Computer under driver's seat - 986 Forum - The Community for Porsche Boxster & Cayman Owners

roland3337 · 07-12-2014, 05:12 PM

I have a 2002 Boxster, non-S, 61k miles. Some days ago, I had some strange electrical problems. At first, I thought it was the ignition switch. But when I noticed water on the driver's side floor, and investigated related posts about bizarre electrical issues, I fear the computer under the driver's seat (that evidently prevents theft), got wet due to a clogged drain. The electrical problems are as follows:

Windows won't go down.
Won't start/turn over when the key is turned. (Dash lights and instruments come on, but nothing else happens. No clicking sound).
Front trunk won't open when the button is pushed (rear trunk will open, and right now, it does so when the key is turned in the ignition when I try to start it.)
Horn honks twice every 30 seconds or so.

My plan is to take out the driver's seat, dry everything out and say a few prayers that I the computer isn't dead. My questions:

Since the front trunk won't open, I can't disconnect the battery without getting access the hard way: cable near the right or left headlight from inside the wheel well. Can I simply do this without the key in the ignition, or should I take the trouble to disconnect the battery?
What is the exact name of this particular unit, in the event I have to find a replacement?

Thanks in advance, as always.

Roland3337

Paul · 07-12-2014, 05:16 PM

It's the immobilizer, and I would take the time to get the front hood open to disconnect the battery.

Also stop energizing it since it may cause more damage each time you try.

thom4782 · 07-12-2014, 05:33 PM

If you can't fix it, give these guys a call...Specialized ECU Repair, Replacement, & Testing - Restore or Exchange your Electronic Control Unit (ECU). Others have said good things about them. Cost to repair the Immobilizer is about 1/3 the price of the part new.

thstone · 07-12-2014, 07:42 PM

Roland, just so you know, the immobilizer (also called the Central Locking Unit or CLU) is coded to match the transmitter in the key fob and the ECU in the rear trunk. All three must have the same code or the car won't start.

Unfortunately, only a dealer (and a few rare indy repair shops) have the Porsche test equipment to re-program any of these components (key fob, CLU, or ECU).

You can buy a replacement CLU on eBay but you'll probably have to get the car (and new CLU) to the dealer so it can be re-programmed to match your existing key fob and ECU.

Paul · 07-13-2014, 05:17 AM

And you must have the learning code (password) for the replacement immobilizer. Dealers can look it up using the VIN of the donor car.

roland3337 · 07-13-2014, 05:47 AM

I'd heard about the need to reprogram everything at a dealer. Any guesses about how much $$$ this is going to cost me?

Paul · 07-13-2014, 06:11 AM

Worse case you will need new key remotes, a CLU, and programming. If the dealer can read your existing CLU's key codes, key remotes will not be needed.

roland3337 · 07-13-2014, 11:56 AM

I managed to get the seat out, along with the immobilizer. Really wasn't that difficult with the right tools.Unfortunately, the immobilizer itself looks toasted. The circuit board near the black 12 pin socket was charred and the copper foil bubbling up. I will need to send it in to Specialized ECU Repair. They will also need the ECU itself, which I think is in the rear trunk. But since I have the immobilizer out, I need to find a way to manually pop that rear trunk so I can get at it. That will be quite a trick without any power.

thom4782 · 07-13-2014, 12:24 PM

There is an emergency release cable for the rear trunk. It located in the rear driver-side wheel well. If you search the forum, you'll likely find a DIY on it.

Miata2Boxster · 07-13-2014, 12:54 PM

Quote:

Originally Posted by Paul

Worse case you will need new key remotes, a CLU, and programming. If the dealer can read your existing CLU's key codes, key remotes will not be needed.

This is the scenario I am looking at now. What is the approximate cost of the above from the dealership including new remote keys...mine are shot.? thanks

Paul · 07-13-2014, 02:16 PM

Your keys are fine, the issue is the only source for their passwords is your immobilizer. Hopefully it is in good enough shape that they can be downloaded to a PST-2. If you were closer I could do this for you.

roland3337 · 07-16-2014, 02:39 PM

Thanks, guys. I managed to get the immobilizer out, and I also managed to the trunk and extract the ECU, though my electric trunk release wasn't working. Because of some clear directions about removing the rear bumper, etc., I've got everything that I need to send off the electronic components for repair, so I can get my old friend on the road again inside a week, at a reasonable cost. You guys saved me probably $2000-2500.