alarm goes off every time after 25 minutes

[porsche356]

Hi,

My 4s has the alarm going off everytime after 20-30 minutes. Everything is closed and I can't think off a reason why the alarm does not go off emediately but everytime after 30 minutes. I also have a problem with my PCM overheating. Is there perhaps a relationship between these two issues?

Best regards, frank

[RFM]

Inside battery in the siren could be the problem ( ROW - Netherlands )

[TcomBrat]

Hi,

My 4s has the alarm going off everytime after 20-30 minutes. Everything is closed and I can't think off a reason why the alarm does not go off emediately but everytime after 30 minutes. I also have a problem with my PCM overheating. Is there perhaps a relationship between these two issues?

Best regards, frank

Did you try manually locking the car w/ the key

had this issue on my Cayman S on Sun and that was the solution

just manually insert the key and lock the car

if this works i'll tell you the reason why you had this issues

good luck

[porsche356]

Inside battery in the siren could be the problem ( ROW - Netherlands )

is there a way to check this RFM? The car had a completely dead battery and the replaced it this morning.

Edited November 14, 2008 by porsche356

[porsche356]

Hi,

My 4s has the alarm going off everytime after 20-30 minutes. Everything is closed and I can't think off a reason why the alarm does not go off emediately but everytime after 30 minutes. I also have a problem with my PCM overheating. Is there perhaps a relationship between these two issues?

Best regards, frank

Did you try manually locking the car w/ the key

had this issue on my Cayman S on Sun and that was the solution

just manually insert the key and lock the car

if this works i'll tell you the reason why you had this issues

good luck

I am quite curious what you are aiming at! I will try this tomorrow. I'll let you know a.s.a.p.

Regards, frank

[porsche356]

I did some small testing (did not try the locking with the key yet TcomBrad, but will do so today).

Found out that the alarm does not go off when I double click when I close the car. The manual says that this will turn off the passenger sensors. Does this mean that there is something wrong with one of my sensors? (there are no flies in my car, so that can't be the cause' :rolleyes: ).

Are there anymore changes to the alarmsystem when the 'double close' feature is being used? Where are the sensors located? Can I run some tests on them?

Best regards, frank

[RFM]

Use your diagnostic tool to read and the code and clear. Death battery's can give odd things on ROW alarm systems, if there is something wrong the fault will return quickly.

[vizcarra44]

Hi from across the pond,

this is a problem with your radar sensor in your center console, very common problem.

Ciao B)

[TcomBrat]

Frank

Here is my post from the Cayman club website.

I really think the issue was some kind of an interruption

I hope you where able to solve your problem

This happened to me last Sunday. I was at the mall parking lot and after locking the doors with the remote alarm started within 3 minutes or so. I unlocked the car and relocked it same thing. I started the car then turned it off same issue. I was only going to spend maybe 30 minutes at my destination and I was at a pretty good area so when this happened the third time I pressed on the lock key and unlocked the car walked away like it was locked. I was little worried but everything was ok

Got home read the manual and it indicates that sometimes external signals such as radio ect can disrupt the IR signal from the key.

I’m not sure if I had the radio on or maybe the navigation or something before I left the house but something disrupted the signal.

I’m thinking this is an extra added security on the keys if someone is trying pick up the IR signals of the key while you are locking your car the car never really locks

So anyway

Solution:

I read in the manual when this happens manually lock the car with the key and I think this confirms that you are opening the doors with the actual key.

This resets the issue.

I haven’t had any issues since Sunday.

I hope this resolves everyone’s problems

Thanx

[porsche356]

Hi from across the pond,

this is a problem with your radar sensor in your center console, very common problem.

Ciao B)

Hi Vicarra44,

thanks for the reply. Do you perhaps have a solution for this very common problem. Can I check certain things or do I need to fix/change something?

Thanks, frank

[berty987]

Netherlands and UK vehicles have additional security to other countries. The additional items are a battery backed siren and tilt sensor. If the battery has died , then the battery in the back up siren will discharge too. I have heard of issues with false triggering of alarm systems on 986 vehicles (which use the same manufacturer for the battery backed siren ) after a full battery discharge. False triggering from the internal microwave sensor can be caused by metal objects in the center armrest , this is also something to check. The internal contacts that feed into the alarm system are the glove box, the doors and the front and rear trunk covers , as well as the covertible top home position. If one of these additional sesnors has a bad contact this can also cause problems. Turning off the interior microwave sensor by double locking may prove or disprove that the inerior microwave sensor or glove box contact is at fault.

[porsche356]

Netherlands and UK vehicles have additional security to other countries. The additional items are a battery backed siren and tilt sensor. If the battery has died , then the battery in the back up siren will discharge too. I have heard of issues with false triggering of alarm systems on 986 vehicles (which use the same manufacturer for the battery backed siren ) after a full battery discharge. False triggering from the internal microwave sensor can be caused by metal objects in the center armrest , this is also something to check. The internal contacts that feed into the alarm system are the glove box, the doors and the front and rear trunk covers , as well as the covertible top home position. If one of these additional sesnors has a bad contact this can also cause problems. Turning off the interior microwave sensor by double locking may prove or disprove that the inerior microwave sensor or glove box contact is at fault.

Hi Berty,

I do have some keys in my centerconsole, but this has never caused any problems with my 997 cab. Because the alarm only goes off when I turn on the internal microwave sensors there must be something wrong there. The car is scheduled for service anyway, so the dealer can use the PIWIS to see which sensor is the bad one.

Thanks, frank

[berty987]

The internal microwave sensor is only activated if the car has the roof closed on a cabriolet. If its a tin top then the solid roof may allow for better and more sensitive zoning of the sensor. Certainly the sensitivity of the sensor on my boxster is not particularly high. The microwave sensor sits just back from the handbrake under the center console. Sounds more like you may have an issue with the battery on the battery backed siren . You could try removing the siren as its only an output device so there is no feedback to the control unit if its removed , just make sure the key is in the ignition before you remove it. A new siren will cost you less than half an hours tech time so it may be a cheaper option.

[drchrism]

I have a 2000 Boxster S which also sets the alarm off after sitting for 20 to 30 mins with the top on and the alarm set but only in the day time, never at night. I tried locking the doors manually with the key but still got the same results. My dealer said the possible problem was heat related, so I started leaving the windows down one half inch when I set the alarm and no more false alarms. That solved the symptom but does lead me to the diagnosis of the underlying cause of the problem.

Good Luck,

Dr C

[vizcarra44]

Is this car still under warranty? At this point its kind of playing tag your it. If you have access to the factory Piwis tester you can look under the PAS module and see recent alarm events, this will show you what caused the alarm to go off. Like I said, here in the states its usually just the radar sensor, dont know about the euro spec alarm systems.

Good luck :P