996 911 2004 CARRERA 4S - CAR NOT RESPONDING TO KEY FOB

[MARKTHESPOT]

Hello All, 

 

My car is not responding to my key fob - when I press the unlock and lock button on the fob, it blinks red but the car does not receive the signal. When I went to go program my car at a local shop, the mechanic stated it might be a door actuator and that there might be an issue with my central alarm locking system. Has anyone else experienced this problem? If so, please let me know what the culprit is and what I should focus on fixing in order to resolve this problem? 

 

Thank you all! 

[judgejon]

Change battery in key fob.  Might be an issue, cheap enough to try. 

[MARKTHESPOT]

Hey judgejon, 

I changed the battery in the key fob and that did not fix the problem. Any other suggestions? 

[judgejon]

You might need help from the stealership on this one.  Might take a piwis to reprogram everything.  Best I can say. 
Others here will likely jump in. 
Good luck. 

[DBJoe996]

Your 20 year old key fob has stopped working.  Welcome to the club.  Your circuit board in the key has broken and now doesn't work to lock/unlock the car.  Mine has been that way for 15 years.  I just use the blade to lock/unlock.  Options?  Go to dealership, order new keys from Stuttgart (only place in the world to get replacement keys), put wallet on counter and empty it of all remaining credit cards (read this as replacement keys are very expensive - $450 plus each plus ensuring programming  correctly to your car - Porsche dealer only).

[judgejon]

Mark, there you go...one of the pros has stepped up to the plate.  As suspected, your next stop to fix this issue is your local friendly stealership. 
Again, good luck. 

[JFP in PA]

Considering what people do to these key fobs (gone through the family washer, spent a couple of days at the bottom of a lake, ran it over with the car, etc.), I am surprise that they work at all.  Eventually everything wears out; when it does, then it is time to go to the dealer and make your wallet a little easier to sit on.................😉

[987_RDC]

For fixing just the remote FOB: Makes me wonder if you could take one of the important chips holding the immobilizer coding and re-solder it to another used eBay key.

 

The bummer about the 996 keys is to reporgram with PIWIS you need the unique key tag (comes attached to new key) and the iPAS codes for the car. (done this w my PIWIS)

You can re-code a used ebay 987 key on 997/987 cars. (not personally done)

Edited April 29, 2021 by 987_RDC

[JFP in PA]

Problem is that the information is in what is called an RFID "pill", which cannot be altered without killing the coding, which is why the dealer network makes a killing selling replacements.  You can try moving the pill, but you could end up right back where you started 😱

[987_RDC]

Actually there are a few pieces of the key (which you know). The mechanical blade, immobilizer pill & Fob electronics(w coding to immobilizer). A mechanically cut key will unlock the door. A mechanical key + pill will start the car. The fob is just for the remote unlock of the doors & disable of alarm.

So Mark (and myself with a dead key electronics but with cut key and pill) will mechanically open the door and if fast enough turn the ignition to Run before the alarm goes off. If you wait too long then you get the embarrassing honking.

You can move the pill and mechanical blade to another plastic housing and leave out the now "dead" electronic fob.

 

Regarding reviving the FOB:

What would be great would be to figure out what chip is out of spec. Best case would be a capacitor or resistor. If it is a worn trace then that could technically be repaired. If the actual important chip of the immobilizer coding has "worn out" then Fob is done for.

 

Back when I had a 02 NA 996 I never did figure out how to revive my fob electronics. I ended up getting a 2nd key NEW (very important) and then was able to have two working keys for driving the car but only one working fob for remote lock/unlock.

Edited April 29, 2021 by 987_RDC

[987_RDC]

1 hour ago, JFP in PA said:

Problem is that the information is in what is called an RFID "pill", which cannot be altered without killing the coding, which is why the dealer network makes a killing selling replacements.  You can try moving the pill, but you could end up right back where you started 😱

I think what you are referencing is the risk you can run later when you find an old key you lost. Unless you have all your keys and then also the new key (w unique coding tag) when using the PIWIS that is all that gets put back into the immobilizer. That happened to someone I know. Had two keys and lost one. Went to dealership to add a replacement and left with two working keys. Found original lost key but now that key is useless, only can open the door but cannot start car nor remote lock/unlock.

 

The issue above could of technically be resolved if when new from Porsche both the keys from the factory had their unique code (key white tag code) included on some card. Even better would of been to store that info somewhere in the DME from the factory.

Edited April 29, 2021 by 987_RDC

[JFP in PA]

Here is where that falls apart:  The code on the white tag is fed to the PIWIS system, which runs it through some sort of "protected" algorithm to generate another code sequence that is then fed to the central locking computer under the seat, where it is stored in an encrypted form.  The DME stores nothing.  When you put a working key into the ignition, the central locking computer sends a "go/no go" signal to the DME to start the car, if the information from the pill in the key corresponds to the encrypted code sequence in the central locking unit, the correct start signal is sent to start the car.  So the DME has nothing stored in it, and the central locking computer as an encrypted code sequence that triggers the system to function, only if the pill matches what it expects to see.  So even having the original white tag gets you nowhere with out the PIWIS to generate the second code sequence and then encrypt it to a form the central locking computer accepts. One or two firms have figured out how to lift the encrypted data off the central locking unit and transfer it to another, but that only works with the original keys; and to my knowledge no one outside of Porsche has figured out how to get the code for a new key stored in the central locking system without the PIWIS.

 

You have to remember that the reason for the key pill system is to keep people from stealing the cars, so they didn't make it either easy or cheap to replicate the key. 😉

[987_RDC]

Oh I meant just the 24 digit fob codes from the original keys should of been saved somewhere. Last time I was poking around I think I uploaded my radio code into a writable area of the DME. I think with white tag codes that you could at least redo the PIWIS process with one original key + 2nd new key + 2nd original lost key and then end up with three working keys.

 

It just kind of sucks to have an original key that no longer functions. Unless you know of a way to find/recover the 24 digit codes from original keys. Did Porsche save this info somewhere matched to the VIN?

Edited April 29, 2021 by 987_RDC

[JFP in PA]

2 minutes ago, 987_RDC said:

Oh I meant just the 24 digit fob codes from the original keys should of been saved somewhere. Last time I was poking around I think I uploaded my radio code into a writable area. I think with that you could at least redo the process with one original key + 2nd new key and then end up with three working keys.

 

It just kind of sucks to have an original key that no longer functions.

 

One big problem with that, is if you purchased the car new, you probably didn't get the code tags as most dealers throw them away. So by the time the vehicle is in the hands of a second or third owner, you are "SOL" as the expression goes. 😐  We have even more than once had a single owner lose them after having to get new keys or having to preplace the central locking computer because water got under the seat and killed it.

[987_RDC]

Sounds like you already solved the issue. Dealers had the white tags and did not keep them with the car.

 

Too bad they did not come on a card that was placed in the user manual as the guy who has the "bad original 2nd key" is the original owner.

 

Just looked up new fob heads and seems they are not as bad as I recall. Like $170

Edited April 29, 2021 by 987_RDC

[JFP in PA]

No, just an astute observer of human nature and the tendency of people to dispose of things people think unimportant.  If you just look at the number of radio code request on this website, you will quickly understand that a simple four digit code, which comes with the car on a plastic card that tells you what it is and why you should safely store it, and is often written in the owners manual by the dealers as well is nowhere to be found by the original owner five years down the road when the battery needs to be replaced.  If they cannot find that when it is required, the chance of unexplained small paper tags surviving is even more limited.  Short of requiring the owners to have the data tattooed on their foreheads, you have near zero probability of the tag's information surviving, and why shops that regularly service Porsches have a regulated power supply to maintain the radio code while swapping out batteries.........................😉

[987_RDC]

Always nice when you remove a radio and see that someone has "sharpied" the code onto the top.  I started doing that or coding into the DME.

[akk65]

Just got new fob and programming. There are max. four keys that car regonizes. If all key slots have been used, its possible overwrite one. A problem can be what old key overwrite, if you have no keys white code tags available. I took photo from white code tag and printed it to paper, and which goes to my porsche binder.