Immobilizer water damage - 986 Forum - The Community for Porsche Boxster & Cayman Owners

My car was left open to the elements during a severe storm and the immobilizer was damaged. I removed it and cleaned it with isopropyl alcohol and while it does behave differently, the windows will not go up or down using the switches, frunk and trunk not unlocking, nor will the car start.**** I was planning on reaching out to ECU doctors in Florida to see if they can repair or buy a used one and use one of the cloning services on ebay. Last option is to purchase a matching immobilizer, ECU, and Key FOB from ebay. From what I have been reading I do not need the tumbler as I can add the old key blade to the replacement FOB. Is there any other part that I need? Do I need the matching signal transducer (996.618.159.01)? I noticed some sellers including the ignition tumbler, Door tumbler, and the signal transducer. Others just the immobilizer, ECU, and key Fob. Does anyone know what else I should check for damage? There was water pooled in space below the seats. I have removed all carpet and dried it all out with fans, including the foam under the carpet which took days.

What year is your car?

It's been discussed a lot in the past - because it happens to someone's car regularly here. I have bought many various salvage Boxsters and have done the swap of a similar year and model Key fob, DME (ECU) and Immobilizer Box (Central Locking Unit). The signal transducer (996.618.159.01) is not needed. The drawback of doing it this way is that that car's specific info such as the VIN, detailed equipment, and engine history (over-revs) will not be in the parts that you swapped in. It will lead to problems if you have it serviced at a Porsche Dealership in the future. I'd recommend ECU Doctors for a reliable repair if you value the car enough for the expense. Otherwise having the clone done is a better option that swapping parts from another car. In my case, I recently bought a 2002 that hadn't run for over a year and the immobilizer board was beyond repair. To get it running and start evaluating the car, I swapped in the fob/Immo/ECU from a 2001. I'll decide if I want to get the original immobilizer cloned. The car needs a lot of maintenance - suspension, paint and minor body work and I have yet to decide if I want to put money into making everything right or just have it functional. Note: There are many versions of immobilizer box. If you buy one, make sure that it is the same part number as the original.

This is great info, thanks!

Disregard, the car is sorted. I thought I could just keep the old key close by but needed to swap the RFID pill between remotes. Car fired up and now just need to put it back together and sort some replacement seat covers for my 997 seats.

Purchased immobilizer from ebay and sent source and donor immobilizer to Velectronix and they cloned the immobilizer and shipped back to me the same day. Cost was only $250 and works perfect.

The 2002 Boxster that I mentioned earlier in this thread came with three keys, but a very bad immobilizer board. I decided to go ahead and fix it. I marked the chip that needs to be transferred and gave it to a friend that repairs biomedical equipment. (I can do surface mounted soldering, but I'm not a pro.) The board looked so bad that he told me he expected it was fried, but I said to go ahead. It took him less than ten minutes to remove the chip and put it on a good board (same version) that I've had in storage for a few years. It worked flawlessly and I now have three functional keys for the car. He was excited to hear that it worked out and he is willing to do the same for anyone else for a small fee.

Very interesting and extremely valuable information! How did you identify this chip? Edit: Conversely, this means that you should get yourself a suitable board so that you’re prepared just in case?!

The old one looks like it blew the fuse mount right off the board. Impressive. I assume the chip that got transferred holds the coding to the VIN/chassis.

There was some detailed discussion about the immobilizer years ago. Somewhere among posts from Nine8Six, Qmulus, and Particlewave I figured out which chip. You can find more info about it if you search or ask AI: "immobilizer 93LC56" The Modules used to be inexpensive and easy to find on eBay. Now they are selling for $750 to $900 USD. Yes, that chip has the info and it can either be read, then written to another chip or just removed and transferred to a new board.

Note: Another issue to watch out for when doing this repair is damage to the connector on the wiring harness. Power to the module can remain 'hot' to the module even with the key off and removed (the module controls the alarm system). Having that current run while the module is damp corrodes the connector.