jesse7flying

Hi All,
Did a cursory search and found nothing helpful, so here goes. My 01 Carrera recently developed a weird problem with the central locking unit where it turns itself on and off at will. Sometimes when I hit a bump in the road, I hear clicking under the driver's seat and then the accompanying two beeps of the horn. Kind of annoying when in traffic and the horn starts to beep. Today it just started beeping while parked at Starbucks.

This had been going on for a while and I tried to chase down the issue, but decided it was a bad battery. Replaced the battery and all was good for a while. Now the beeping has started again. Is there a known issue with the central locking module, which I assume is under the driver's seat? I don't think the car ever got wet enough inside to affect the module. I don't see any codes on my scanner. Any help would be appreciated.
Regards--Jesse
PS--I've disconnected the battery while I do some thinking on this.

De Jeeper

So there is a horn and an alarm horn. U can disco the alarm horn as its under the plastic cowl by the brake mc linkage. I would do this first. Not sure why it would be going off but ecudoctors can fully test the imobilizers.

Optionman1

I found this with a google search. Not sure if this is your problem or not. Good Luck.

https://www.porscheclubgb.com/forum/tm.aspx?m=996917

Optionman1

or this:

https://www.renntech.org/topic/1728-horn-problem/

jesse7flying

Thx for the reply guys. I looked at the horn ring issue Optionman1, but I don't think it's that since I had already discoed the main horn and I was still getting the double beep. My problem, I think, is with the central locking alarm horn as pointed out by De Jeeper. I think the problem is with the module under the driver's seat, but I'm open to any other ideas. Thanks again.
Jesse

Porschetech3

Take the 4 seat bolts out and lay the seat back and remove the alarm module...takes about 10min...
Open the module up and look for moisture or corrosion.... this is a very common issue....even when people "think" it hasn't been wet..

If ok then you need a PIWIS to trouble shoot the alarm system, it will list what circuit/component caused the last "trigger" of the alarm system..aftermarket radio with a "loose anti-thieft wire" is a common cause also...

jesse7flying

Thx P-tech 3. You are correct. I have no idea if the thing ever got wet before my ownership period. Just as an aside, ECUDOCTORS indicated that corrosion in the module is in essence, a ticking time bomb and attempts to clean it up would just delay the inevitable failure of the module. They would recommend outright replacement of the module. I can see the logic, but the $1200 cost of replacement is a bit much to swallow for me right now.
in the meantime , I will pull the module and open it up as you recommend. Now, if I could just find someone with a PIWIS...
Appreciate the input.

Porschetech3

Come back and let us all know the final outcome, to put a close to the technical thread......

jesse7flying

Sorry for not checking in again. Life has gotten in the way a bit. I pulled the seat, cleaned up the grounding point and pulled the module. There was no evidence of any water damage in the area, the grounds were not bad. Typical 20 years worth of slight corrosion. I opened the module and the board looked pristine. I inspected for cold or broken solder joints and found none. No strange looking components on the board. I pulled the 15 amp mini fuse from the board and cleaned up a bit of corrosion and reinstalled it. Put everything back together and I saw the central locking button lit up with the red dot when I started the engine. I tried to turn off the light, but it would not. Did not have a chance to drive the car, hopefully today. I will report on any progress. Thx
Jesse

jesse7flying

Finally had a chance to drive the car for a while to and from our local C&C, about 65 miles round trip. Car did great, no clicking from the module under the seat. Talked to the owner of the local P-car repair shop which sponsors the C&C, explained the issue, what I did to the car and the module and he agreed I had done about everything I could and done it correctly. I might still try to schedule some time with one of his 996 gurus to put the car on the PIWIS and look at any underlying issues. For now, I claim victory! Thanks for all the inputs, I really appreciate it.
Regards--Jesse