computer going crazy

[Bill083]

I've owned my stock 2005 boxster for a few months with perfect reliability, until now. I had to (painfully) leave it out in the rain today at work. When I came out, my windows were half way down and the spoiler was up. I did not leave it this way. It started fine, but the "rear lid open" indicator on the tach computer screen was on. The lid was closed but the light stayed on. The spoiler would not go down. I also was unable to put the windows up until I drove for a few miles, then they worked. I brought it home and left it in the garage. My neighbor called to let me know the alarm was going off. I shut if off. A few minutes later, it alarmed again. I shut it down and started it up to recharge the battery and the computer indicated that the psm malfunctioned. The battery is now disconnected since it keeps alarming.

I'm fairly mechanically savy, but electrcal issues are beyond me.

Any suggestions? Please help.

[1schoir]

I've owned my stock 2005 boxster for a few months with perfect reliability, until now. I had to (painfully) leave it out in the rain today at work. When I came out, my windows were half way down and the spoiler was up. I did not leave it this way. It started fine, but the "rear lid open" indicator on the tach computer screen was on. The lid was closed but the light stayed on. The spoiler would not go down. I also was unable to put the windows up until I drove for a few miles, then they worked. I brought it home and left it in the garage. My neighbor called to let me know the alarm was going off. I shut if off. A few minutes later, it alarmed again. I shut it down and started it up to recharge the battery and the computer indicated that the psm malfunctioned. The battery is now disconnected since it keeps alarming.

I'm fairly mechanically savy, but electrcal issues are beyond me.

Any suggestions? Please help.

Check to see whether there is any moisture or water under the driver's seat or in the foam padding under the carpet behind the seat. The symptoms you describe sound like your immobiliser may have gotten wet. In some instances, you can take it apart and clean it/dry it with isypropyl alcohol and revive it without any further problems if you get to it soon enough.

If there is water intrusion, make sure that you clean out your drains to prevent a repeat occurrence.

Regards, Maurice.

[Bill083]

Thaks for the fast reply. I'll check it out.

[Bill083]

Right you are Maurice, it's saturated down there.

Edited May 5, 2011 by Bill083

[1schoir]

Right you are Maurice, it's saturated down there. I hate to bother you, but is there a good source of how-to information on removing my seat and cleaning the drains?

No bother...we are all here to share information. BTW, , sorry it had to be under such circumstances.

You can easily remove the seat with a female torx socket by unscrewing the four bolts that hold the seat rails in place. To access the two in the rear, slide the seat all the way forward, to access the two in the front, slide the seat all the way back. If you don't have a torx socket, in a pinch you can remove those four bolts with a 1/4" drive 10mm good quality socket. 1/4" drive will give you a decent enough fit to get the job done. There is also a large connector under the seat, but if you disconnect that one, make sure that the ignition is off AND that the key is out of the ignition, otherwise you will set off your airbag light, which can then only be turned off with a PIWIS, PST2 or Durametric.

Note that (at least on 986's) the cable under the seat is long enough to allow you to pull the seat out and lay it directly next to the door sill, outside the car, possibly elevated on a suitable box or platform. That avoids the difficulty in undoing that large connector, which is a little tricky if you've never done it before and avoids the airbag light problem.

For the drains, go to this link for photos and DIY instructions: http://sites.google.com/site/mikefocke2/drainsdiagram

Don't put off taking the immobiliser apart and at least drying it out, maybe with some warm air from a hair dryer set on medium. The fact that your Boxster started probably means it hasn't gotten fried, so be pro-active and it might turn into a non-event. Do a search here as I believe some have cleaned the circuit board with isopropyl alcohol or another similar circuit board-friendly solvent.

After you are done, you should be able to discern whether "it's all good" if all of your symptoms have disappeared.

Be absolutely sure to find out if it's only a matter of clogged drains, as opposed to torn or ripped foam drain trays which sometimes get damaged by a dangling pushrod after one of the plastic ball cups on the end of the pushrod breaks apart or pops off. We can work on that after you take care of the more pressing issue of rescuing the immobilizer.

Regards, Maurice.

[Bill083]

I removed the seat and was able to lay it alongside the car without disconnecting the large connector as you stated is doable in the 986. I was not able to get to checking the drains yet, but will do so once I get the other issues sorted out. It's in a carport so that can wait.

I removed the circuit board and inspected it. There was a fair amount of corrosion on the one end. I very gently cleaned it with the ipa and a soft brush as u suggested. I reinstalled it and all messages seemed to go away except the "psm failure". I don't feel comfortable using the car with any messages showing since that indicated to me that the board overall isn't trustworthy. I gave it a much more vigorous cleaning since I feel I've got nothing to lose at this point. If it does not work 100% tomorrow, I'll have to replace it.

Two questions;

1) Where do you suggest I purchase the new board, and what should I expect it to cost?

(I am unable to find this part anywhere on the net. I've just contacted the local dealer with a part inquiry but would really prefer to find a reputable online parts house.)

2) I've read somewhere on the net of people drilling a small hole and inserting a rubber grommet in the floor near the immobiliser to let water drain out if this should happen again. (I will be diligent about the drains from now on, but I'm paranoid and would like some extra insurance.) I can not see what is below the floor. How safe/dangerous would it be to attempt this? I have no idea what is below the floor here, electrical, brake or fuel lines, etc.

Edited May 6, 2011 by Bill083

[1schoir]

I removed the seat and was able to lay it alongside the car without disconnecting the large connector as you stated is doable in the 986. I was not able to get to checking the drains yet, but will do so once I get the other issues sorted out. It's in a carport so that can wait.

I removed the circuit board and inspected it. There was a fair amount of corrosion on the one end. I very gently cleaned it with the ipa and a soft brush as u suggested. I reinstalled it and all messages seemed to go away except the "psm failure". I don't feel comfortable using the car with any messages showing since that indicated to me that the board overall isn't trustworthy. I gave it a much more vigorous cleaning since I feel I've got nothing to lose at this point. If it does not work 100% tomorrow, I'll have to replace it.

Two questions;

1) Where do you suggest I purchase the new board, and what should I expect it to cost?

(I am unable to find this part anywhere on the net. I've just contacted the local dealer with a part inquiry but would really prefer to find a reputable online parts house.)

2) I've read somewhere on the net of people drilling a small hole and inserting a rubber grommet in the floor near the immobiliser to let water drain out if this should happen again. (I will be diligent about the drains from now on, but I'm paranoid and would like some extra insurance.) I can not see what is below the floor. How safe/dangerous would it be to attempt this? I have no idea what is below the floor here, electrical, brake or fuel lines, etc.

Bill:

Glad to see you are making progress.

Before going the replacement route, I would first attempt to "reset" the PSM failure message and see if it comes back. Someone else can chime in here whether it's possible to do that just by disconnecting the battery for a few minutes or whether a PIWIS or Durametric are the only tools that will reset that message. It's certainly within the realm of possibility (probable, even) that there is no PSM failure, just the indication and that it has to be reset.

As for replacement, the part is the complete immobilizer, and it has to be programmed with a PIWIS by using the IPAS codes (that you can get from the dealer) because the keys must be reprogrammed, or more accurately, the immobilizer must be reprogrammed to the keys IIRC. I know that you only get one shot at programming an immobilizer, so that is probably best left to a dealer or a competent Porsche indie. A good online dealer is board sponsor Sunset (Porsche Parts at dealer cost tab near the top right of every page). Suncoastparts.com also has good prices and service. Either one is much better than your local dealer is likely to be.

One of the places that you have to be very careful is along both sides of the car, just inboard of the rocker panels/door sills, as the brake lines, power steering line and clutch line run along the left side and the a/c lines fuel lines run along the right side. Under the center longitudinal line run the radiator hoses and there are two lines that run from under the left rocker panel towards the center not far from the middle of the car's underbody. Nonetheless, don't drill anything without having a look underneath for yourself and, if you are going to go that route, be sure to rust-proof the circumference of the newly-drilled hole.

Here are a couple of photos of the underbody so that you can orient yourself:

Looking forward from driver's side rear

Looking forward from driver's side rear

Looking forward from passenger's side rear

Also, note that these are from a 986, but I believe the 987 is similar.

Regards, Maurice.

Edited May 6, 2011 by 1schoir

[Bill083]

Maurice,

You've been an amazing amount of help to me with this issue. The underside views were very helpful.

I managed to borrow a floor jack and lift the driver's side of the car. Upon removal of the underpanel, I was able to easily drill two 3/8" holes in the low spots of the floor without risk of puncturing anything important. I siliconed in two grommets to protect and waterproof the holes, and put some mesh over the top to prevent the foam from forming a seal on the grommets. Now if any water does leak in, it will hopefully be able to drain out.

I found a small amount of debris in both side drains under the roof. It didn't seem to be enough to cause the problems, but I blew and flushed them out. I flooded both sides with a garden hose and detected no water intrusion.

I reinstalled the immobiliser and everything worked fine, but the "psm error" was still present. I took it out for a drive and after just a mile or two, that error went out.

I really thought I was headed towards a $1k stop at the porsche dealer. You've saved me a bunch of cash and tought me some things about my new love along the way.

Thanks again,

Bill

[1schoir]

Maurice,

You've been an amazing amount of help to me with this issue. The underside views were very helpful.

I managed to borrow a floor jack and lift the driver's side of the car. Upon removal of the underpanel, I was able to easily drill two 3/8" holes in the low spots of the floor without risk of puncturing anything important. I siliconed in two grommets to protect and waterproof the holes, and put some mesh over the top to prevent the foam from forming a seal on the grommets. Now if any water does leak in, it will hopefully be able to drain out.

I found a small amount of debris in both side drains under the roof. It didn't seem to be enough to cause the problems, but I blew and flushed them out. I flooded both sides with a garden hose and detected no water intrusion.

I reinstalled the immobiliser and everything worked fine, but the "psm error" was still present. I took it out for a drive and after just a mile or two, that error went out.

I really thought I was headed towards a $1k stop at the porsche dealer. You've saved me a bunch of cash and tought me some things about my new love along the way.

Thanks again,

Bill

Bill:

Thanks for the kudos.

Pat yourself on the back for your perseverance! Your solution should provide you with additional peace of mind.

Take some of the $$ you saved and buy some goodies for your Boxster!

Regards, Maurice.

[Howard Lew]

If I havn't driven by 06 987/S for a month or so, I do keep it on a trickle charger, Porsche's, the right one...for the first few blocks of driving or so the PSM light goes and stays on as well as the ABS brake failure light....after driving a few blocks around my neighborhood, they go out, then I'll drive it for half an hour or so....I should drive it weekly.....some weeks twice....whenever i do drive it, I want to make it my daily driver....

[Bill083]

Well after a year of successfully using my dried out computer, I guess the corrosion finally made it's way through something important. A few weeks ago I tried to put the top down and ....nothing. No clicks or pops, just nothing. I took it to my local porsche guy, Mike, and he gave it a good thorough going over and everything checked out except he couldn't communicate with the computer. I had to take it to the local official porsche dealer and they found that the rear control module had failed. They replaced the module ( I assume it's the same one under the seat that got wet a year earlier, but the tech that fixed it was not available to ask ). As to the cost, $350.81 for the part, $330.20 labor, G.O.G. & supplies ( no clue wtf that is) $20.00.

Lesson learned; not keeping drain holes clear=$743.07.

[wvicary]

We clean the drains on all vehicles as normal maintenance.