alarm issues

For some reason i got up this morning and i couldn't open the car with the key fob using the alarm button. [ ]All efforts failed which ended up with me having to open the car with the key in the door. [8|]Needless to say the alarm went off [:'(]until i put the key in the ignition. Any ideas!!!! I think the neighbours will soon get fed up with my alarm going off...The red led lights bright enough on the key fob. Any advice would be appreciated. By the way Richard, sorry i didn't respond earlier but are you able to forward the details for fixing the window regulator (see post 18/11/07), my e-mail is [email removed] Thanks

When did u last drive it? They automatically shut down the fob activation after 5 days I think it is. Then only the key will unlock it but if you press fob immediately after unlocking door with key it will all be ok again and reset.

What Neil said..... BTW, I sent the window instructions to the freeserve address, which you must have set in your profile. I've forwarded it to the other address, so you should get it in a mo.

I would see what happens after the battery has had a good charge. Low voltage causes all sorts of alarm issues. I can't remember what year your car is, but if it is pre-2001ish, check that the alarm tilt sensor isn't filled with water, which is a common source of false alarms. It is located under the cover to the right of the battery as you look at it. (The box with the white sticker in the pic).

My alarm always tends to go off as the battery drains towards flat so I've always got it on a trickle charger now. I've always assumed it was designed that way in case anyone is trying to cut the power to silence the alarm in order to steal the car. I believe the alarm has its own battery to keep the sounder going.

Thanks for your replies. Car will stay on charge overnight, and I will check the tilt sensor in the morning, as the car is 1999.

Turn ignition on in the few seconds before the alrm goes off after unlocking car? DJ

If it is like my '98 C2 was, it went off as soon as I turned the key in the door. I never found a way round it.

I didnt think there was a solution. Why isnt it as simple as other cars where you simply remove a fuse.

I have had the same problem (remote not working despite battery changes) for a while but fortunately do have a few seconds after unlocking before alarm goes off so I can switch the ignition on and disable the alarm. All the other locks remain on though (fuel cap, boot and passenger door) which can be a pain but I suppose has not been enough of an issue so far to be in a rush to get it fixed. DJ

If it's getting sluggish then it might be time to change the battery - if it's the Porsche fitted "Moll" brand then they seem to fail pretty quick after first symptoms appear. If it's the Moll battery then how old is it, and have you ever topped up the cells? They do need it now and again.

This my first winter with it so I don't have any point of reference. But I'm aware that new cars do drain batteries quite quickly. Is the cigarette lighter live with the engine off (for the accumate)?

Alarm problems are generally a symptom of incipient battery failure Richard. If you're not using the car regularly, I'd keep the battery on the AccuMate. It's only a minor faff to connect/disconnect; and you should avoid possible complaints from the neighbours when the alarm goes off..! The cigarette lighter on my 987.2 Cayman is always live, but it may be different for your car; easy to check. Personally, I prefer to use the croc clips to attach my ctek to the battery after I had problems connecting via the cigarette lighter module. Jeff

I would echo Mark's comments completely. Is it a Moll, and how old is it? Anything over about 4 years and you are living on borrowed time. The ciggie lighter socket on your car should be permanently live. It was the earlier pre-facelift 996's which were ignition-switched.

Thanks everyone. I'll have a look at the battery tonight and put it on charge. Its an 03 (04MY) so hopefully permanently on lighter. I can put a solar conditioner in and just plug that in as I park up.

It turns out it is a Bosch Silver battery so I've put it on charge. I'll see how it goes.

Had Bosch Silver batteries on my old 911SC (very little use - 1500 miles a year) - none of them lasted less than 8 years. Also seemed to survive the odd long (accidental) deep discharge.

You really need to know exactly what is setting it off, so getting it plugged in to a Porsche tester is the best way of diagnosing the problem. That said, the two common causes of random false alarms are the interior monitoring sensor (near the rear view mirror) and the tilt sensor (on a '98 car, to the right of the battery as you look at it). Take a look at the tilt sensor and see if it is full of water. You can see the tilt sensor under the black/red alarm siren. Disconnecting it (remembering to switch on the ignition before you do so) might eliminate it as the source of the problem.

Thanks Richard, will look into tomorrow.

Charging the battery is one thing, it holding the charge is another..... have you had any issues with windows lowering or the rear spoiler coming up? Strangely, this does happen when battery is faulty & obviously depletes it further + it triggers the alarm siren....

i suggest a new battery

Hi, thanks for your response, however battery is fine and no issues with windows. Spoiler is a fixed GT3 dual blade.

The battery remains the most likely culprit. What happens when your battery charger is attached to the car? If that cures the problem it would confirm the battery is the issue. If not it will be an alarm unit fault.

I would suggest temporarily disconnecting the tilt sensor and siren. It might be that the siren backup battery is low/failing, or the tilt sensor has water ingress. Switch on the ignition before disconnecting. You will probably get a single beep on locking, but at least it might eliminate these devices from the possibilities.

I had this a year or so ago, alarm would go off for no reason , locked or unlocked , as Richard has said the tilt sensor gets moisture in it , so I took mine out and removed the alarm siren too. Everything still works fine , locking / unlocking etc. I did contact my local OPC , evidentiary there is a upgrade tilt sensor available that is repositioned under the passenger seat and I think the kit cost was around the £350 mark. The original one is next to the main car battery , which I’m sure you know already ! 75PNO

Thanks Richard and 75 pno. As I stated earlier it's definitely not the battery as it holds 12.9 volts and was fairly new when I laid the car up. I know things can play up once the battery drops below 10volts but this issue is a new one. If I put the key in position, disconnect battery then reconnect and start the car, everything is fine. However, as soon as I switch the car off and remove the key I get a beep and the alarm sounds. At this point nothing can switch it off. If I try to put the key back in the ignition, if I set the alarm with the key fob and then set the alarm off.....nothing works with regards to cancelling the siren. Only goes off when disconnecting the negative terminal. The whole issue therefore starts when I remove the key from the vehicles ignition switch. i will look at removing the tilt switch and siren and give a clean but with this latest information do you think it can be anything else. As I say, it is triggered when I take the key out of the ignition switch, thanks

Hi Richard, I've just posted an update on the alarm issue to see if you feel it can be anything else. However, you mentioned siren back up battery. Is this on the siren itself? If not, can you point me in the right direction please. I will have a look tomorrow, thanks

Forget that Richard, just took off the backup battery box. It does have 4 screws but is pretty much a sealed unit so I'm assuming the whole thing would need replacing. The tilt switch box also looks to be a sealed unit. Apart from cleaning contacts there's not a lot that can be done with either I suppose

The backup battery is inside the siren itself. I think that the backup battery voltage may be too low, and when you remove the key from the ignition it "thinks" it is being disconnected and sounding. Cleaning it probably won't do any good, but if you disconnect it (with the ignition on) it might at least eliminaate it as being the culprit.

Guys, had both the siren battery backup out and the tilt switch. As I said earlier, both units look pretty much sealed. Contacts to the tilt switch were shocking. Green and difficult to clean. However, contacts cleaned as best as I could and 'hey presto' success. Hope it lasts this time. ive always wondered if my unit was. Sat correctly in the car ever since I bought it years ago as the bracket that holds it all has always looked bent. The rubber shock absorber at the bottom was always in the middle of nowhere so while I was fitting it back I bent th bracket so the shock absorber was touching the bulkhead where I think it should be. Let's hope it all remains working before the neighbours start complaining. Many thanks for all your help again. Stay safe

Excellent news re your fix & at no cost apart from your time..... a good point of reference for all us 996 er's should we ever experience similar....... Thanks for posting your +ve result

Cheers Kasspa, I attempt almost anything when trying to fix faults. However, would not be able to solve much if it wasn't for the advice I receive on this forum. It is always my first point of call and over the years have been very appreciative of everyone's comments, in particular Richard. Just got to refurbish wheels now and look at getting it on the road for the summer. All serviced and just about ready to go

Yes, what would we do without Richard's amazing knowledge..... [ ][s3] I must admit my 4S has been idle despite never SORNED & am eager to give her a 'blast'.....

Back again with the annoying alarm issue as my fix clearly only lasted a short while. I've now removed both the siren and tilt sensor until I can decide the best way forward. Upon further investigation I have noticed that the tilt sensor box seems to have alot of water inside. How, i don't know as its a sealed unit. My suspicion is that this is possibly what is setting the alarm off. Has anyone tried to resolve this issue? Will drilling a hole in the bottom of the box drain off the water or has anyone opened up the tilt sensor box by cutting it open and then resealing it thus gaining access to the tilt sensor to enable a thorough clean? Many thanks

HI, Are you 100% sure the front drains are clear?

Yes, drains are clear. I'm assuming that the water/moisture in the tilt sensor box is so much that its interfering with the contacts etc.

Update...I believe my current tilt sensor part number 996.618.265.00 was upgraded to part number 996.618.265.01. However, during this upgrade porsche decided to make things difficult by ensuring the new unit required a different bracket and wire which connects the tilt sensor to the siren. So not only £230 for the tilt sensor but an additional £43 for the cable Nd £10 for the bracket....ridiculous. Anyway 1. How can I test my sensor to ensure that this is the issue and 2. Has anyone ever cut the tilt sensor box apart to gain access to the parts for cleaning and then resealed Any advice appreciated

Hard to see much water should get into the sensor box if the drains are ok as it's raised off the bottom panel, have you noticed much water there? could it be coming for a faulty windscreen washer jet tube (just a thought) I would dry the sensor out and put it in a sealed plastic bag and keep an eye out for water. good luck

Hi Richard, cleaned all connectors. Had to drill a hole in the tilt sensor box to drain out loads of water. Do you know if changing the battery back up is possible and finally, can the tilt sensor box be opened up in any wY to get at the inside for a deep clean. I'm coming up against a brick wall here with this one. Alternatively there are some second hand upgrades available but these require new brackets and connection wire. Thanks

Hi David I think you are bashing your head against a brick wall if the tilt sensor has flooded and the siren battery has expired. Both are sealed units, and you would have to cut the cases to get them apart. It might be worth trying with the siren, as you can probably fit a new rechargeable battry if you can get it apart. As for the tilt sensor, I would try and get a good used one from a breaker, or replace it with the later sensor that goes under the passenger seat. I have the wiring instructions if you need them.

@devans Did you manage to sort this issue in the end as I am having similar with my car? The tilt sensor also has water / liquid in it, but I was actually wondering if that is how the mechanism works to detect a 'tilt' - but it might just be caput and full of water but seems strange as it is a sealed unit as you say!