Last week my keyfob refused to unlock my car. Details explained here in last (#46) post
I searched this forum for an answer and frankly could find no straight forward solution. Lots of folk seemed to post half information like "do X-Y-Z, this gets you into programming mode" then nothing. What use is that??
Any explanation needs to be complete - so any dummy can follow it
So, best advice I found was to send my key off to Chris, buying a repair via his eBay service. I contacted him here, by PM and he said "sounds like a key fault. Send to me. If no problem, I will return it and refund cost less postage". Fair enough. Sent key Saturday. He had it Monday. Emailed me that it worked perfectly and he would return and refund my money. I had it back Tuesday.
In the meantime I decided to bin the alarm as the car will function without, so I disconnected it but left it in position. For anyone doing this, to remove the wiring plugs from the alarm body, it needs the middle of the top of each plug pressing in, to release it.
It is often stated that the key might not activate the alarm if the aerial around the ignition key is broken. You can tell it is not if, when you turn the key in the ignition so the lights come on and the CODE light goes out, this means that the immobiliser IS connecting with the key. I believe the alarm uses the same aerial (correct me if wrong). So if the code light goes out, the aerial is not the problem.
Anyway, good as his word (STAR BLOKE) Chris gave me the routine needed to re-activate or connect my key to the alarm system.
I disconnected my battery -ve terminal again and re-connected the plugs to the alarm. Shut doors, bonnet and boot and reconnected the battery. The alarm will reset itself and both my keys still did nothing. (If you have not disconnected the alarm, no need for this).
Get in the car and wait for the alarm to shut up! Then pull the battery from the key. Replace it. Press the button twice. Keep doing this till the key works the alarm and locks.
It worked first time for my first key. For the second key, I lock the doors using 1st key (I'm still in the car) and repeat this remove/replace/2 pushes of the button. After 8 or 9 attempts, the key reconnects with the alarm and BINGO. I have 2 functioning keys again
Chris advises that this usually works in less than 10 attempts but he has known one person take 35 goes.
If it still will not engage, either dump the alarm of spend ££££s with your dealer.
I hope this helps. This is specifically on my 156 but probably works on 147/GT too.