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987 Roof issue


New member
24 Mar 2021
Hi readers and experts.

Some help please.

I came out to my Boxster the other morning after it had been raining heavily to find the windows one third open and the rear spoiler raised.

In my ignorance, I assumed the hood had some sort of issue, so I unclipped and lowered it. Two loud cracks followed and the roof went limp (not a good sign).
I checked the hood actuator push rods to find the white plastic cups destroyed, even worse, when I had tried to raise the roof again, the sharp rod ends had punctured the membrane that keep water out of the cabin...

I disconnected the battery overnight, then reconnected next morning to see if I could reset whatever caused my issue with windows and spoiler, sadly, on closing the windows, they shut briefly for about 1 second before opening one third again, spoiler still would not go down.

Undeterred, I purchased and fitted a new pair of rods only to find they both sheared when I closed the roof, looks like they were not detecting the roof fully up, and kept going.

The battery then died, I charged it up, but it only seems to last a few hours before going flat (car just sitting in the garage), I assumed a duff battery, so purchased a replacement - same issue.
I also get a "Hood not fully up" and "Spoiler controller failure" messages on the dash.

Reading on this site, I see a couple of vaguely similar issues, so I removed the passenger seat and took a look at the rear control unit - a close inspection of the pcb looked fine, and no sign of water ingress, just a couple of dead flies..

Before I take it to the local OPC for diags, anything else I should check before my wallet gets a thumping??

Apologies for a long winded tail!

ANy hints would be gratefully received

Thanks, gmb
You need the help of the resident Guru, Mr deMort, we're lucky enough he graces us with his presence around 7-9pm most evenings.

Good luck, that all sounds pretty grim.
Interesting .. ok ..

Water ingress to the passenger seat area and damaging the rear control unit that's there .. this will cause ..

The roof to cycle until it breaks the roof push rods .. it will flatten the battery and it will raise the spoiler .. a flat battery does do that on its own though .

Put you hand down the back of the carpet between carpet and the rear bulkhead .. if wet then its probably water damage and a new rear end cu is required ..

If dry it can still be the rear end cu .. any water bottles under the seat .. apples .. bottles of milk ? yup i've seen it all .

As individual faults ..

A failed micro switch on the roof lock catch and the windows wont fully shut

A pressed key fob in your pocket will drop the windows .. there is a mod to stop this .

A battery discharge fault ( flat battery ) and the spoiler will raise ..

New rods broken and the coding in the rear cu is incorrect .. there is a new and old setting .. get it wrong and they will break .

Off hand though .. you have the classic symptoms of a wet rear control unit under the passengers seat .

A water bottle jammed there and a small leak will do the same as a rear drain flooding the car so dry doesn't always mean its ok .

By the way this is based on a 987 .. if you have a 986 its totally different .

Rear end CU replacement is circa £500 .
Wow, thanks deMort.
I did think of the water under the seat bit, but I removed the passenger seat and removed and inspected the cu, looked perfect, but indeed the battery did go flat a couple of times.
Guess the only option is the OPC, just hope my local one (only in business a couple of years) is up to and willing to look at a 16year old 987...
A local porsche specialist would be a bit better .. we are more versed on working on these cars than OPC these days .. basically most of us Indy guys are ex OPC and these are the cars we grew up with !

It could be a rear end cu that's at fault or it could be seperate faults .. pretty much into i would need to see the car to comment further im afraid .

Im sure the OPC will do just fine in diagnosing this .. OPC mechanics are not stupid .. just time rushed i'm afraid .
Many thanks for the advice Mr deMort Sir.

Here in Perth Scotland, we are a bit light on indy specialists - unless you know of any way up here in the frozen North...

- gmb
Wee update, Perth OPC have had the car for over one week, so far they have adjusted the hood so it does not break the plastic rod ends (even though I asked them to just change the RCU, but they are the specialists).

They seem to be confused as its showing various voltage faults on their diags.

I've asked them to please just change the RCU anyway as the spoiler and roof faults both point at the common failing unit (IMHO), so they are ordering one now, unfortunately, they say as its coded to the car I have to pay for it even though it may not fix the issue, I guess I've no choice there as they wont budge on that.
If that does not fix it they advise they just give me the car back, as they are out of ideas / too expensive for them to spend any more time on.
Bill so far > £1200....
Sometimes i have to admit i sit here banging my head against the desk in frustration ..

To replace the rear end CU is in the region of £500 .. ok maybe more as OPC labour rates are just stupid these days but to not be able to diagnose what i consider to be a simple fault .. to actually tell you to go away with the fault ..

It beggars belief ..

We have a spare one in the draw we can fit and prove this ...OPC have them in stock .. they can easily do the same ... i don't need to but it's a total way of proving an issue .. this type of fault is common .

yes its coded to the car .. it actually comes with basic coding already .. i can fit a second hand one to any car i choose .. i just alter the coding for that car .. ie some have new and old arms .. we code it accordingly ... it's NOT stuck to your car forever .. sigh .

Voltage issues .. this could be a faulty Rear end CU .. it could be a supply or earth issue to the control unit .. i can't say from here .. bloody wish i could though ... not hard to use a voltmeter and check the control unit feeds and earths .

My best guess is a rear cu that's at fault from the description of the faults but i would need to see the car to confirm ..

if they cant fix it complain to Porsche customer support .. if they can then complain to Porsche customer support ..

You shouldn't have to pay for people that dont know what they are doing .. take it away broken .. Stuff me is all i can say without being seriously rude .

i feel at this point it would have been cheaper to ship the car to me .. £300 at a guess .. i fix it and return it .. ..

Think i need to go cool off .. im madder than you are !
Well, another 3 days to fix the RCM, but wooo hoooo, its fixed (or so they tell me), just away to pick up the car now.

@Mr DeMort, much thanks for your support, you are a true gent. If your ever up in sunny Scotland, drop in and I'll buy you a beer or three (restrictions allowing).
It's always a pleasure to help someone and im glad its fixed .. the method and you telling them what to replace and i'm not so .. along with the probable cost they charged you .

I guess .. its fixed is the main thing and as i already made my feelings know in my previous post i'll leave it at that :)

Its fixed .. :yahoo:

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