Alarm causing lockdown condition?

[dmsexton]

Hey guys.
Our '03 X5 has lost key fobs, central locking and interior lights. This is the second time it's happened. We just had this condition and I had the GM3 module repaired by Scott Johnson @ BMWG 5.com. Everything worked great wafter we got it back, and then my wife had the car and the alarm apparently had activated (lights were all flashing) and we lost key fobs, central locking and interior lights again!
So little history, the PO took the car to a local Independent dealer for "alarm randomly going off" and that dealer told me they "disconnected" it. But I believe all they did was disconnect the audible alarm portion, or that's how it seems because the horn doesn't honk when you lock the car or if the alarm is activated, but the light still flash.
Is it possible that the alarm is to blame, that it's causing a sort of "lockdown" so I'm losing all those things if the car thinks someone's trying to take it?
I've read about "transport mode", but we know this time everything was fine until the alarm went off, and then we lost it all, and that was the same thing we had before I had the GM3 repaired.
I really don't know where or how to troubleshoot this.
Thanks in advance!

Dave

[Qsilver7]

It sounds like you really need to have the vehicle hooked up to BMW DIS (or the aftermarket software/hardware) so that you can communicate with ALL of the car's modules...and find out if any faults have been set by systems. This will point you in the right direction for a better diagnostic situation.

There are 3 different systems involved in the scenario you're describing. All 3 systems work independently...as well as in conjunction with the other 3. And because FZV & DWA share some of the same monitors...it may seem as if they are one system...but they are two different systems...so you need to try to divide...so you can conquer which one may be acting up:

• EWS - immobilizer, cancels ignition, fuel, starter if transponder chip in key doesn't have the same ISN (individual serial number) that the EWS control module & DME/ECU has
• FZV - central locking system...allows lock/unlock of the doors & trunk from a central location (button on ctr console or remote key or driver's door lock cylinder)
• DWA - anti-theft alarm siren system...includes monitoring of all the doors, trunk/tailgate, hood...plus an IMS (interior motion sensor) and TILT sensor...and has a red status LED and, of course, the alarm siren.

The DWA system uses an audible & visual alert for arming/disarming...and yes, you can have multiple combinations of what you want activated. It sounds like the audible arm/disarm alerts have been turned off in your description...but the visual alerts were left on. But when you lock the vehicle (from the driver's door or with a remote key)...take a look at the red status LED to see what the system is doing:

The FZV (central locking system) uses the same door monitors as the DWA system...so if you use the chart above and you have open monitors (fast flashing for first 10 seconds)...then you may have an issue with the door actuators...this is where divide & conquer comes in...separating if the issue is DWA or FZV related.

Also, both FZV & DWA use the same 315 MHz radio frequency (in North America) being emitted from the remote key...it is picked up by the FZV receiver using the antenna built into the rear left side cargo window...the receiver is in the top center of the lift gate. The signal is then processed and sent up to the GM where the GM sends orders to the FZV system to lock/unlock the vehicle...and to the DWA system to arm/disarm the alarm system.

{the diagram below is of the e39 Touring...but the Tourings and SAVs/SUVs utilizie the same antenna design}

[dmsexton]

Qsilver7, that is an awesome amount of information! Thanks for taking the time to write that all down!
Good news for us, the car is ok (for the most part). My wife was mistaken in thinking it was all not working after we got the GM3 back. Basically, I just needed to resync her key was all.
The bad news is the alarm continues to randomly be activated in the car, or so I believe (at random times and places, when we come out to the car all the lights are flashing). That is something I have yet to figure out why it is happening. I do know it was taken to an independent dealer here in Honolulu for exactly that complaint before I owned it. We may just learn to live with that condition as I believe it would be cost prohibitive to have that troubleshot.
In the meantime, it is not time to tackle the oil leaks, power steering and coolant leaks...

[Qsilver7]

Good luck...but just to throw it out there...some BMW models have a common issue with the hood alarm switch or the fuel filler flap door causing false triggering.

The hood alarm switch can be unplugged...and if the false triggering stops...then you've found your culprit. You can then leave it that way, or replace it...or determine why its false triggering. The e53's hood switch is located near the windshield on the passenger side of the engine bay:

The fuel filler flap can be checked by locking the vehicle using the key manually in the driver's door lock cylinder, or by locking the vehicle with the remote key. This puts the car in "double-lock"...thus the fuel filler door should be locked. Walk around and check it. If it can easily be opened due to it not being locked...then you have an issue with the fuel filler door actuator. It too can be unplugged...then check the rear fuses to see if the fuse back there is blown for central locking. If it is, replace it then check if the system starts working again. Again, you can choose to leave it unplugged and the DWA system will ignore it but yet still arm the vehicle and the other "monitors".