Alarm diagnostics?

[mk4gti-t]

Ok so the last couple of nights my alarm has gone off at roughly the same time. Is there any way of seeing what it was that triggered it? Is it possible to interrogate the alarm via vcds? Cheers.

[bacillus]

A normal scan should flag up if your siren is faulty.

[mk4gti-t]

There's no errors on a full scan. I just wondered if there's any blocks etc... that can be looked at to see which sensor was triggered to activate the alarm.

[skard]

Measuring blocks in CCM (46) can show you the previous triggers.

I've replaced a couple of sirens over the years as their internal battery has given up, but faulty interior sensors, damaged wires or main battery failing can also be the culprit.

[MateyGuv]

I had unreal problems with my alarm last year and after a scan was indicated problem was rear lock so replaced that, then the vw logo handle and so on. Turned out to be the inner ignition barrel micro sensor switch. Do you hear a clicking every now and then while driving?

[kth286]

Wondered if Skard and others could comment on my alarm problem as follows:

VCDS points to J393 convenience central control unit problem.

The battery has been running down and now having to charge it daily
even though it's a recent new battery.

Address 19 CAN Gateway flags 1 Fault 01330 (J393) 004 No signal/communication
Intermittent.
Freeze Frame shows Fault Frequency 105.

The car is new to me these past 4 weeks. (Mk5 1.9Tdi late 2004)

Other addresses 09 19 42 46 52 56 are showing up faulty J393

IN your experience would this module J393 cause battery drain ?

What is cost of this unit ?

Can I swap over unit and leave with factory settings for time being and recode later ?

Any thoughts would be appreciated.

New to forum and it looks great.

Based in READING area.

[skard]

Hello and welcome.

It appears your CCM is at fault more than the siren. You can use a second hand CCM but it'd need recoded to your car and your key fobs need synced with it - so best install it and put it on VCDS right away. Ideally find you the part number of your current one and replace with the same as some are specific to 3 or 5 door, and in 2005 the communication protocol changed.

There are members near to you with VCDS if you don't have it, the CCM is behind the glovebox and easy to get to.

To test if your alarm is working, lock the car with the fob, wait a few seconds then unlock with the key blade. Get in and wave about to set off the ultrasonics, if your indicators flash but there's no alarm tone then your siren is gubbed.
I have replaced a few of these sirens though on my mk5's, even though they set off when intended, sometimes it'd also go off randomly. You can get a used siren for £20ish or a new one from Aliexpress for about £25. A new one from VW is about £130

[kth286]

Thanks Skard.

Great to get a quick informed response - thanks a lot.

I will continue my investigations bearing your points in mind.

David

[kth286]

Further to my previous post, now found a current drain
which fluctuates between 0.1 to 0.2 amps on fuse F15 (7.5 amp). Dash side
fuse box.

This fuse seems to be for Multifunction Control Module 1 according to a
chart found online. Why nil chart inside cover ?

Would you knowledgeable enthusiasts concur that's a reliable assessment ?

Does this prove my J393 module is therefore faulty ? as indicated by VCDS

If so, next thing I guess is unplug the module and check it stops the main battery
current drain.

Am I on the right track ?  Completely new to Volkswagen so feeling my way.