E30 Zone

I have a Sepristar 480 (I think) fitted to my 325i.

Today I blipped the fob to open the doors and within about ten seconds all hell broke lose with the alarm. It would not shut up for about 15 minutes whatever I did.

Having left it to calm down for about 15 minutes I went on my way. When I got to my second stop, all hell started again, and was eventually cured by getting out of the car and blipping the fob to lock it.

About three hours later (now about 11pm at night), the alarm goes off again, although this time it was just sitting there locked.

I have managed to shut the bugger up for now, but any advice as to what this, or what I could do about this, would be much appreciated. I don't think my car is going anywhere until I have this resolved.

I don't know how to help you fix it but i can suggest that you can just unearth it .

thats how i disconnected mine when halfords broke my keyfob....

i just deadlock it and keep nothing valuable in the car

Could be an oversensitive shock sensor or the alarm may be detecting a voltage drop which causes it to trigger. You should try to get a manual for the alarm and see what features it has. Could be it just needs to be adjusted. The manual should be able to tell you if the alarm cycle is 15 mins, i.e. it sounds for 15 mins after it is trigerred. If so, it could be a single event that triggers the alarm which then runs for 15 mins rather than something happening for 15 mins that is triggerring the alarm (hope I'm making sense here )

Any ideas on how to test for a voltage drop?

Kevin: I get what you are saying re. the running for 15 minutes, however I am not sure how this could be occuring when the alarm has already been deactivated. I understood that once deactivated, only the immobiliser would kick in if the car was unlocked (at least this has been my observation of leaving it open for a couple of minutes).

Everything would make sense if this occured only when the car was locked, so the alarm would be armed, however it is occuring when it open as well as when it is locked.

I am starting to think I might have to take this to a garage if I cannot find anything obvious.

Sorry Alwyn,

I misread your post. Are you certain the keyfob is deactivating the alarm when it unlocks the doors? Perhaps the alarm is remaining on even after sending the unlock signal to the cars central locking?

How would that sit with the alarm going off more than three hours after the car had been locked? (i.e. the final time it went off).

Are there easy ways to check if this is happening? For example, is there any change in what the indicator lights, and also the immobiliser light, will do?

Where should I be looking for the sensor for the signal to deactivate the alarm?

A dodgy (old) back-up battery inside the alarm can cause false triggers. Had a simillar problem with mine, opened the sounder unit, found battery was defunct and had leaked all over the circuit board.

My thinking is that the alarm is not deactivating or is reactivating itself for it to trigger and sound after you have opened your doors with the keyfob. And if it is also going off for no apparent reason when it is activated, then it sounds like some sort of internal fault in the alarm unit, perhaps like what alex-is has mentioned above or maybe some moisture has gotten into the unit.