Remote central locking / alarm issue

ABC · Post by **ABC** » 24 Sep 2018, 10:48

Hello

I've had this car for years and the alarm has never sounded. The hazard lights would flash if activated but no sound. I've always suspected the siren battery as the sunroof recently gave up and I think that they are linked.

Before I got to fit the new siren battery I bought a further problem occurred.

I parked the car one day and locked it on the remote and the alarm went off upon locking! First time I had heard in 7 years. I opened and closed the doors and all ok.

After sometime this became a intermittent fault then permanent so that I could only "unlock" remotely.

At the moment the remote does not work at all (so no alarm activations either), although there are no problems using the key.

Any ideas anybody on how I can get the remote working again?

Thank you

Post by **SuperHerman** » 24 Sep 2018, 11:01

As I understand it they are all tied to the siren module, but I thought the remote should work.

Remote not working - have you checked your FOB battery?

You want to get that siren module out ASAP. The longer it sits the more likely the battery acid will destroy it beyond repair. The modules last about 5-7 years before the internal batteries go and start to leak. As they leak start to leak the acid starts to eat the circuit board. Caught early enough only the battery needs to be replaced (which is a project in itself as the siren is sealed).

Post by **ggleavitt** » 24 Sep 2018, 15:46

The Siren Control Module and Sunroof Module power and communications lines (LS-CAN) also connect with the UEM. The UEM is the module which communicates with the remote (and in turn communicates with the REM to engage locks and arm the siren module).

Best to get the siren module replaced if it's bad. Had same scenario as above (with battery juice leak onto PCB) occur in 2013 on my '05, replaced the siren module with new and all is well since- https://forums.swedespeed.com/showthrea ... ost2214741, link includes a few references as well.

Edit 092418- Add MVS post with wiring diagrams- viewtopic.php?f=10&t=86388

ABC · Post by **ABC** » 25 Sep 2018, 01:35

Thanks, good advice. I don't want a leak

Post by **ggleavitt** » 25 Sep 2018, 09:31

That you had partial functionality and now no functionality, I suspect battery leaking onto PCB has already occurred. Good news is the unit is sealed as noted above so no caustic battery juice will get on the car. Replacement is pretty straight forward, my guess is once the unit has been swapped out everything will go back to normal.

Good luck !

**Link for someone who has done a repair versus replacement-

edit 092518- Add **link