Thanks, fixed.

Let us know how it works out. $13.32 (shipped). Nice. Assuming it works, this would be a great inexpensive option to get the job done.

Just a heads up when you get to the EEPROM read step. I noticed after the fact that the EEPROM programmer software that I was using also had device listings for the Atmel version of this EEPROM. The Atmel device listings had separate x8 and x16 organization options. Had I found this beforehand I could have just selected the Atmel 93C86 (x8) for the read. Using this, I wouldn't have had to lift pin 6 during the read and the byte swap on the data would have been unnecessary. (Although the EEPROM in the Kessy is a Microchip part, the Atmel and Microchip parts are functionally compatible.) I know that a lot of these programmers are using the same software or clones, so you might run into this with the programmer you are using.

Used and that will work? No. Once a key has been programmed to a vehicle it cannot be repurposed to another vehicle without replacing the transponder chip. I do not have a confirmed good source for transponder chips but I know they are out there. To replace the transponder chip you will have to disassemble the key which means destroying the case (since it is glued together). From my experience, factory blades do not fit correctly on the replacement cases so you will have to get a new blade cut. If I had some good factory keys lying around and new transponder chips I might have gone this way, but it seems like a lot of work otherwise.

I did find a source for aftermarket entry and drive (aka keyless go, aka proximity) keys: https://www.uhs-hardware.com/product...s-go-rfk-por-b . I bought two of these. One works great. Unfortunately, the second one has problems. The entry function doesn't work at all and the key must be within six inches of the ignition to be detected. I'm working on getting the second key swapped out. I suppose my bad experiences with aftermarket keys would be one reason to attempt to repurpose a factory original key.

My understanding is that this is true for the 993 (and maybe early 996 vehicles?). For the Cayenne, the dealer lost the ability to give out these codes 15 years ago. Prior to this, the dealers got the codes directly from Porsche and the technicians would input the code during the key programming process. The system changed to where the codes are now concealed from the technician and the process goes through the web. The only way I know of to get the code from a dealer would be to intercept the communications between the vehicle and the PIWIS II/III and then extract the code from the appropriate message. This is a lot of trouble and would require a dealer visit, which pretty much negates the whole point. The process I described is the easiest and cheapest way that I know of to get the code.

 

Awesome post! Thanks a lot.

By any chance you know how to reset and re-program the entry-and-drive key for 2018+ model / Piwis3? Would the procedure be any different? Is the newer model also using the Kessy module?

 

Being several generations newer, a 2018 model is going to be totally different. I don't know if anyone outside Porsche has figured this one out but it's certainly possible they have. There are key reprogramming packages made by 3rd parties which are sold to locksmiths and independent shops. You could call around and ask someone who does this if they have have the ability to program keys for a 2018 Cayenne. Otherwise, it will have to be done by a Porsche dealer. A PIWIS 3 alone won't help because it needs to be logged in to Porsche's servers, and only a dealer will have this capability.