http://www.computamedic.co.uk/Porsche/PDASABS.htm
hier nog een ander artikel
What you have is what we call here the x-mas effect... and the source could be one (or several) things. None of them are going to leave you stranded.
It could be coils going bad, distributor caps and rotors, plug wires arching, a bad or low battery...
Start with the easy stuff... clean and fully charge the battery. At night, raise the hood and with the engine running, spray a mist of water over the plug cables. If you see sparks you will know the wires are in for a change. Check the caps for cracks (or just replace them along with the rotors).
I really do not think this has to do with anything on the ABS or AWD system... when that goes bad you will know... back in June 8, 2000 I was using the car and had to make a sudden stop
at a speed bump. The ABS came to play. Since it was the first time I had sense the system in action I decided to give it another try. It worked flawlessly. Close to my house I made a normal stop and to my surprise the brake pedal would not respond. I had to push it extremly hard to make the car stop.
The problem was solved by: Pressure Sensor replaced(US$247.55 - Part # 964-606-904-00), Relay replaced (US$33.81 Part # 964-615-135-00), Rubber O-Ring replaced(US$4.99 Part # 999-707-094-40). Labor US$147.90 Minus PCA discount.
And you have nothing like that... so keep using the car, don't worry about it. Just make sure you do all these tests and start replacing those that you see are in need of attention.
Here is a thread of when I did the install of new cables, coils, etc...
Changing Spark Plug Cables
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het is dus niet makkelijk te bepalen wat het is.
robert