help immobiliser issues

d8mbn wrote: does anyone know if the immobiliser is part of the ecu or totally seperate as mechanic seems to think it is a seperate item and can it be bypassed cheers

The answer to that is both. It is a seperate system with its own control unit but the engine ecu will not work unless the immo system is working too.

As far as I am aware there is no working bypass.

What you really need to do is to diagnose the actual cause of the issue and repair it. This is normally best done with live data analysis. A specialist dealer level tool is really the only option for this.

HTH

As Autofix said, immobiliser needs to be working in order for ecu to work. In laymans term, the immobiliser 'talks' to the ecu and basically tells it that the correct code has been identified and that the ecu is 'allowed' to start the car. My advice would be to get the immobiliser tested and quite possibly replaced. I have a '94 e34 and my immobilser plays up at times so if they are similar, it wouldn't surprise me if this was your problem.

Don't spend money guessing what could be wrong, sometimes it is best to spend good money on good service.

Hope you get it sorted

Mike

Hi

the imobiliser is behind the glove compartment (ZKU) or under the passenger front floor somewhere.

The key reset above should also allow the immobiliser to work.

Also either disconnecting the battery or pullig the fuses, the ones in the rear by the battery should also re-set the immobiliser.

I heard somewhare that the key has a chip that interacts with a sensor behind / in the speedo, if this interaction doesn't succeed then the immobiliser doesn't switch off. This stops kids hammering a tbar screwdriver in the ignition key to steal the car. This interaction is seperate to the programming of the key entry.

My motor is playing up the remote key entry doesn't always work, sometimes it locks the car, but won't unlock it so I have to resort to key in the lock and turn which sets off the alarm which doesn't seem to switch off this way! I have to quickly disconnect the battery to silence the alarm, the car still starts afterwards. So the immobiliser is seperate to alarm, but related!

I am about to check all the wiring to see why the failure occurs, if I find any immobiliser info I'll post here.

Found a good site immobiliser system is here on the e38 forum. The same principles must work for yours...

http://www.e38.org/EWS.pdf

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Jerry 523i wrote: Reading through the info it looks like even if you get a new one from FAB you will need the corresonding key or need to code the system to accept your own key. I have software from E-bay for reading codes etc, but I don't think it codes keys to ZKE & DME. If I were you I would enquire around  the BMW places and workshops that are BMW specialist and find one willing to check your ZKE and code your key to it. From experience, not all BMW places charge the same, some do a 5+ speclalism, some are just BMW enthusiasts recently BMW main agent quoted me just over £500 for two subframe bushes, a 5+ BMW agent quoted me £375, and a BMW specialist quoted and did 4 bushes work at a little over £350. < =text/>

Hi Jerry,

There is no serial coding possible to add either a new or used key to the BMW immo system. By this I mean that it is not possible for anyone to plug in and code. Neither the dealer nor any specialist I know can do it.

It is possible to code a new key by directly writing the key data into the EWS module eeprom but this entails the fitting of a new eeprom, along with a certain amount of knowledge and equipment. It is common place in eastern european countries with stolen BMW's so for obvious reasons i will not give too much info on this here. Practically, I think you would be a long time looking for someone to do this for you (well you could ring me but I dont do it for anyone).

The coding for the keys, as regards the immo system, has nothing to do with the ZKE. The interface for the immo codes contained in the transponder chip is the EWS module. In fact, if you unplug the ZKE the car will still run.

As I said above, the best solution to a problem like this is to find a specialist who can diagnose the problem through live data. If the immo (EWS) module is at fault its the cheapest module in the car.

It is possible to fit a matched set of immo module, engine module and key but this can cause other problems.

HTH