Intermittent failure of immobiliser

[Diamond Ric T]

Thank you bazzbazz.
One day - a few weeks ago - I saw the IMMOBILIZ FAILURE dash warning. Upon trying a second time, everything worked so I disregarded the warning. slowly but surely, the problem came back. So goping from 1 fail to every 20 attempts, I went up to 50/50 and then, finally, 100%fail. My ALFADIAG program has reported an error in the transponder. Mr Minit keyman reckons almost surely that the key itself is losing power. I am going to take it (the key) over tomorrow to see if he can read a code from it. If he can, he can sell me a substitute key that hopefully will work. Fingers crossed.

[bazzbazz]

In this case the Mister minute man does not know what he is talking about. The immobilizer chip in the key is PASSIVE!! The car interrogates the chip in the key, the chip is not powered in any way.

The battery normally contained in the 147/156 key FOB is for the remote central locking, not the immobilizer system. The problem in with the car, not the key.

ALFADIAG is simply saying it cant see the chip, usually due to

A/ The Aerial Ring failing. (They do on a regular basis)
B/ The connecting cable to the Body computer having a bad connection
C/ Faulty connection/Fault in the body computer itself.

[Diamond Ric T]

Today I may (or may not have) lurched forward in this very frustrating immobiliser problem. The smart money was on the aerial ring that surrounds the key barrel. Today I took the one from my other 147 (which I know works) and put it on the non worker. I took the one from the non worker and put it on the worker. The worker still worked and the non worker still failed. Double blind test. Proves that it had nothing to do with the transponder aerial ring. I took the key to a locksmith and explained to him that it was a passive key. He tested it and said that it could not be read.  Dead as a dodo. I called an Alfa service centre here in Sydney and he said that the type of key that I had was notorious for "dying". (It is a blue key - made in Spain). He gave me an option. They can use the VIN of the car to identify the code and have a genuine replacement created. Not sure how much yet but he said maximum $500. Seems like it's pay the spondooly or the car goes to the boneyard.

[Citroënbender]

If Vlad from Arese can't help, give Mick at Shop4Parts a call tonight. You should be able to get new genuine keys for a bit less overseas. 

Option B is an "immo off" procedure to the system, I'd think this is about £100-120 plus return post to the UK - not sure if I'd want it done locally, for a number of reasons.

[bazzbazz]

You got a photo of this "Blue Key" ?

The only way you can kill the immob chip for the 147 is to somehow smash the glass chip inside the key. Stood on the key lately?

[Diamond Ric T]

Hi Bazzbazz
Here is a photo of the key. My great fear is that if I pay all the loot for a new key and it doesn't work.

[Citroënbender]

Ric, I suggest you crop the photo to obscure the blade. 

[bazzbazz]

Gotta be honest, never seen a key like that, but find it hard to see how the chip in the key could "Die Slowly". You have to understand, the passive chip in the key either works or it doesn't, it's either broken or its not. The fact that yours had somewhat of a progressive failure, suggests logically that it must have something to do with a failure/faulty connection within the Body Computer.

Also you need a rather advanced reader to read the 147 chip, a standard reader won't read the chip. (Alfa Romeo being too bloody cleaver once AGAIN!)

Did you unplug/plug/clean the connecting lead from the aerial ring to the body computer where it connects to the body computer?
Did you check that lead for continuity?

Any Alfa wreckers in your area?

[Citroënbender]

I see we are here again. 

Bazz: What actually happens if one puts a three door body computer in a five door? They appear to have the same part number. Can't you edit the body configuration in the module?

Ric: I have some stuff: a three door facelift body computer and manual 2.0 ECU, one only original key chip, VIN "tag" and cluster with 128K, you could have it in your hands within the calendar week.  Also, available soon, a 2.0 manual pre-facelift kit with two original key chips and 165K.

[bazzbazz]

I've done it myself a long time ago, tried to put a 2 door body computer into a 4 door car, the unit wouldn't recognize there were any rear doors.

[Deet]

My Daughters 147 has now got the intermittent immobiliser issue
Local Auto Electrician replaced the reader, and says there are no error codes, but every week or so she gets stuck for up to 20 minutes with a car that just wont start.

The Auto Electrician is now refusing to look at her car again.

I was thinking of seeing if a connection clean of the body computer might help.

Can someone tell me where its located?

Or maybe I may need to get a used set of bits and just replace the lot.

its a 2002 147 manual 5 door BTW (pre face lift)

As a side note the odometer was blinking when I was last in the car. Related?

[bazzbazz]

Ok, Blinking Odometer means that the Body Computer has at some time lost connection with one of the other ECU modules within the car and a Proxi-Alignment needs to be carried out, to re introduce the body computer with all the modules again.

Now, with your daughter car refusing to start, does it come up with an immobilizer warning on the dash, or it just turns over and refuses to start?

Need to know that before we go any further.

[Deet]

It has the immobiliser warning on the dash

the Sensor ring was replaced, and the keys re-programmed in

[Deet]

Sold the car, so dont worry