Wiring diagram and ideas to resurrect dead 997.1

[Wookie]

Hello Everyone, I have a very poorly 2007 997.1 RHD Manual Cab. In going through the emergency flat battery bonnet opening routine I accidentally put 24 volts into the loom via the pull out terminal in the fuse box. A costly lesson here to always reset 24/12 volt chargers back to 12v after using on 24 volt system. The car is almost electrically dead now. No ignition lights, no response to key in the ignition switch or to the remote button on the key. The only response is the automatic window drop/lift when opening and closing doors and drivers side electric window works. Apart from this all other electrical items are dead.
I have tested each and every fuse in the drivers side fuse box, all OK, and taken out and tested all the big fuses on the power distribution panel that is on the inside of the passenger side bulkhead, again all OK. There was no burning smell at the time of the incident and with the main fuses intact I am guessing something somewhere else has blown and stopped a high current scenario.
I prefer not to just tell a dealer to fix it so am attempting diagnosis and fix myself. I am hampered by lack of a wiring diagram and would appreciate borrowing one if there is a willing lender on the forum. Also very keen to receive your ideas, tips and any connections you can make that may be able to help.
I have looked at FAQs and Tech articles on the forum but not seen anything relevant, apologies if I missed anything.
Thanks in advance!

 

[BrianJ]

Oh dear, how sad. The only remotely relevant experience I have had was on my 986 when the installer of a new battery managed to put it in out of position by 180 degrees and then connected it up. Big flash (I was watching at the time). Amazingly it started up OK but none of the instruments worked and neither did the alternator. After fixing the alternator it all worked except the instruments. The whole instrument panel was replaced by OPC (expensive) after which it was all absolutely fine, much to my surprise. Let's hope yours can be sorted. Good luck.

 

[Ledlights]

Sorry, I don’t have a wiring diagram that’s of any use. I’m sure you’ve tried this already but can you track the 12V through to the board with a multimeter? If it’s dead you might find there’s a blown strip fuse that‘s located elsewhere…. I’ve seen one blow on a VAG car that was built into the battery lead connector.

 

[Geoff_Fields]

Extract from manual:
Power Distribution and Circuit Protection
Power distribution components include wiring, power
distribution and circuit protection devices. Beginning with
996 and Boxster (986) models, a power distributor is
installed at the bulkhead under the dashboard on the right
side in the passenger’s footwell. The power distributor
input is connected via a short cable to the battery positive
post. The power distributor divides the current into several
circuits through a series of high-current fuses.
The power distributor is used for these reasons:
• Provides additional protection against short circuits in
main power circuits.
• Dividing circuits near the battery positive post reduces
generator ripple and circuit interference in sensitive
circuits.
• Lighting circuits are divided into three separate circuits:
parking lights, driving lights and hazard warning lights.
One circuit can fail without affecting the others.
The power distributor in Cayenne models is located under
the driver’s seat next to the battery. The primary battery
relay on the power distributor has a safety switch incorporated.
In the event of an accident, the DME may
disconnect primary battery power via this safety switch. A
button on the safety switch will reset
the switch.
Note:
Work on the power distributor must be performed by
authorized Porsche service personnel. A sealing label is
destroyed when the power distributor is opened. When
service is complete, a special customer service label must
be attached to the power distributor.

Safety switch (location not known by me but ignore Cayenne reference) needs checking I would suggest.
Good luck!

 

[Motorhead]

Matt,

Sorry I can’t help directly in any way with your problem but you could try contacting Club Member (and 996 expert) Richard_Hamilton via a PM. I believe that he could well have access to the information you’re seeking and also may be able to give you some useful advice.

Good luck!

Jeff

 

[andywill]

HI Matt
As Geoff said above, if the 997 is the same as the 996 the power distribution board consists of 7 fuses 2x 50amp and 5x 80amp hopefully its one or some to them which has blown. I'm not sure if they can be replaced like a normal fuse but it should be easy enough for a competent person or auto electrician. The two following links may be able to help you locating things.
power distributor repair kit - Page 1 - Porsche General - PistonHeads UK
911uk.com - Porsche Forum : View topic - Power distributor pin replacement 997 .
Good luck & let us know how you get on.
Andy.

 

[Wookie]

Hi Brian, thanks for sharing your own experience and for the words of encouragement. I got stuck into it today and have made a small step forward. Nothing to get too excited about yet. I will keep you posted as I work through it.
Best,
Matt

 

[Wookie]

Thanks for sharing thoughts Steve. Yes I've done a bit of voltage tracing so far but agree there is more to do. Fusebox in footwell not receiving 12v, but main power ditribution board fuses that should supply the fusebox are OK so this is a puzzle! I see a later post that speaks of a safety switch, which I like the sound of.
I will keep you posted.
Best rgds,
Matt

 

[Wookie]

Hi Geoff, thanks for the reply. I'm totally fascinated by the concept of a safety switch, almost hyperventilating. I will certainly investigate that one further and keep you posted.
Best rgds,
Matt

 

[Wookie]

Hi Jeff, thanks for the reply and the recommendation, I shall certainly follow it up and I'll keep you posted.
Best rgds,
Matt

 

[Wookie]

Hi Andy, thanks for your reply. As you may have seen above from some of my further posts, to my surprise (and disappointment) the power distribution board fuses are all OK. I've checked them twice because I found it hard to believe! Geoff mentions a safety switch that should be checked which I'm intrigued by, just got to find it now. Will keep you posted.
Best rgds,
Matt

 

[Ledlights]

Hi Matt,
If you start at the battery, try tracking 12V on every feed cable from junction to junction. You should be able to find where it stops and you’ll have narrowed it down to the right spot. On the VW I worked on, the strip fuse was in an oblong plastic sealed unit and wasn’t obvious at all. That went because it was accidentally jumped from a 24V feed and took out all the ABS, traction control and stability management.

Hope this help,

Steve

 

[andywill]

Matt
The safety switch which Geoff refers to only relates to the Cayenne which has one fitted inside the distribution board.
Andy

 

[BrianJ]

Does it by some quirky coincidence have any remote similarity to this recent post? https://www.porscheclubgb...x?m=1094627#msg1094863

 

[Wookie]

Thanks Steve, this does sound similar to my circumstances, will do the tracing you recommend and see what it reveals.
Best,
Matt

 

[Wookie]

Thanks Andy, this is a time saver for me, albeit gutted !!! Maybe I should retrofit one bearing in mind I can't be trusted with a 24v charger.
Best
Matt

 

[Wookie]

Thanks Brian. Interesting post you reference, one to look out for in future but having checked and found that the power distribution board is live I can rule this one out. Your thoughts much appreciated.
Best
Matt

 

[malarcy]

Internet guesswork here......

a thought - try disconnecting the battery completely, leaving for a "cup of tea" duration and then reconnecting, perhaps some module has gone into a panic mode.

also - as an aside - an AA guy once did this on a neighbours jag (WITH THE BATTERY DISCONNECTED) short the positive and negative (CAR CABLES )battery connections - apparently standard fix for confused Jags and he reckoned he had done it on other cars - your milage may of course vary......

 

[malarcy]

Perhaps more useful - I see some reference to a REAR fusebox on the 997 - assuming there is one in the engine bay ( no 1st hand knowledge ) - don't know whats there but worth a check.

PS - I sent you a PM ( at least the forum software said I did ! ) - have a look and see if you got it.

 

[Wookie]

Hi Everyone, thought I would post a status report. Progress made but still a way to go!

Thanks again for your replies so far.I found a guy based in Slovakia who has a PIWIS and knows how to use it ! He supplied me with a set of used control modules coded to my VIN and with the matching security codes needed to get the thing started. He advised that you need ECU, Transponder Module, Steering Lock and Keys all matched. He coded and supplied them plus another ignition switch and gateway. The steering lock was a bit of a pig, I needed to dismantle lower dash panels to access it, and getting to the ECU with inoperative and closed soft top was also tricky, however once all fitted the car ‘woke up’ and started OK. I switched the original key blades into the supplied key fobs so they will operate the door lock and glove box lock OK.

To my delight the instrument cluster is working but I still have some non-trivial issues to resolve. I’m getting the following warning text messages displayed on the instrument cluster
Battery/Generator, PSM Failure, Soft Top not in position (to be expected), rear lid not closed (to be expected), System Fault Visit Workshop.

In addition there are warning lights lit on the instrument display for
Air bags, ABS.

Also the headlights are immediately on full at start up and do not respond to the light switch, and the front radiator cooling fans come on immediately at full blast, which doesn’t seem right to me when car is first started and idling.

The buttons for seat heating, rear window heater, PSM and rear spoiler lift/lower are inoperative.

Climate control is OK

Electric door windows and mirrors are OK

Just realised I haven’t checked the brake lights.

My contact was initially most concerned about the battery/generator warning and suggested first a new regulator which made no difference and then said it was possible the old regulator (if it had failed due to the overvoltage) may have damaged the replacement ECU he had sent. That was a bad moment! However he suggested I could get another ECU with same bosch part number (in addition to same porsche part number) and take the Flash and EEPROM chips out of the one he supplied and put them into this second replacement ECU. So having learned to hot air solder I did this and the second replacement ECU behaved exactly same as first replacement, car starts etc. but behaviour and error messages are unchanged. Finally I put in a full replacement decent used alternator, but again the Battery/Generator warning message remains. I should say that the battery is new and fully charged.

Feeding this all back to my contact he now suggests a replacement BCM but I think this will need coding to the car. if coding is necessary I’m not sure it can be done ‘off vehicle‘ so this is my next learning opportunity (to put it positively).

Any comments will be gratefully received.

Best,

Matt