Mission to resurrect 997.1

[Matthew Miller]

Hello Everyone, I have a very poorly 2007 997.1 RHD C2 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 now almost electrically dead. No ignition lights, no instrument panel, side lights, interior lights, no response to key now trapped in the ignition switch or to the remote button on the key etc. 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 all fuses 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 to diagnose and fix myself.
I am very keen to hear from anyone with knowledge of how to recover a porsche from a similary dead standing start. I understand RBrunelle has achieved this with a flood car and hope to hear from him and other members with ideas, tips and any connections you can make that may be able to help. Aside from checking fuses I have hooked up a fairly sophisticated 'Snap On' diagnostic tool to the OBD socket and found that no reading could be taken, the socket is electrically live but the bus is not responding. I've done a lot of reading of the monster thread on Chinese PIWIS 2 and reckon I may need one, before I buy I would like to know which used control modules I can fit and successfully code with the Chinese PIWIS 2 and which ones I will need to have Porsche code, will they code used units or must they be new for either commercial or technical reasons? Will the Chinese PIWIS 2 allow me to code my VIN to used modules? I lso understand there is a group of modules that can't be mixed and matched but I'm not sure which these are on ther 997. I've come close to finding answers to the above by reading lots of posts on the PIWIS thread and elsewhere but not quite nailed the answers I need so I hope you will forgive me if they are there and I've missed them!.
Thanks in advance for any help you can give.
Best rgds,
Matt

[jchapura]

I don't have any specific experience resurrecting a car in this condition but I can offer general pointers.

 

Did you smell plastic burning or melting when the over-voltage occurred? That would be a bad sign and wiring damage is likely. The resurrection becomes a lot harder if cables/bundles have to be assessed and replaced.

 

It is possible the over-voltage caused fuses and relays to be damaged. I would hand check every fuse with a DMM/continuity test. I would bench test every relay. Or just replace each and every one. Check or replace - just depends on if you have more money or more time.

 

After you've established that electricity can flow to downstream components, the next likely damaged component is/are the computers. I'm not sure if there's a business that can bench test them out of the car - if you find one - you may want to send them each module. When you find one dead - you'll have to replace it and then move on to the next module. An interim goal might be to get the module that directly connects/sends info to the OBDII connector (do they have that in the UK?). Then once that's working you can use other diagnostic tools (OBDII reader, Durametric) to get other modules assessed.