Greetings All

another day, another issue!

the alarm has been going off over the past few weeks randomly, but today, it’s really stepped up the game.

It stared screaming tonight, so I went out and unlocked he car, but it carried on. After a short while it stopped, but started again quickly.

I even tried starting the engine but it still carried on. In the end I disconnected the battery. It continued twice more, but not as loud, before stopping.

Is the a faulty siren? I did give the car a good clean, maybe water ingress!

the only other job today, was to replace a rear door handle, as the lock buttons have stopped working. Coincidence?

all and any help is always appreciated.

 

Sounds like it's an issue with the door lock. These cars have door locking systems best described as crap. I've replaced the front left hand door locking system a few times now, only to have it go faulty again. The alarm would sound if I locked the car because it couldn't work out if the door was open or closed/locked. Now I don't even bother locking it and had to disconnect the passive sounder because (like a smoke alarm, would start chirping at 2am).

 

You can use SDD to find out why your alarm is going off given time and frequency. It will narrow it down to which specific sensor triggered the alarm, usually a door lock actuator malfunction.

 

**UPDATE**

I've run a scan of alarm triggers using SDD and not all of them have been recorded. But.... The last 2 were Panic
Alarm trigger history.

I've turned the alarm sensors off in the car using the dashboard menu and swapped to the spare key.

See if that makes any imrpovement.

19:24:24 BCM Recent alarm triggers - event 1 Panic (0x12)
19:24:24 BCM Event trigger year 2025.0 (0x19)
19:24:25 BCM Event trigger month 3.0 (Month) (0x03)
19:24:26 BCM Event trigger day 2.0 (Day) (0x02)
19:24:27 BCM Event trigger hour 15.0 (Hr) (0x0F)
19:24:27 BCM Event trigger minute 9.0 (min) (0x09)
19:24:28 BCM Event trigger second 13.0 (sec) (0x0D)
19:24:29 BCM Recent alarm triggers - event 2 Panic (0x12)
19:24:29 BCM Event trigger year 2025.0 (0x19)
19:24:29 BCM Event trigger month 2.0 (Month) (0x02)
19:24:29 BCM Event trigger day 22.0 (Day) (0x16)
19:24:30 BCM Event trigger hour 21.0 (Hr) (0x15)
19:24:30 BCM Event trigger minute 58.0 (min) (0x3A)
19:24:30 BCM Event trigger second 55.0 (sec) (0x37)

 

It behaved itself for a week but unlocked the car yesterday to get thing out, no problem. 2 minutes after locking the car, the siren started. No lights. The unlock button on the key fob stopped it a couple of times but then didn't.
I even got in the car and started up, but the siren continued. I disconnected the battery in the end and it finally stopped after a while. Apparently the siren has a battery back up!

I've looked through the wiring diagrams and can not seem to find a fuse for the siren. I've ordered a replacement but its buried below the bonnet air bag.

I will update you all on the progress, when I get the parts.

 

I am guessing hood latch switch. You can bypass it with a jumper wire across the connections in the plug to see if that is the cause.

Mine acted like yours. I tried adjusting the switch but it eventually started acting up again. I jumped the connector and its never occurred since. Replacing the switch seemed stupid since it was overkill anyway.

 

Any updates? Mine has started doing the same. Intermittent, just siren no lights. Doesn’t reset even with engine running. Passive siren module … Any idea where it is? 2016 XJ. RHD Found location for XF XK but not XJ…
under windscreen in one post but unable to confirm what XJ this is.

Many hanks in advance, TS.

 

I’ve disconnected the siren and ordered a replacement from eBay.
it’s located below the bonnet air bag. It’s an easy job actually, just disconnect the battery.
when I fit the replacement siren, I’ll update but so far it’s been fine.