ze_shark

My 997.1 GT3 started suffering abnormal battery drain (24-48hr) after a couple of episodes of excessive (but normal) battery drain. Attempts to start the car with a weak battery might have damaged something in the electrical system, but that's just conjecture.

Fact is that I now get a "System fault visit workshop" with a an electrical symbol in the rev counter display. Shows up every time i start the car. It runs fine otherwise as far as I can tell.

I undertook to read error codes with a Durametric cable & software and found many more than I expected. I cleared them, but the system fault warning comes back immediately, same for the codes.

I am looking for guidance as to which could point me to the root cause of the problem.

Engine module: no fault codes
Airbag:
- 80F9 unknown fault code
- C140 Communication instrument cluster (display)
- C158 Communication gateway control unit (CAN drive)
Front:
- C140 Communication instrument cluster (display)
- C158 Communication rear control unit (comfort)
- C130 Communication steering wheel electronics (comfort)
- 8043 Front lugg. compart. latch. hook (normal - the hood was open)
- 8001 Power supply
- C131 Communication gateway control unit (CAN drive)
- C190 Fault insturment cluster (comfort)
- C122 Communication driver's door control unit (comfort)
Rear:
- C127 Communication front control unit (comfort)
- C131 Communication gateway control unit (CAN drive)
- C140 Communication instrument cluster (display)
- 8001 Terminal 30 voltage supply undervoltage
Left Door:
- 8001 Power supply for central locking
- 8002 Power supply for power windows
- C190 Fault instrument cluster (comfort)
Right door:
- 8001 Power supply for central locking
- 8002 Power supply for power windows
- C190 Fault instrument cluster (comfort)

Any pointer to narrow down my search will be much appreciated.

Fisher

Before installing a new battery, which is the likely culprit, I would look for a current drain. Basically, start with disconnecting the battery. Use your DVM to check the impedance and write that value down. This should be a high reading. Higher resistance equates to lower current draw. This will show the cumulative value of the entire vehicle, as seen from where the battery is connected. This value will be different from one vehicle to another because electricity is FM (fookin magic). Also because different accessories have different standby current draws. If this value exceeds more than a few tens of milli-ohms, you could have a problem.

To further isolate a problem it will be necessary to separate the loads. If you have a suspect part you can remove the fuse for that circuit and take another reading from the battery connections. This is only one way of troubleshooting a faulty circuit. You need to give us some feedback on what you find before we can be of much more help.

Basically, if you have a low resistance value you can pull fuses until the resistance increases. If you don't find a circuit with high current draw, then install the new battery and wait to see what happens. If the problem raises its ugly head again...wash, rinse, repeat.

MC 968CS

Hi...I've had some practice with batteries lately.

In essence, firstly the level of parasitic drain of the battery in a 997 911 is massive. Just sitting parked for a week or more likely just over two, can drain the battery. It's not good but fairly normal in this car.

Secondly, once the battery has been totally drained, it very very likely damaged if it's a lead acid type, and should be replaced or at least sent back to the manufacturer for testing if it's the lithium ion type. Either way, once the battery is totally flat, they are not going to be the same......you very likely just need to replace yours.

My other cars don't have the same issues....just the 911 (and my 996 GT2 was the same). They eat batteries if you let them go flat.

I now use a ctek charger and leave it on trickle charge when car is sitting for more than 2 days......that is a lot cheaper in the medium term.

ze_shark

Thanks for your replies.
I should have perhaps mentioned that the current battery is new and tended to with a Bosch charger with maniacal attention because the car has wiped the two previous batteries so fast. My problem is that I would not even dare leaving it two days without a trickle charger. I have had the car since new, and it would easily hold weeks.

So between that change in behaviour, the "System fault visit workshop" ominous warning, and the correlation between that warning and the sudden abnormal drain, something's got to be wrong.
Measuring impedance and taking fuses out is a good idea. I just would hope that some of the fault codes would narrow down the search ?

gruppe75

I had a similar situation with the fault codes and the durametric scanner. I believe all of those codes are triggered by a low voltage error. They codes did disappear after driving a few hundred miles.

andrewgt3

Exactly this. Same charger as well. If I know the car will be sitting for a week or more, charger gets hooked up.

kiku

I just had to replace the factory Porsche battery on my 997.1, after sitting in airport garage for a week.

I noticed that possibly the cigarette lighter socket next to the handbrake doesn't shut off if plugged in (in my case, had an USB adapter I use to charge my phone).

Can't confirm if that was the cause, but I now unplug the adapter from the socket when leaving car parked for a few days without a charger.

arvedo

hello good night forgive, for posting my problem here.
I have a targa 4s year 2009, with problems in electric windows and central locking. It does not work at all. diagnosis only shows faults in some modules and mark same faults c122, c123. and it does not let you erase them.
Can you guide me a little please, thank you very much
help please

Jake Athorn

Hi arvedo .
Did you ever get to the bottom of your central locking and c122 and c123 error codes as I have same problem on my 2005 Boxster
Kind regards Jake