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)