# Key + immobiliser



## shurcomb (Jan 6, 2007)

Hi,

tried using my second key today to start and move my car, but when I put the key in the ignition the immobiliser symbol came up on the dash. Although the key started the car it then died, presumably due to the immobiliser kicking in.

Checked the manual and it doesn't really state much. I am also sure when I first got the car I checked all the keys worked etc..

does it mean my second key, which isn't used on a daily basis, has a flat bettery and needs new ones or is it something more awkward/expensive?

any info appreciated,
thanks


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## kite (Sep 3, 2006)

Try re syncing the keys


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## shurcomb (Jan 6, 2007)

OK, read the handbook yesterday and it doesn't really help with key issues.

How do I re-sync my key?

thanks,


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## graham225 (Apr 5, 2004)

Insert key into door lock, turn clockwise and hold for a few seconds, that should do it.


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## John-H (Jul 13, 2005)

Hi Stuart,

Unfortunately the radio transmitter for the remote, which may occasionally need re-synchronising, has nothing to do with the immobiliser chip. The car should still operate without a battery in the remote part of the key.

It's either the the transponder coil on the steering column, the dashpod, or the ECU (unlikely the key if you've tried the spare). Or connections between these items. The dashpod talks to the key via the coil and encrypted key signalls are pased between dashpod and ECU. If there is a problem the ECU cuts out after one second.

The transponder coils are usually very reliable, the dashpods, as we know, have more problems, but the ECU can cause this too - but is less likely. Most likely then is the dashpod - in which case it's a free fix by AUDI but I can't be 100% that's where the problem lies.

You could try disconnecting the battery to reset the system and see if that does anything, but even if it clears, the question would be how did it get in that state and will it happen again? Still if it does clear it would tend to indicate a software lockup type problem rather than a hardware fault, although it's likely the degrading memory in the dashpod or ECU that caused the software to get into a funny state - or as some people are reporting, being parked next to a powerful radio transmitter. Could that be the case or lightning which can also cause strong interference?


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## shurcomb (Jan 6, 2007)

Hi John,

Thanks for the info, but it is only my spare key that is giving me trouble. I have not used the spare key in the car for approx 9 months, so had thought it was due to the battery or lack of sync due to the amount of time it has not been used for. 
Although the key did unlock the car remotely perfectly OK first time :?

If my dashpod was at fault or the ECU's then would it not be affecting my main key which I use on a daily basis?

Thanks,
Stuart


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## John-H (Jul 13, 2005)

shurcomb said:


> Hi John,
> 
> Thanks for the info, but it is only my spare key that is giving me trouble. I have not used the spare key in the car for approx 9 months, so had thought it was due to the battery or lack of sync due to the amount of time it has not been used for.
> Although the key did unlock the car remotely perfectly OK first time :?
> ...


That's a good point Stuart. Sorry, didn't realise it was only the spare key with the problem - must read more carefully  . Two possibilities then:

1/ The spare key's been damaged.
2/ You've had the dashpod changed and the spare key wasn't given to the dealer - it needs to be presented to the car for coding when a new dashpod is fitted. Has the spare key ever worked? - perhaps a previous owner had the dashpod replaced?

John


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## shurcomb (Jan 6, 2007)

Hmm not aware of the dashpod being changed by previous owner.

Plus was fairly certain I had tested both keys when I first got the car to make sure they all worked, kinda the logical thing I would do, then randomly choose a primary key and kept the second as my spare at home.
Maybe it has been damaged, but don't really see how or any signs of abuse to the key :? 
will try it again over the weekend and re-sync to see if that does anything.

I assume if I can't get my spare key to work, then it will be a trip to the stealer to get it re-coded at a cost  no doubt.

Thanx,


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## John-H (Jul 13, 2005)

When you tested the key are you sure you started the engine with it or just that the remote locked and unlocked?

Another thought; one of the dashpod problems is a slowly weakening memory. It tends to show up first at extremes of temperature, but it can manifest itself in a number of ways: dancing needles, flashing display, fuel gauge offset error, immobiliser, to name a few. I even heard and saw a picture of a little cluster of rogue pixels on the DIS that came and went and was growing with time. Basically any part of the programme memory can start to corrupt. Some parts cause the processor to crash some have more subtle effects. There is a possibility the encryped key code area is effected in yours and it's just knocked out the spare key. It could have done it some time ago and you've only just noticed. If this is the case it's a dashpod fault and you shouldn't have to pay for it.

It may be the key of course. You could try heating the key with a hot wet cloth in a plastic bag wrapped around it to see if the fault goes away with heat. Similarly pop it in the freezer for a bit and try again. If this makes a difference at least you know it's the key.


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## lennio (Jun 9, 2008)

Hi

New to the forum, did you manage to sort this problem, i have exact same problem with my spare key thats hardly used?

Paul


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## mk2zetec (Dec 27, 2015)

lennio said:


> Hi
> 
> New to the forum, did you manage to sort this problem, i have exact same problem with my spare key thats hardly used?
> 
> Paul


Me too!
Tried the key matching procedures but neither work. Any ideas?


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## John-H (Jul 13, 2005)

Did it used to work? There have been cases where people have had the dashpod replaced and didn't give the spare key to the dealer so only the key they drove to the dealer with got coded into the new dashpod, so the spare no longer worked.

The re-synching procedure is only for the remote locking. The transponder for the immobiliser needs programming into the dashpod with special software - see the Mk1 Knowledge Base.


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