help 964 electrical hell

[Guest]

since gettin my carrera 4 964 1990 when the computor brain is plugged in there is a weird shuddering through the gear box. have had no luck in getting this fixed what so ever. so have had to drive the car since the beginning with the wee computor box unplugged. No shuddering but no four wheel traction or abs ........ bit of a nightmare. porsche centre say it could be a gremlin in the electronics and wanted to replace the computor brain but at £2500 and also the fact they say it might not fix the prob didnt want to do that . George morrision of rutherglen is also confused by it ........ can anyone help pleeeeease

 

[bones]

Try and persuade a member to pop round and fit the brain to your car and see if it cures the problem. If it does buy one from a Porsche breakers. You might like to remind the said Porsche centre that they are responsible for any work carried out.

 

[Dave Wilkinson]

George,

I'm guessing that the ABS/PDAS processor is causing the PDAS diff locks to be activated causing the shuddering. When it's connected can the PDAS program be activated with the console switch?? Does the light come on?? Can you switch it off?? Can you hear the solenoids release??

It's possible that you may have a wiring issue with the switch causing the processor to do the wrong thing. If it were me I think I'd like to see some evidence of the switch operating correctly before I shelled out for a replacement processor.

The ABS/PDAS unit suffers badly from water ingress and I have seen very few reports of it actually failing. The contacts on the multi-pin plug also seem to suffer from corrosion and cleaning them up can have dramatic effects.

Ultimately, Bones' suggestion is a good one but if the problem lies elsewhere it may not prove much.

Wishing you well with the hunt for the culprit.

Regards

Dave

 

[Guest]

many thanks for your thoughts on me prob dave .... yes the light comes on your it makes a noise as if activating inside the car ... and just i think it works to get you out of snow and mud .... very weird driving if on and not on snow though ..... if anything else spring to mind please give me a shout ... and thanks for your comment so far ........ cool car by the way