

Did the key reset-
Once to position 1
Five times to position 1
Etc

Nowt

Central locking still works from the button on the car

Next suggestions please?

Stuart

 

[Jfgoldfish]

I would suggest borrowing a compatible key from someone to check if that pairs with the central locking.
If it does, there is something else wrong with the key.
If it doesn't, there is something wrong with the car.

 

[Jfgoldfish]

Could buy one of those cheap replacements from eBay to try it with.
They are only 3 or 4 quid and would the serve as a donor PCB for getting your key working.

 

[Argyll Andy]

No dice

Battery replaced and glued back together

Did the key reset-
Once to position 1
Five times to position 1
Etc

Nowt

Central locking still works from the button on the car

Next suggestions please?

Stuart

Complete stab in the dark as to if it’s the same problem but when I replaced my battery it opened the doors but not anything else.

I stuck it on a toothbrush charger for about 6 hrs and worked straight away and has done since - 2 yrs ago

 

[Jfgoldfish]

when I replaced my battery it opened the doors but not anything else.

Am I missing something, isn't that its only job?
Or did it not do the boot and roof?

 

[Argyll Andy]

when I replaced my battery it opened the doors but not anything else.

Am I missing something, isn't that its only job?
Or did it not do the boot and roof?

Aye ok smart arse

What I meant was it only worked the central locking and wouldn’t start the car. Did the re-syncing etc. Then charged the key with new battery fitted on the toothbrush charged then everything worked as normal

As I said a stab in the dark

 

[Jfgoldfish]

Aye ok smart arse

Ah, ok. Im with you
As far as my understanding goes, the function of starting the car is separate and unrelated to the battery charge level or even presence.
Giving it a charge is definitely worth a go though; in the case of the OP a flat battery would stop the key from unlocking and locking the doors.

 

[bigwinn]