Porsche Enthusiasts Club Forum

Hi all, newbie member here (peter) with a little problem I hope someone can help with.

My 2004 997 runs fab but the red warning message keeps coming on only after about 15 minutes driving - "battery/generator fault".

So, have had both the battery (less than a year old) and alternator checked. Battery is 100% fine, alternator is at 13.9 I'm told should be 14.4? When parked up for a few days still starts with no problem and other than an annoying beep and the warning light coming on it drives great. Seems to make no difference if I turn fan/lights/radio off - thought worth a try...

Only comes on after I've been driving for a while - 10-15 mins, so maybe only when engine up to normal temperature.

Does anyone have any ideas what may be causing this?

Most obliged in advance - I look forward to meeting up with you when the madness has receded.

I know you've had it checked but smells of an alternator issue to me. Possibly a regulator with a heat issue.
It will still charge OK but may put the light on.
Alternatively, it could be wiring issue on the loom. But they normally don't do temperature faults.

regulator or rectifier in the alternator

Thanks for the replies gents. Sounds logical - especially as the battery is still charging and it doesn't appear until warmed up.
Most obliged. Pete