Alarm Goes Off Randomly

[renold458]

Has anyone had this issue? I was at my sister's house and I could hear my car alarm go on and off. The first time I went to check as I thought someone hit it but there was zero damage and I disabled the alarm by pushing my trunk button (nothing else turns it off as my key fob doesn't work correctly). As I go back in it goes off again and then it was a game of the boy who cried wolf as it went on and off whenever it wanted. I pulled codes and some central convenience module codes came up (faulty). I'll pull em again and post the specific code this afternoon as I'm an idiot and forgot to write it down. Where is this module so I can check it and is it expensive to replace?

[Luxus Panzer]

bad batts in alarm horn. Remove it

[customa4]

It's probably one of the doors not registering as closed that's setting the alarm off. Either that or the hood or trunk is not registering as closed. Unfortunately without the codes there's not much you can do. This was happening to me when my hood latch wasn't registering as closed and the alarm would sporadically go off.

[Luxus Panzer]

It's probably one of the doors not registering as closed that's setting the alarm off. Either that or the hood or trunk is not registering as closed. Unfortunately without the codes there's not much you can do. This was happening to me when my hood latch wasn't registering as closed and the alarm would sporadically go off.

Yes, this as well.

Get the codes

[KHARDa4]

When mine was doing that it eventually got to a point where my alarm stopped working altogether. Stored codes showed a fault for h12 alarm horn. If you have that code then the batteries inside have come apart and the acid is shorting the board out. Very common. In the cluster does it show something open? Door, trunk, hood?

[diagnosticator]

The ECU box in the plenum MUST be checked for water inside the box. If there is water inside the ECU box, symptoms include the alarm sounding randomly and/or the rad fan running with the key OFF, starting up and stopping at various intervals. Either symptom can exist without the other.

[renold458]

Thanks for the input guys, Im almost done with classes so I'll grab those and post the codes. I do recall one of my doors not being able to lock period, I had a code for that. And in the meantime for some more added info the turn signals go off and the sound doesn't always go off. I'll be back with those codes in about 2-3 hours. I appreciate the help.

[renold458]

Okay, so I don't have VCDS so bear with me on the formatting and code numbers and stuff. I use a Vag Scanner to grab the code so I'll be using the categories from that, I have a Macbook so I unfortunately can't use the VCDS software. Anyway, I'll obviously skip the engine and transmission codes as they're irrelevant here and I will post them elsewhere, so anything "electric" related I'll drop down. So here goes:

-----------Air Bag System:

00532 Supply Voltage B+: Sporadic 002 - Lower Limit Exceeded

-----------ABS Brakes System:

01826 Sensor for Steering Angle (G85) Supply Voltage Terminal 30: Static - No define

-----------Auto HVAC System:

01274 Air Flow Flap Positioning Motor (V71): Sporadic - Blocked or without voltage
00604 Potentiometer Positioning Motor for Air Flow Flap (G113): Sporadic - Open/short circuit to positive
01592 Air Quality Sensor (G238): Sporadic - Open/short circuit to positive
00532 Supply Voltage B+: Sporadic - Power supply too small

-----------Cent. Elect. System:

00532 Supply Voltage B+: Sporadic - Power supply too small

-----------Steering Wheel System:

01330 Central Control Module for Central Convenience (J393): Sporadic - No communication
00532 Supply Voltage B+: Sporadic - Power supply too small

-----------Instruments System:

01304 Radio: Static - No communication (I have an aftermarket stereo so that might be why I get this code, it was installed prior to my purchase of the car)

-----------Int. Monitor System:

01463 Alarm Triggered by Sensor for Anti-theft Alarm System: Static - Closed
01462 Anti-theft Alarm Ultra Sonic Sensor (G209): Sporadic - Power supply too small

-----------Cent. Conv. System:

01330 Central Control Module for Central Convenience (J393): Static - Faulty
01330 Central Control Module for Central Convenience (J393): Sporadic - No define
01330 Central Control Module for Central Convenience (J393): Sporadic - Power supply too small
01565 Luggage Compartment Light (W3): Sporadic - Short circuit to positive
01581 Incorrect Component Detected: Static - No indication on display
01134 Alarm Horn (H12): Sporadic - No communication
01616 Signal Wire to Interior Monitor: Sporadic - No communication
01616 Signal Wire to Interior Monitor: Sporadic - Short circuit to positive
01370 Alarm triggered by Interior Monitoring: Static - No indication on display
00962 Alarm via. Tilt Sensor: Static- No indication on display
01368 Alarm Triggered by Luggage Compartment Switch: Static - No indication on display
01369 Alarm Triggered by Hood Switch: Static - No indication on display
01374 Alarm Triggered by Terminal 15: Static - No indication on display
01371 Alarm Triggered by Door Contact Switch Driver's Side: Static - No indication on display
01572 Alarm Triggered by Door Contact Switch Passenger Side: Static - No indication on display
01574 Alarm Triggered by Door Contact Switch Right Rear: Static - No indication on display
01534 Alarm Triggered by Door Contact Switch Left Rear: Static - No indication on display (This is the door that will not lock)
01373 Alarm Triggered by Radio Ground Contact: Static - No indication on display
01384 Alarm Triggered by Glass Breakage Sensor: Static - No indication on display

There you have it folks, took me way too long to get that out neatly as I could haha. To be fair I have not seen this many codes on the vehicle when I scanned it before when I've had alternator and key fob issues (the key fob issues are still ongoing mind you). Some of the power supply codes I've noticed "tend" to come up after my battery has been drained, but nonetheless could still be a sign for replacement (which I already purchased one today as well). So any ideas lay em on me.

[diagnosticator]

Those fault codes may not be associated with the symptoms you described as occurring now. They may be old codes stored before. Clear all the codes and see what codes are recurring again now.

[diagnosticator]

It's probably one of the doors not registering as closed that's setting the alarm off. Either that or the hood or trunk is not registering as closed. Unfortunately without the codes there's not much you can do. This was happening to me when my hood latch wasn't registering as closed and the alarm would sporadically go off.

If there are any door or hood latches that are not being detected as closed either being open or from a faulty latch switch, the alarm will not arm when the car is locked. This unarmed alarm state is indicated by no alarm horn chirp and no parking light flash when the car is locked. If the alarm can't arm due to a faulty door or hood switch, the alarm will not sound off after the car is locked, since the alarm will not be armed.

[renold458]

I'll erase em. Just report back with whatever stays in the system right?

[diagnosticator]

I'll erase em. Just report back with whatever stays in the system right?

Yes, if any of the displayed DTCs are old, erasing them and seeing what DTCs reoccur will help reveal what is relevant now.

[renold458]

So the codes that remained were 01274 Air Flow Flap Positioning Motor (V71): Sporadic - Blocked or without voltage in the HVAC system, 01304 Radio: Static - No communication in the Instruments, and every code in the Cent. Conv. System.

[renold458]

Any luck figuring those codes? Anyone know where the CCM is in a 2002 Audi A4 1.8? With more searching (and the CCM code), my assumption is pointing to a bad CCM where it could've been water damaged.

[diagnosticator]

Any luck figuring those codes? Anyone know where the CCM is in a 2002 Audi A4 1.8? With more searching (and the CCM code), my assumption is pointing to a bad CCM where it could've been water damaged.

The CCM is in a box under the driver's side carpet, forward of the seat. The CCM is often damaged if water gets into the box from a leak from the plenum.

[renold458]

The CCM is in a box under the driver's side carpet, forward of the seat. The CCM is often damaged if water gets into the box from a leak from the plenum.

I finally grabbed a new CCM from the junkyard (hopefully it works). Parts and model numbers match up as I grabbed it from a 2002 1.8T. Mine doesn't seem to be water damaged but might as well do the swap and see what happens. Will I have to reprogram it for my car?