Anti-theft alarm

V

Vic

Member
Hello,

first of all want would like to introduce myself. I am 2001 1.4TDI Audi a2 owner from Lithuania.

So few weeks ago wanted to find out why my alarm system is not working since I bought a car (tested with locked car and open window). Checked the fuse, alarm off button is not activated, sensor is connected.

After reading post about Siren backup battery replacement decided to check mine alarm but i found only alarm horn (tested it directly on 12v).

So maybe somebody have any thoughts why anti-theft alarm system is not working? Or where the module of alarm system is?
 

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Vic said:
Hello,

first of all want would like to introduce myself. I am 2001 1.4TDI Audi a2 owner from Lithuania.

So few weeks ago wanted to find out why my alarm system is not working since I bought a car (tested with locked car and open window). Checked the fuse, alarm off button is not activated, sensor is connected.

After reading post about Siren backup battery replacement decided to check mine alarm but i found only alarm horn (tested it directly on 12v).

So maybe somebody have any thoughts why anti-theft alarm system is not working? Or where the module of alarm system is?
Click to expand...

Are you 100% sure that it is being set? If the car thinks a door, the tailgate or the service flap on the bonnet are open then it will not set.

Do the indicators flash briefly when you lock the car? If not you need to check all doors are shut, but it is often the service flap that is not fully closed. Sometimes you have to stick on a small object to the flap where it contacts the rubber alarm button, or it does not compress it enough to close the switch properly?

It might even be a broken microswitch or solder to it. This "tells" the car that the door is closed.

Steve B
 
Yes the indicators flash briefly when car is locked and all doors and trunk is locked.
The service flap is closed and i checked rubber alarm button with multimeter - it is all working fine.
 
So when you try to trigger the alarm deliberately do the hazard lights flash or are you getting nothing at all?

I haven't really come across an alarm that will not set, so it could be a tricky one to diagnose.

I MIGHT be that the alarm has been disabled via VCDS or similar, perhaps there were some false alarms and so a previous owner has disabled it?

A VCDS scan would be the next step to check the settings and also to check the CCCU and see if there are any error codes.

Do you have access to VCDS at all?

Steve B
 
As you indicated, from your first photograph it looks like the previous owner replaced the siren module with a basic horn - possibly due to back up battery failure and the expense of fitting the proper replacement part.
I suspect the Audi siren module acts as the main control unit for the alarm system so its unlikely it will work until you fit the correct part. Hopefully nothing else in the system has been messed around.

If you buy one from ebay, get the later version as shown in the battery replacement guide. I had the earlier version on my 2001 tdi and tried to cut it open but it was almost impossible due to the much tougher plastic used on the casing (This was long before the new guide was published)

Cheers Spike
 
Unfortunately i don't have access to VCDS but thinking to order vag cable.

I can order siren module from Ebay but i see there is 3 pin connector in it. My siren is connected with 2 pin connector and there is only 2 wires (+-). I did not see any aditional wires.
 
It may be a 3 pin connector but the wiring diagm shows only 2 wires to the alarm unit.
H8 is the alarm module and J393, the central convenience unit

Cheers Spike


A2alarm.JPG
 
Ineteresting. So why there are 3 wires..

dsc00142.jpg



And maybe you know which wires from alarm module goes in CCU?

IMG_0634.JPGIMG_0636.JPG
 
The alarm in the last picture is probably from a later model Audi (possibly TT) which has an additional live feed from the fuse box.

As far as I know the A2 wiring harness was never updated even though the original alarm module was obsoleted and replaced with a later version used on other Audi models which use the 3 wires

The wiring diagm I already posted shows the connection to the J393 CCU on the A2

Cheers Spike
 
Vic said:
Ineteresting. So why there are 3 wires..

View attachment 40341


And maybe you know which wires from alarm module goes in CCU?

View attachment 40342View attachment 40343
Click to expand...

Hi,

the 3 wires are ground, permanent +12 power supply and trigger. The alarm siren is provided with power all the time to keep the internal batteries recharged. The trigger wire makes the noise.

Brown = ground
Red with blue stripe = +12v power.
Red with black stripe = trigger

The trigger should go to pin 7 of connector "1" according to the diagram.

The option of a horn with battery backup seems to be a later fitment, early cars only having a "dumb" siren.

regards

Andrew
 
I have a May 2001 TDi so had a look at the alarm siren wiring and surprise, surprise as Andrew indicated its a 3 wire system.
I've been back over the wiring diagms which all show the change from 2 to 3 wires happened in 2003 - and nothing to suggest there were differences between UK and European build specs

So Vic, while I had the best of intentions, I've given you duff information.
Your car was almost certainly built with a basic 2 wire horn, so replacing it with a later 3 wire siren unit is unlikely to be the fix.
Difficult to be certain without a diagnostic scan but there's a chance its down to a faulty CCU not providing the trigger voltage to your 2 wire horn.
As others have said, the alarm is set by 'closed' signals from the doors, boot and service flap all being present and correct. Again, a diagnostic scan would confirm this and give more certainty to the CCU being at fault.

Cheers Spike
 
Address 46: Central Conv. Labels: None
Controller: 8Z0 959 433 J
Component: Komfortger·t T05 0615
Coding: 06752
Shop #: WSC 00861
3 Faults Found:
01559 - Drivers Door
61-00 - Won't De-Safe
01560 - Passenger Door
61-00 - Won't De-Safe
01562 - Right Rear Door
61-00 - Won't De-Safe

Can be anti-theft alarm system is not working for this?

There are no more exept this and some climate control faults.
 
Vic said:
Address 46: Central Conv. Labels: None
Controller: 8Z0 959 433 J
Component: Komfortger·t T05 0615
Coding: 06752
Shop #: WSC 00861
3 Faults Found:
01559 - Drivers Door
61-00 - Won't De-Safe
01560 - Passenger Door
61-00 - Won't De-Safe
01562 - Right Rear Door
61-00 - Won't De-Safe

Can be anti-theft alarm system is not working for this?
Click to expand...

Hi,
these items relate to the operation of the micro switches in the door locks that detect the position of the lock/unlock motor. They won't affect the operation of the alarm. This is triggered by the switch that turns on the interior light when the door is opened.

regards

Andrew
 
I think i found where the problem can be. VCDS shows that hood contact switch is not installed.
It can be wiring problem because switch in fact is installed.

Screen Shot 2018-07-12 at 10.00.02.png
 
It could be that it is simply not making enough contact to depress the button.

I recently had to glue a 20 pence piece onto the flap to make up for the gap?

Have you added the alarm beep to the code on the CCCU coding (adding 1024) because at least then you will hear a beep if everything is closed properly when you lock the car?

Steve B
 
I think it should be Active or Not oper. when switch is on or of (like fuel tank switch) but not "Not installed".

No added code. How i can know the code is not already added? And if already added so what will be when i will add 1024 again? I am using VCDS Lite.
 
Make a note of your existing code, add 1024 to it and try it (making sure that all doors, the tailgate and service flap are fully closed and see if it beeps on locking). If it does not work then revert to your old code.

I will check my code tonight and so you can use that code in yours and you will know that it is switched on.

Steve B
 
Are you saving it after adding it ? (perhaps VCDS lite doesn't do this kind of change)

Steve B
 
Remember that not all CCCUs have full functionality. All UK CCCUs are of the highest spec, but many CCCUs in Ireland and Central Europe don't have the complete range of features that UK owners are all used to. If the CCCU keeps rejecting its coding, that's possibly because it doesn't have the ability to implement the requested change.

Specifically, not all CCCUs have the an integrated alarm system. 2001 A2s were fitted with extremely unrelaible CCCUs - I've changed more of them than I can possibly remember. It is therefore entirely plausible that the CCCU has been changed in the past, but that the person who changed it fitted a CCCU that doesn't have all the required features. This would explain why the alarm doesn't set, why the sounder doesn't beep, why it won't accept the +1024 coding change, etc, etc.

Alternatively, a replacement CCCU with the required functionality has been fitted, but this functionality isn't coded. For instance, the coding to activate the alarm system is a prerequisite of any further alarm-related coding being accepted.
An example: The alarm system is activated using the 4th coding bit (you add or subtract 8 from the code). The beep-on-lock function is activated using the 11th coding bit (you add or subtract 1024 from the code). But you cannot activate bit 11 unless bit 4 is active.

Cheers,

Tom
 
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