Faulty Key chip

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Tilly
Joined: Wed 26 May, 2004 19:45
Posts: 439

  M roadster S50
Location: Sussex

Faulty Key chip

Post by Tilly »

On Saturday after a day's great driving I had problem starting the car. Luckily it was on the drive and I just wanted to put it in the garage. Ignition on, no problem, but on turning it to position 3 nothing.

The central key is the three button remote control version which not only contains the battery controlled alarm function and interior light control but also a chip for the electronic immobiliser. The alarm and light functions worked but the car would not start suggesting the battery in the key was fine which was confirmed by the illumination of the key LED.
When new the car came with five keys. Two for the optional boot rack case, one door and ignition key, which does not operate the luggage compartment and storage bin, and two central keys with remote control transmitters.

When I tried the other central key and the door and ignition key they both started the car. Also with the dud key in the ignition, if either of the other keys were in the car it would now start. This suggested a problem with the key immobiliser chip. I tried to re-initialise the remote keys using the following procedure. Sitting in the car with the doors closed I put the functioning central key in the ignition, unlocked the steering (position1) then quickly turned it back to zero. I removed the key from the lock, held down unlocking button and then quickly pressed three times on the locking button. I then released the unlocking button and the LED started flashing. The central locking system then worked, locking and unlocking the car, confirming initialisation had occurred. Then within 30 seconds, not touching the ignition lock, I repeated the process with the faulty key and once again on finishing the sequence the central locking system operated showing initialisation was successful. However the key still did not start the car. A faulty chip.

There seemed to be two options. Firstly get the key repaired by a specialist car locksmith for around £45 or get a new key from BMW for £140. I am fairly sure the first option would be fine but for my piece of mind I have decided to take the second and order directly from the main agent. When the key comes they will phone and on visual proof of identity they will check and initialise the key in the car and then extract the dosh from me.
Apparently this is a rare event for a chip to fail like this but at least the car was at home when it happened rather than miles away or just after I had bought some ice cream at the local supermarket!
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BladeRunner919
Joined: Fri 17 Feb, 2012 20:18
Posts: 2225

  Z3 roadster 1.9

Re: Faulty Key chip

Post by BladeRunner919 »

It sounds like you still have more than one working key, so I'd have gone for option 3 - don't worry about it!
Tilly
Joined: Wed 26 May, 2004 19:45
Posts: 439

  M roadster S50
Location: Sussex

Re: Faulty Key chip

Post by Tilly »

BladeRunner919 wrote:It sounds like you still have more than one working key, so I'd have gone for option 3 - don't worry about it!
Good point. Didn't think about that. Just wanted to keep the car as I got it.
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Robert T
Site Admin
Joined: Mon 12 Jun, 2006 10:35
Posts: 10170

  Z3 roadster 1.9
Location: Cheshire

Re: Faulty Key chip

Post by Robert T »

You could do with getting the car plugged into INPA. This will tell you what the key is actually doing, including showing you the code that the car has read.

As I understand it, the code is cyclic, so I am wondering if it has just got out of sync and will come back round into sync eventually. This happened with the remote on mine (which is again a cyclic code) and it took quite a few presses of the remote to get it back into sync. It might be a more complicated cycle, so this might be a non-starter, as it could take several years to come back around! It might also be that the key is able to transmit the current code, but not generate a new one, which would explain why you can initialise it, but still not start the car.

I am slightly puzzled at the key working when the other keys are in the car. The chip in the key is read by a loop of wire in the ignition barrel and this has to be in very close proximity in order of it to work. It doesn't sound plausible that a key in your pocket could disable the immobiliser. I think it is more likely that the immobiliser has remained deactivated AFTER you removed a working key - I know it does do this for a set period of time - I'm not just sure how long - maybe as long as 30 seconds. This confused someone who bought a replacement key blade (without the chip) and it appeared to start the car. It only did so because he had used a working chipped key first, turned the car off, then restarted it with the blade-only key!

Assuming the worst and that you are going to need a replacement key, then the cheapest option might be a "grey service key" from BMW. The last time someone asked for one, it was about £60. It is basically just a key blade with a chip. You could then (in theory) take the chip from the replacement key and put it in your non-working remote key. There are a few threads on here on the subject of the grey service key and I am desperately trying to recall if someone actually did a successful transplant or whether it was only talked about. Definitely a cheaper option, particularly as your remote electronics are fine.

Cheers R.
Arctic Silver '99 Z3 1.9 & Black '59 Frogeye 1275cc
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Tilly
Joined: Wed 26 May, 2004 19:45
Posts: 439

  M roadster S50
Location: Sussex

Re: Faulty Key chip

Post by Tilly »

Thanks R for the info.

I have tried recyling many times and still no success.
As to the key working with others in the car I've tested different options of time and distance. Time doesn't appear to be the factor. Distance is. If the other key is about four feet away from the ignition then it doesn't work irrespective of the delay. With respect to the grey option then I do not feel competent to remove the chip and insert it correctly into the old housing.

Just one final note. I have a garage remote close to the key and wondered if interference between the units could have cause the problems. I have odered a new unit but I will keep experimenting with the old one to see if I can shine some more light on ther problme.

Once again thanks for your help.
mrscalex
Joined: Fri 13 Mar, 2015 09:14
Posts: 910

  Z3 roadster 1.9

Re: Faulty Key chip

Post by mrscalex »

If you think the key is faulty then I have details of a very good key repair specialist. He managed to bring my 2 year old VW key back to life after the missus put it through the washing machine. Price £30. Mind you I did have to get it reprogrammed afterwards at a cost of £60. Cheaper than a whole new key at £175 though.
ImageImage
2001 Z3 2.2 Topaz Blue (Trudy) - Keeper rebuilt from a write-off
2002 Z3 2.2 Titan Silver (Cookies) - Keeper rebuilt having been bought with a seized engine
2002 Z3 3.0 Sapphire Black (Peanut) - Keeper awaiting rebuilding having been bought as an abandoned project
Plus Willy, Kodak & Maycee - All 2.2 Sport projects. Yes, 6 is a lot of Z3s :)
Always happy to try and help with spares :)
Tilly
Joined: Wed 26 May, 2004 19:45
Posts: 439

  M roadster S50
Location: Sussex

Re: Faulty Key chip

Post by Tilly »

mrscalex wrote:If you think the key is faulty then I have details of a very good key repair specialist. He managed to bring my 2 year old VW key back to life after the missus put it through the washing machine. Price £30. Mind you I did have to get it reprogrammed afterwards at a cost of £60. Cheaper than a whole new key at £175 though.
Thanks for the offer. Have ordered a new key from BMW. Although it will be £50 more than taking the route you suggested it comes with minimum hassle.
Once again though much appreciate the offer.
Tilly
Joined: Wed 26 May, 2004 19:45
Posts: 439

  M roadster S50
Location: Sussex

Re: Faulty Key chip

Post by Tilly »

Key arrived, initialised and working within 24 hours. Key came from Northampton but the coding was sent from Germany. I must admit the service was very good. Price £140.63. I am now going to play around with the old key to see what I can find and salvage.
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