Swapping ECM

What issues should I expect if I put a used ECU in my 2002 C2cab? For instance, key programming, compatibility with other electronics, etc.

None of those when done the only way it really can be done (any other way and it won't work). Assuming the replacement DME matches the one required for your model year car, and has been programmed properly. If the replacement DME wasn't programmed with the right immobilizer codes the car wouldn't start, but your keys would still work. In any case that is a silly statement, because to program a DME to work with your car it has to have the same immo code to match what is already in your car. Only a dealer or shop with PIWIS subscription can access the IPASS codes, and to program a used DME the programmer (PST2 or PIWIS) must have the DME and Immo programming codes for both the used DME/immo and your cars existing DME/immo. About the only off chance for compatibility issues would be if you source a ROW (outside US) DME and the country code is not programmed to USA.

Thanks logray. Sounds like I need to do some additional research. I was under the impression that all the info was held in the ECU. Can you point me someplace to read up on the DME, the immobilizer, their function? Does the new ECU have to to be a matched pair to the DME, or can they be programmed to match? Thanks for your patience...this is my first Porsche.

Sign up as a contributing member on renntech.org and you can see this PDF which will tell you more about the DME than you need to know. http://www.renntech.org/forums/files...nt-systemspdf/ If you get your hands on the 996 work shop manual, it also has basic information about the different car management systems. The ECU (called DME in the Porsche world) controls primarily the engine, and in order to operate the vehicle it must be programmed with the immobilzer code "password" (otherwise it will not start). Likewise, the Immobilzier ("alarm/key" module) must have the DME's code "password" in order to work. The modules can be from any car, as long as the versions match which is typically model year range dependent, but the codes must also match for the car to work. Other notable modules on the car are airbag, instrument cluster, radio, etc., etc. etc. Why do you need to replace the ECU may I ask? Also, a rule here is good info like this should only come after posting some pics, and I see this is your second post... so where are the pics?

I know I'm having some trouble loading the pic. When I try to load it from my CP, it only shows option 1 which is to load it from a website. The option to load it from the computer is greed out. I'll figure it out though. I will take your advise and join with a membership. Thanks again.