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Intermittent issues with lock/unlock button using key remote

Go to solution Solved by Silver_TT,

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2002 C4S (996).. I did a search but nothing definitive. Sounds like replacing the remote key worked for some people, and other people had luck doing otherwise or just didn't close their thread if they ever found a solution.

I'm experiencing the following which was never a problem until a week ago:

Sometimes the key remote opens/locks, sometimes it doesn't. It seems either that the remote device has an issue or it's somehow intermittently getting out of sync with the receiving unit in the vehicle. When I hit the button on the key I can see the light blinking on the key. When it's working I see the little red light on the vehicle dash receiver flash in "response". When it's not working I don't see the receiver flash at all. The lock/unlock button seems to only work intermittently. When the remote unlock does not work it seems that manually unlocking with the key, putting the key in the ignioion, then taking the key out and trying the lock/unlock button again makes it work again temporairly right away. The system works just fine when I use the key to unlock the doors the old fashioned way (manually using the key itself), etc.... so I'm thinking this is likely something more with the remote device in the key than it is with the central alarm and control unit within the car. If it is the remote key, what else could need to be replaced beside a battery? Can these remote devices in the Porsche keys just "go bad"? Strange that it's not just completely not working and does work intermittently still.

Some other notes:

- Durametric is showing no faults under "Alarm". (The only fault the entire car shows in any category is under "Seat Memory" and this hall sensor error has been observed by me in the past well before this issue surfaced, so I believe it's unrelated).

- I ordered a CR 2032 battery to replace in my key but I'm assuming this isn't the issue since the little red light still blinks just fine when the button is depressed. I will see if that works when it gets here in a couple days.

- The car came with a second key which I have never tried to use until this happened. This second key works just fine manually but the remote lock/unlock on it does not work at all (despite the fact that I see the red light flashing on the key).

Any ideas would be greatly appreciated. Thanks in advance.

Edited by ferrugia
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Good to know I'm not alone. Please post a follow-up if you are able to find a solution and I certainly will as well. I'm hoping this doesn't mean ~$300 to a dealer or someone with a PIWIS to reprogram. It was working just fine for the last year so I don't see what would have prompted this.

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Same problem here, with my 2002 C4S. Hmm interesting to note its the same age. Hopefully just the remote in the key going bad. I have 2 other keys which came with the car, where the remote doesn't unlock/lock the car even though the red light works.

When I did some digging I discovered that a new key was the only way to resolve this as I didn't have some long serial code number which comes with new keys and is (as I understand it) needed to be able to reprogram an old key with the alarm again.

Be interesting to hear other peoples experiences on this mysterious key issue.

Edited by Porca911
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My key fob stopped working 2 years ago. Did the same thing...intermittently working, flashing, blah blah, it finally gave up the ghost and stopped working altogether. It is the circuit board in the key fob. Not being interested in spending the money to replace the key fob and reprogram, I just use the key, lock/unlock the door and all is well. Been doing that for quite a long time now. No problems and the alarm is also set this way, so nothing to worry about. You're going to have to "invest" in a new key fob with the programming code (don't buy one off EBay), visit your dealer and have them set it up again. Then you can wait another 3-4 years before it craps out again...repeat and repeat.

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Thanks, Loren. My transponder is in great shape as far as I know. I had been thinking about getting the Design Key but when I called the guy in parts at Suncoast said he believes this is the housing only (in other words, no circuit board, etc). He said in order to get a new circuit board I need to buy a new key head for ~$100 and then the local dealer (or someone with a PIWIS) will need to program it. I guess what Loren is saying is this is not the case if the transponder pill I currently have is ok. Is there no way to get a new circuit board without buying a whole new key? I took my key apart the other night after reading some other posts where the poster had said the soldering came loose -- but in my case I don't see this, or at least if it is it's under the battery where it attaches to the circuit board or otherwise where I can't see it.

So back to Loren's point: So I am clear, Loren, are you saying that if I buy this new key from Sunset (not the housing like the Design Key but an actual new key itself that comes with the circuit board according to the parts guy at Suncoast) then I can just use my current transponder pill with it and I won't need to pay any labor or find someone with a PIWIS to do the programming?

If any of that is not true and it's possible to just get the circuit board/buttons seperately (without a new key) please let me know.

Thank you for the responses.

Edited by ferrugia
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Thanks for the response, Loren, but this DIY talks about taking out the circuit board from the old key housing and placing it in the new Design Key. The assumption I'm working under is that there's a problem with the circuit board so while the Design Key looks a lot better, it doesn't appear that it's going to solve the problem I'm posting about.

Thanks for the input. If anyone else has any other suggestions please let me know. Otherwise I guess the next step is to buy the new key head from Suncoast which is supposed to come with new electronic internals (including circuit board, etc).

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The only thing about this that makes me think it might not be the key is that I've noticed the following pattern: The remote lock/unlock never works when the car has been sitting for a long period, like when I've been at work all day and come out to drive home. However, if I then open the door manually, put the key in the ignition and turn the first click, then take the key back out again....the remote lock/unlock starts working again! Strangest thing. It's like somehow this wakes up the remote's sending or receiving signal and makes it work again. I've seen this numerous times and it looks like a consistent pattern of behavior.

I read in some other posts is that the car's computer will automatically turn off the remote feature to save battery....but after something like 5 days. Is it possible that mine is prematurely activating this functionality? Would there be a way to test with my Durametric if I leave it hooked up? I wonder if this is one of the many things a Duramteric can monitor -- I may call them tomorrow to ask that as well.

If anyone finds a solution in the meantime, please speak up. Thanks!

Edited by ferrugia
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One thing I have also wondered about is I have one key with a full key head remote w/transponder pill and another that is just only a key...no key head and no transponder pill. The second key is just the blade and small gray piece of plastic solid key head (so small it is very unlikely to contain a pill). They both work to lock/unlock (manually), arm/disarm the alarm and start the car. I've used both and there is no difference that I have ever noticed. Why is this?

I looked at those key heads w/circuit board from Suncoast and for $129.95 I'm considering getting one to fix my remote. Thanks for the suggestions.

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DBJoe - If you buy one and it works let us know. If you mention Renntech you should get dealer pricing from Suncoast and the price is $107.51 + shipping (~$6-8 USPS Priority) per what they quoted me yesterday. Good luck!

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Had to bump the fall season oil change/filter up the list with the wife :) (one beer job) and I have a very tiny leak of coolant from the AOS regions <_< (maybe a 3 beer job)...so those will have to come first, but I'm putting this on the list for the very near future because I think it would be cool to have it working again. I will certainly post the results.

Cheers :cheers:

Oh, and anyway, will be at the Daytona Beach Speedway Track for the PCA/Porsche Club Daytona Oktoberfest all Porsche all weekend racing event with my wife, chairs and cooler, so even the oil/filter change will be a bit postponed. Went there today during lunch and there are lots of cool cars in the garage area and activities already going...can't wait! I was so proud of my car.....and my wife...she just loves these events as well.

Edited by DBJoe996
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Problem solved. New CR2032 battery in the key head did the trick. I ordered another CR2032 battery to see if that fixes my second/backup key (which has never worked since I bought the car but I really haven't messed with that one too much) -- but the primary key is really the one I'm concerned with. My second key is actually a full key head, not the key blade only as DBJoe mentioned he has.

I'm surprised this was "only the battery" given the pattern I saw; specifically that it would start working after I would manually unlock the vehicle (implying it was potentially something related to the vehicle not just the remote in the key head). But I've learned that electrical issues and related observed behavior can be very strange and are often much more difficult to troubleshoot than mechanical issues. In this case it was an easy fix, so I'm not complaining. Having the alarm go off half the time I would unlock the car manually with the key blade was not cool.

Thanks to everyone for your input. Hope you have a similar experience as I did after replacing the battery. Maybe I'll get the Design Key in the future, it's definitely a lot cooler, but at the moment I'm going to hold off on spending $112.95 + shipping for a little plastic housing.

Edited by ferrugia
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One last point on this that's tangential is that I've noticed after replacing the key remote's 3v CR2032 battery, the distance from the vehicle that the remote consistently works is significantly better. I had been considering the A-pillar hack some time ago because I had to be literally right next to the vehicle for the remote to work. However after replacing the battery I'm not even considering it as the remote's working ~ 20+ ft away from the vehicle consistently.

The battery brand I pulled out of the remote to replace was a Renata. This is a Swiss-based company so I'm guessing this was probably the OEM battery that's now 10+ yrs old (the car's a 2002). Makes sense that it would need to be replaced and might only intermittently be putting out 3v after 10+ yrs of use.

Hope this information can help someone else in the future.

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Ordered another CR2032 (Panasonic ... $.99 w/ free shipping on eBay). Popped it into my second/backup key and now it works like a charm too. It was also a Renata as I mentioned in my last post, so I'm almost certain now that these were both OEM batteries that were 10+ yrs old. No idea why the guy who owned the car before me didn't just replace the battery as the second key was dead when I got the car (but it has considerable wear on the buttons so I know it was used a lot) but, whatever, $1.98 to fix both keys.

I think the take-away here is always replace the remote key battery first. It's a little deceiving that the little red light on the remote key continues to flash even when the battery has insufficient charge (as was the case with both of my keys).

Case closed. Cheers!

Edited by ferrugia
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  • 3 weeks later...

I had the same issue on my daughter's 1999 996. The drivers side door would open only intermittently when the button is pushed. She said both keys did the same thing. She replaced the battery in both keys. Based on this and reading through the threads here I decided it must be the motor inside the door or the car CPU. I also noticed that the pass. side door did not unlock. I also found that it would work every time by pressing the key button hard and in a certain area. After looking at the DIY, in this thread, I decided it must be the key circuit board. After taking the circuit board out, I found that the rubber tip on the micro switch was gummy and partly deteriorated. This explained why the button required a hard push. It was easy to see what happened. The back of the button has a small star shape that pushes on the switch rubber tip and the two are not exactly in line. Over time this just acted to destroy the rubber. As a solution; to make up the difference between the button surface and the switch rubber surface I decided to place a thin plastic shim (approx. 0.016") in the area between the two. This also serves to distribute the force on the switch. The switch now works every time with a normal push force on the button. I would have not found this without the great information in the forum. PS I have not looked at her second key yet but expect to find the same issue.

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Anyone have the electronic "guts" from a key that they don't need anymore? I wanted to experiment with swapping internal components to see if I could revive my key fob. Please shoot me a PM.

Maybe fix yours with parts from mine? Willing to mail back to find out!

Edited by 987_RDC
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  • 2 months later...

FYI - Well the battery that I installed literally 3 months ago today, to the day, has stopped working. Put a new battery in the FOB to verify and, sure enough, the new battery made it start working again..and from long range again (it had decreased recently).

My remote entry key is either eating batteries every 3 months now or this $.99 "Panasonic" battery off eBay is garbage... I'm going to guess the later and try a different battery that hopefully will last longer.

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  • 3 weeks later...
  • Solution

To finally close the loop on this debacle, the solution was to buy a new keyhead from Sunset ($125 + $6 shipping) and have my local dealer program the car with it (1/2 hr labor = $75).

If you read my troubles in this thread you will see this issue exhibited some strange behavior that made troubleshooting somewhat difficult to isolate: the issues were intermittent, a new battery fixed the problem for about 3 months but then it stopped working again, etc. My best guess about the original key remote is that it either stopped transmitting the correct frequency to the car 100% of the time as the hardware aged, or else it somehow became "out of sync" with the vehicle -- but I will never know about the later as the original owner did not provide me with the key codes when I bought the car so there was no way to try to "resync" using the code.

Either way, a new key head/remote did the trick for $200. Not bad. So in the future if you're having these problems then replace the battery first, and if the problems persist then just buy a new key head (996 637 244 42).

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  • 1 year later...

I have been having a problem with my remote locking on my 2000 Carrera 4 for a few months and it has been getting steadily worse, more and more unreliable. I bought new batteries for both remotes and it seemed better for a while then started playing up again. I checked out the internet for a possible solution and came across this thread.

The led was lighting up when I pressed the button but nothing unlocking or locking.

I took the keys apart and pressed the button on the circuit board, it worked fine on both keys.

So problem solved, I just put the key back together with a small piece of cardboard between the battery and the key back, this stops any movement of the circuit board and everything works fine.


This should save on expensive new keys.


Hope this helps a few people.

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