Water under driver seat... What to expect?

[HammerESQ]

I went to start the box this morning, turned the key, and nothing, tried again... NOTHING. Then the alarm started going off!

Placing my hand under the driver seat revealed 3" of water, and the alarm module was totally under water. I removed the seat, disconnected the module and shop vaced out the water in my car.

I then took the computer inside, opened it up, dried it out, and that's pretty much where I am right now.

The remotes don't work to lock or unlock the doors, or the trunk. Both front and rear trunk release in the car appear to be stuck closed.

A couple of questions for those who have been here before:

* When the alarm computer finished drying out, and I put it back in the car my understanding is the car may be in a 'failsafe' mode where it is dead until a Porsche dealer hooks it up to their scan tool and resets something? Can anyone tell me more about this? How much does it cost?

* I suppose (looking at the pictures) there is a good chance my alarm module is toast, is there a way to diagnose this before going to the dealer?

* Is it possible to purchase a used alarm module from ebay or a junkyard and have it reprogrammed, or is this something that the dealer must buy new?

Thanks for the help!
-Eric

Pictures to follow:

[JackG]

There's very little reason that the module wouldn't be good once it has dried out. Most modern PC board manufacturing processes use water soluble flux solution, and the boards are cleaned (after the soldering process) in what is basically a dishwasher with water!

The thing is that the dirty water may leave deposits on the board which can interfere with it's operation. Also, you may have some components, such as relays, which may be difficult to get dried out completely.

If it were mine, I'd get some canned PC board cleaner and spray it down on both sides, then bake it in the oven at 100 - 125 degrees to get it completely dried out.

Hope that helps!

[skip_168]

Well, unfortunatly It looks like you allready have alot of corrosion on the top metal layer of your board..(it looks like green fuzz or powder on the exposed terminals..) this corrosion eats the top copper layer which is about .0014 inches thick, and eats away the FR4 & the prepreg in the laminate..


here is the kicker:

These boards are all low voltage operating systems, i.e. the boards run at 1.8,3.3, or at the most 5 volts, some of the relays run at 12V... this is well under the voltage neccary to use water as a conductor..(I think its around 20V or so.. salt water is less)... so this board apears to have been getting moisture in it for some time, and the corrosion just now interupted the logical signal path..

But hey, I always dry them out as a first attempt... my daughter runs her cell phone through the wash every month or so...

Dry it out as best you can, use some denatured alcohol as a solvent, & put it in the oven at a low temp.. 125deg F should be safe, but watch the plastic parts carfully.. if they start to deform then you are toast..(pardon the pun)..

I always use a vacuum chamber, but not everyone has access to an electronics lab... also, use some ESD(electrostatic Discharge) protection.. you could fry the board just by touching any of the exposed leads...

[CJ_Boxster]

Originally Posted by skip_168

Well, unfortunatly It looks like you allready have alot of corrosion on the top metal lay of your board..(it looks like green fuzz or powder on the exposed terminals..) this corrosion eats the top copper layer which is about .0014 inches thick, and eats away the FR4 & the prepreg in the laminate..


here is the kicker:

These boards are all low voltage operating systems, i.e. the boards run at 1.8,3.3, or at the most 5 volts, some of the relays run at 12V... this is well under the voltage neccary to use water as a conductor..(I think its around 20V or so.. salt water is less)... so this board apears to have been getting moisture in it for some time, and the corrosion just now interupted the logical signal path..

But hey, I always dry them out as a first attempt... my daughter runs her cell phone through the wash every month or so...

Dry it out as best you can, use some denatured alcohol as a solvent, & put it in the oven at a low temp.. 125deg F should be safe, but watch the plastic parts carfully.. if they start to deform then you are toast..(pardon the pun)..

I always use a vacuum chamber, but not everyone has access to an electronics lab... also, use some ESD(electrostatic Discharge) protection.. you could fry the board just by touching any of the exposed leads...

Do what is refered to by some as a Cool Down Bake, Let your oven heat up to about 125 degrees, then once your oven is up to that temp turn the oven off and quickly and safely place your wet item in the oven and leave it there till the oven is cooled down to the touch. That's the method the we use at the shop when we customize or refinish wheels and have to dry the paint on center-caps.

[abboxster]

Thanks all,

I'm in the same boat (bad pun).
Is it possible to remove the control unit without taking the seats entirely out?
Also, I dried the car out over night and managed to start the car the next day.
That evening I was stranded again and dried again overnight and started again
the next day a number of times. Today (day 3), once again I am stranded and I am considering taking out the control unit and drying it. Can I use electrical contact cleaner and a hairdryer to accomplish this?

[JackG]

Originally Posted by abboxster

Thanks all,
Can I use electrical contact cleaner and a hairdryer to accomplish this?

No. Most electrical contact cleaners have additives in them to inhibit corrosion and lubricate the contacts. This will not be good for the board, as it will leave a residue. You need a dedicated PC board cleaner, not electrical contact cleaner.

You'd be better of to simply dry it with the hairdryer, but even that's not a great idea. It'll take a lot of drying to get all the moisture out from under the components (where you can't even see it), and it'll be hard to get it hot enough, evenly enough.

Seriously, most solid state devices are rated for storage temps that go up to 125 degrees C, and operating temps to 85C. That's 257F and 185F. Automotive devices are rated even higher for their harsher environment.

If you do the CJ trick and heat your oven to 150F, then turn it off and place just the board in there and close it up until it's cooled back down, you should be miles ahead. After all, think about it... if you were parked in Phoenix in the summer with your windows up in the middle of the day, how hot would it be inside your car for those several hours? Yeah, over 125F, at least. It's built to take that.

[abboxster]

Oh My! Talk about corrosion. That board was completely corroded. I dried it and intalled and still no difference. The car does everything but start. Lights come on, top goes up and down, windows do the 1/2 " close when the door is opened and shut, the car does everything but start. Any suggestions?

Also, I was wondering if I maybe the key needed programming as all the other things work except for starting? If I replace the control module would I still need to have the dealer replace and program a new key head?