key code

oskiee6 sent me his receiver, which was identical to a Coupe. I reset it and it operated fine with a Coupe remote I have.
I also have an Alfa remote key which does not work with receiver, and I am wondering what alfa its from.
Its a CODE2 normal shape 1 rubber button, and its been marked P33.
Its obviously got a differnt remote system to the 145.
T.

Originally Posted by Barry

oskiee6 sent me his receiver, which was identical to a Coupe. I reset it and it operated fine with a Coupe remote I have.
I also have an Alfa remote key which does not work with receiver, and I am wondering what alfa its from.
Its a CODE2 normal shape 1 rubber button, and its been marked P33.
Its obviously got a differnt remote system to the 145.
T.

Good work So the conclusion is that you can definately do something to reset the receiver units from the 145/146 which is great news

Just to clarify so it's completely clear, which of the following three is it that you're actually able to do:-

1. Retrieve the original existing 4-digit code stored in the receiver which can then be used to unlock the units for protected programming any time in the future.
2. Reset the receiver unit to virgin status and supply a new code to allow it to be unlocked for protected programming any time in the future using that new code.
3. Just temporarily unlock up the receiver to allow simplified programming of new/existing keys within the next 256 activations/deactivations after which it will then be permanently locked again (i.e. no unlocking code is actually retrieved or supplied).

Yes all of that, plus find the codes from an existing remote which has got out of sync with receiver. That way I dont even need the receiver to load the remote back in again, just the remote key.

Originally Posted by Barry

Yes all of that, plus find the codes from an existing remote which has got out of sync with receiver. That way I dont even need the receiver to load the remote back in again, just the remote key.

Barry, In that case I would quite like to find out the code to unlock my own receiver as I didn't get any of the codes with the keys for my 145 and the code would be useful to have for peace of mind in case anything ever goes wrong.

How much do you charge for the service of retrieving the existing code in a receiver? If you don't want to publicise prices on here then please send me a private message.

help help i am confused to hell with this code stuff.i bought a 146ti 7 weeks ago totaly mint,2 weeks ago i couldnt set the alarm immobiliser and central door lock,so i changed batts in key no luck,went to alfa, they said key no good need a new 1,89£ later, they tryed to code it wouldnt work,booked in for day,told me key module wos faulty 198£ later still no good,told me master key might be faulty or it might not be the master key for that car,i have no codes for the car,but the master key i have will start car no problem,what is going on,i have no idea can any 1 give us a clue

Originally Posted by rusty 146ti

help help i am confused to hell with this code stuff.i bought a 146ti 7 weeks ago totaly mint,2 weeks ago i couldnt set the alarm immobiliser and central door lock,so i changed batts in key no luck,went to alfa, they said key no good need a new 1,89£ later, they tryed to code it wouldnt work,booked in for day,told me key module wos faulty 198£ later still no good,told me master key might be faulty or it might not be the master key for that car,i have no codes for the car,but the master key i have will start car no problem,what is going on,i have no idea can any 1 give us a clue

First things first...the immobiliser (known as the CODE immobiliser) and the alarm system (including the remote central locking) are two completely separate systems and both work completely independantly of each other. The only common thing between them is the key...it has a transponder chip in to deactivate the immobiliser when the key is in the ignition, and it also has an independant remote control circuit in it to activate/deactivate the alarm (and also control the central locking).

If the burgundy master key you have starts your car with no problems then it's the correct master key for your car. I'll ask one question at a time, so forgetting the alarm and central locking for the moment, do either of your two red keys actually deactivate the immobiliser when you put them in the ignition and allow you to successfully start the car?

i know many of you are waiting to here from me regards programming a new pcb (green circuit in the key) to my reciever. barry has both and will try to get them communicating. once i have them back i will keep you all posted. the fact that barry has managed to read the key codes from the reciever makes him a HERO

well got reciever back from barry. the key is coded and works fine operating the central locking. however the alarm does not turn on/off. i have never switched it off on the box in the boot so bit confused. any suggestions would be welcome.

Originally Posted by oskiee6

well got reciever back from barry. the key is coded and works fine operating the central locking. however the alarm does not turn on/off. i have never switched it off on the box in the boot so bit confused. any suggestions would be welcome.

Do you know what it is that Tony actually did to you receiver? Did he 'virginise' it and program it with a new code or just retrieve the original code already stored inside it?

First of all, the alarm doesn't lock or unlock the doors...it's done directly from that receiver in the roof. When the receiver receives a recognised signal from a known key it will send one control signal to the central locking and another (separate) control signal to the alarm box in the boot.

The signal sent from the receiver to the alarm box is a serial data communication (i.e. it is not just a simple on/off signal). In the data is a code that the alarm box is expecting. This expected code is actually the code of the original key that was first used to activate the alarm before the car left the factory. The first time a key is used to arm the system (and lock the doors), the code of that key is stored in the receiver and also sent to the (virgin) alarm box where it is also stored. This then means the receiver and alarm box are "paired" by way of that code and the alarm box will only arm/disarm if it receives that known code. Regardless of which key is used to arm/disarm the alarm in the future, it is always the code of the first key ever used that is sent from the receiver to the alarm box.

If Tony has wiped the existing code in your receiver and replaced it with a new one, the alarm box isn't expecting that new code so will no longer respond to arm/disarm signals sent from your receiver. The only solution is to either wipe the code stored in the alarm box so it becomes a virgin box again (if that is actually possible), or get a new alarm box. With a virgin alarm box, it will then pair itself again with the receiver on first use.

The whole Alarm / Immobiliser setup on these cars is a complicated beast. I know it's good to know that your alarm / immobiliser system is as secure as possible but sometimes I can't help thinking that Alfa have maybe gone a bit too far and just caused too many unnecessary headaches for the real owners of the cars

It is worth speaking to Tony again because maybe he has the know-how to also virginise the code stored in your alarm box.

i did email tony prior to my last post but he isnt sure. i do know that the alarm works fine. alfas fix one thing and your presented with another!

Originally Posted by oskiee6

i did email tony prior to my last post but he isnt sure. i do know that the alarm works fine. alfas fix one thing and your presented with another!

1. Was your receiver supplied to you in a completely reset ('virginised') state?
   
   
2. If no, then was a NEW code loaded into it or was your existing code just retrieved from it?

Tony will know which of these he did so you need to ask him. The answer will determine what caused the new alarm arm/disarm problem and what the possible solutions are.

i think he managed to open reciever after getting origional codes and pointed the new key, pressed the button and it loaded in. im sure he will place a post shortley.

gialloevo4,i found a post on the other site where you say that setting the first key makes a link to the reciever then you need to program a second key that makes a link through the reciever to the alarm. after this you can use any key to operate both alarm and central locking. does this work?

Originally Posted by oskiee6

i found a post on the other site where you say that setting the first key makes a link to the reciever then you need to program a second key that makes a link through the reciever to the alarm. after this you can use any key to operate both alarm and central locking. does this work?

I'm not quite sure which post you're referring to but there was previously a lot of confusion about how the system actually worked so I would take some of the old posts with a pinch of salt as there was a lot of theories being thrown around about which units were paired to which and how various codes were passed about between the different units.

All the information is actually in the technical manuals but it unfortunately it isn't worded in a particularly easy way to understand just by reading it (probably partly lost in translation slightly from the original Italian documents). It was only after past problems and resolutions of various peoples alarm system problems that the puzzle finally all slotted together. The way it actually works in a more understandable description is as specified in the last long post I made on this thread.

If your central locking is working remotely but the alarm isn't arming/disarming and you know the alarm box is definately a working unit then it's almost certain that the problem is to do with your receiver sending the wrong code to the alarm. Unless you have a bad connection between the receiver and alarm box then the only other way this can happen is if the code in the receiver has been changed so that the "pairing" code in the receiver unit and the alarm box no longer match each other. The solution is to get those two codes matching but it's not something you are going to be able to do yourself.

Certainly do a sanity check and re-seat all the connectors in the receiver and also at the alarm box but I still believe your problem is most likely to be a code mismatch issue between the two units.

Originally Posted by GialloEvo94

I'm not quite sure which post you're referring to but there was previously a lot of confusion about how the system actually

i did change the lock on the driver door recently with a new one. would this have some how shorted the electrical circuit?

Originally Posted by oskiee6

i did change the lock on the driver door recently with a new one. would this have some how shorted the electrical circuit?

Very unlikely. The connection between the receiver and alarm box (the orange wire) is simply just a serial line connection for sending data up and down (the same wire is also used to contol the two volumetric sensors in the receiver). The alarm is not connected to the locking in any way so if you'd blown anything it would have been a fuse in the locking circuit but the actual central and remote locking circuits are working fine.

Been busy on different project, so not done much on this. Here's most of the info i have got so far, (see attachment of locked a file).
address 70+ = 08 7f aa aa 00
08 - is the next key loading address ( increments 2 and location increments 4 bytes.
7f - number of counts from ff of door opening (usually 00 in here)
AA AA - occurs when count = 00
00 - occurs when unit is locked

address 00 - 03 not sure but could be codes for alarm

key code block constructed every 4 bytes starting at 04 :-
04 = A7 37 D0 AE (REM CODE)
24 = FC 66 81 E3 (ROLLING CODE ORIGINAL)
44 = 07 67 81 EF (ROLLING CODE PRESENT)

What I do to open rxvr is to re-write 71+ to FF FF FF

When a recvr is opened successfully by remote code (p/b) aqddress 72+ changes to code used to unlock it.

the rest of the bottom r/h corner of the data seems identival on all remotes.
Hope someone can make use of that.

Very useful information and some impressive decoding analysis that you've done. Thanks for sharing it.

However, as always I have a couple of questions:-

1. The receiver can remember a maximum of five remote control codes. If the remembered codes start at block 04 and take up 4-bytes each then this will take up blocks 04 to 17 inclusive for five complete codes. If the "ROLLING CODE ORIGINAL" data starts at block 24 then do you know what bytes 18 to 23 are used for, or are they just unused bytes? (those bytes are all set to "FF" in your example)
   
   
2. What do you mean by the terminology "ROLLING CODE ORIGINAL" and "ROLLING CODE PRESENT"?
   
   
3. Given the stored hex code of a remembered key (i.e. "A7 37 D0 AE" starting at block 04), is it possible to determine the actual 4-digit password code for that key (i.e. the code needed to unlock the receiver using the button on the bottom of it)?

Answers

1. The example actual code has 4 keys installed and can take another
3, I believe taking total to 7 keys. after that the first one is written over and thus rolled out of the system

2. when you load in a key it puts 4 bytes in rolling code original, and the same 4 bytes in rolling code present. each time you press the button the rolling code present advances by a preset amount (not calculated). I suspect that there is a calculation done to ensure that any new rolling code entered must be within some limits of the present code, but not less than. This is why removing batteries can cause the key to get out of sync.

3. Yes I have made up an algorithm to calculate the unlock code, but not prepared to divulge it yet, but here's the unlock code for the bytes you offered:-
0757
If you can work it out from that you deserve to know.

Hi,
Ive read your posts with interest, looks like you guys understand the alarm better than most. My trouble started yesterday when the car (99 GTV) wouldnt unlock and so i changed the batts, nothing. Car started but the alarm was going off, then the alarm stopped and I drove home with the red led flashing. I tried the other fob, nothing, and the other fob with new batts, still nothing.

So I disconnected the battery and went digging to find the alarm, I cleaned all the relays and turned it off/on with the little key and then reconnected it all. Now not only do the fobs not work but it wont start and the code light is on. I thought I was safe here as it had a separate TX chip but maybe I screwed the immob by playing with the relays

Originally Posted by david adlington

My trouble started yesterday when the car (99 GTV) wouldnt unlock and so i changed the batts, nothing. Car started but the alarm