Central Locking Issue and Alarm

[Sarnian10]

Hi Guys,

 

Im trying to pick my way through a number of issues on a 1999 Carerra 4 996.

 

I had a new battery installed but it would appear that i have a power drain as im having to charge it every couple of weeks. Im going to have this new battery tested just incase its faulty.

 

My main issue is that the alarm keeps going off randomly and always at silly O'Clock at night. I have read through hundreds of pages of information and threads but I have slightly different symptons. The alarm goes off randomly. The central locking also has a fault which im trying to diagnose.

 

I leave the car unlocked and still the alarm goes off, i get a single beep of the horn when locking and a double when unlocking which i have found some info to work through but i really need to stop the siren going off. Does anyone know where the alarm siren is located (not the horn next to the battery as i have done that and that just stops the alerting beeps not the siren). I really need to disconnect the alarm siren!

 

Any help greatly appreciated.

 

 

[DBJoe996]

I don't think a 99 996 has an alarm siren.  When the immobilizer is set off, it just beeps.  Are you sure there isn't some aftermarket alarm on the car.  A beep when  locking the car means a zone is open somewhere....hood, engine lid, console lid, fuel filler door, doors, overhead infrared sensors, and if you have it the glove box door.  If the car is unlocked and thus the immobilizer is not set, and yet the alarm is going off you have a problem.  Pull the fuses for the alarm system B8 and C3

 

Edited August 15, 2019 by DBJoe996

[JFP in PA]

59 minutes ago, DBJoe996 said:

I don't think a 99 996 has an alarm siren.  When the immobilizer is set off, it just beeps.  Are you sure there isn't some aftermarket alarm on the car.  A beep when  locking the car means a zone is open somewhere....hood, engine lid, console lid, fuel filler door, doors, overhead infrared sensors, and if you have it the glove box door.  If the car is unlocked and thus the immobilizer is not set, and yet the alarm is going off you have a problem.  Pull the fuses for the alarm system B8 and C3

 

 

It is a UK car, which came with sirens, which also had their own batteries, which is probably the issue here. The black box is the siren, the lower box is a tilt sensor, which is apparently well known for causing problems.  The unit sits next to the main battery, under a cover.

 

 

Here it is out of the car:

 

[rramos439]

Are you locking the car? If the car is not licked it will drain the. Attery. I had that same problem

Sent from my SM-N960U using Tapatalk

[hardtailer]

I have two symptoms similar to yours:
1. My battery is drained after 2-3 weeks of  sitting locked. I tend to think the drain by the alarm system in the first 5 days of sitting (after that it switches to a less power consuming mode) causes this.

2. I have one beep when I lock the car and as stated above it means one zone is found open. Apart from the already mentioned ones there are two more (as I learned over at rennlist.com).
One is the switch behind the OEM radio that breaks the circuit as soon as the radio is pulled out or its connector pulled off.
Apparently isolating the/a brown ground wire and leave it disconnected solves that when fitting an aftermarket radio.

The other 'zone' is the actuator that locks the manual levers to open trunk and engine lid when locking the car using the remote.
I found in my 99 Carrera 2 that the locking actuator was not fitted and it looks it never has been as the actuating rod and associated plastic clips n guides are absent too.

Looking at 2nd hand parts online I am not sure every 996 up to 00 came with this actuator even though the parts catalogue states so.

 

See pictures below for the associated parts.
A way to check whether that is the open zone is to open the trunk, push its lock to the closed position using a screw driver, get access to the battery poles, lock the car via the remote. (You should get a single beep if you successfully locked the trunk lock else two beeps)
Disconnect the positive battery wire, open the car with the key and pull the trunk lever. If the trunk lock snaps open then you either have no actuator locking the levers or it is broken (in the open position) and the single beep stems from it being broken.

 

Cover removed from sill (on LHD car) yellow lines mark locked and open position

The actuator fits on the right side of the alloy bracket.

 

 

Being a UK car it has to fulfill Thatcham anti-theft requirements which probably had porsche fit the siren and tilt sensor shown above that is different from RoW vehicles. 

Edited August 16, 2019 by hardtailer

[Sarnian10]

Thanks for the help guys, really appreciated.

 

The battery has been tested today and is fine so I have a drain on power somewhere. The alarm goes off whether locked or unlocked.

 

I have followed the instructions for determining faulty micro switches and all doors appear to working correctly, the fuel cap locks, I will check the solenoid for the Frunk lever.

 

Today seems to be working normally so will keep an eye on it but when driving away it would auto lock but sound like it’s doing the sequence twice, then when pressing the lock button on the dash (red light on) it would cycle twice and honk twice.

 

The car was parked up for about 7 years in a barn so I’m hoping might be some sticky contacts?

 

i will have a look for the siren today as I’m in Guernsey and not worried about theft so will disconnect it for now.

 

thanks again, last night I disconnected the battery and had a quite night!

[JFP in PA]

3 hours ago, Sarnian10 said:

 

The car was parked up for about 7 years in a barn so I’m hoping might be some sticky contacts?

 

 

I'd also be looking for wires damaged by mice.

[DBJoe996]

Recently had my drivers side door latch mechanism begin to do weird things.  Lock..okay.  Unlock and lift door handle...nothing.  Repeat and it would do it again.  Finally, when I could lift the door handle to open the door, often the door locks would begin to cycle on and off and the lock button on the dash would flash red then off, then on again.  I finally replaced my door latch mechanism entirely with an OE Porsche part.  No more problems.  The door latch mechanism has three microswitches on  it, one internal on a circuit board inside the door latch.  The door latch mechanism is an electro-mechanical device.  Apparently when the door latch mechanism goes bad (one of the microswitches), the car does all sorts of weird things.

 

My car is 21 years old with 144K miles.  I accept that things are going to need to be replaced at that age.  I daily drive and sometimes lock/unlock 5-6 times a day.

Edited August 16, 2019 by DBJoe996

[B3-CPO]

On 8/15/2019 at 6:18 PM, rramos439 said:

 If the car is not licked it will drain the. Attery. I had that same problem

 

 

I have yet to lick my car and the battery is just fine. 😂