Les Dawes

Hi, I have the PDAS fault light and ! light illuminated. Have tried all the usual fixes, ie. plug leads (yes they are very costly to buy) and my local independant Porsche garage has identified 3 unrecognised faults on their diagnostic computer. They have suggested the PDAS/ABS main electronic control unit could be the fault.Therefore I would like to ask the following :-1* Is there anywhere (worldwide) that can test and repair these2* Does anyone have a spare unit for sale (or to loan to prove if mine is faulty, in the UK)My car is a 1992 model, therefore I need a 964 618 126 01 (not 00) unit.Can anyone help, or advise on a UK Porsche shop that has experience of solving PDAS problems.Thanks, Les.

tbennett017

Do a search here on the accelerometers (cleaning/replacing) IIRC, some guys found success in cleaning the sensors..

dfinnegan

Does the high pressure pump run on start up?
How long does it run?
Does it run if you use the brakes?
Have you had the full hydraulic system bled?
Can you provide the fault codes your shop has found?
Is your hydraulic fluid level up to the max mark?
Do you have any hydraulic fluid leaks?

Computamedic

Les,

Can you describe the circumstances under which the alarm activates?? Engine running, driving, immediate, after some time etc. etc. If it's just the PDAS light and ! (and NOT the ABS light as well) the chances are that it IS specific to PDAS. Battery voltage and hydraulic fluid level are the first checks. If the fault is dynamic, i.e. when the car is moving, it may well be an acceleraometer issue or the wheel speed sensors.

Regards

Dave

Sten

Whereabouts in the UK are you?

Scamper

^^^^ what he said...

I had the PDAS/ABS and ! failure on my C4 and it was the ECU, there are a few places i tried who claimed to repair these units but no one could fix my ECU.

I tried these people;
Address:
ECU Testing
23A Church Street
Eastwood
Nottingham
NG16 3HP

Autotek (sales@autotekelectronics.co.uk)
: 0871 983 7424

ESC Alternators or BBA reman were others that i tried without success. It all depends on what the fault is....most will just charge postage or a testing fee if they cant fix it.

Eventually i bought one off ebay for £250 which was a bargain!! You could try the french ebay sites as they seem to have a few knocking around (last time i looked) at a reasonable price.

I still have my duff one in the garage but thats not going to be of much use ...

Les Dawes

Many many thanks for the replies so far, answers as follows;

tbennett - thanks for the thread

dfinnegan - pump runs on start-up as normal then cuts out as normal, takes a few operations of the brakes before pump cuts in again (proves it's not a pump/pressure problem), full system not bled for some time (but ABS works and 4-wheel lock engages and disengages OK, so all OK here), the shop's diagnostic computer brought up 3 "not recognised" faults - no codes displayed, all fluids OK and no leaks

Dave - spoke to you on the phone 2-3 weeks ago re. this problem, hoping to get to Donnington on Sunday for the meet-up - hope to meet/speak to you then

Sten - I am in Birmingham, in case you have a spare unit I would cover the courier costs both ways

Scamper - many thanks for the repair contacts

Car now booked in to J Z Machtech for 20th Dec, feedback from Steve McHale regarding the problem very promising, will update.

Les Dawes

Collected my car from J Z Machtech today, all sorted and back to normal. Fault was the main hydraulic pressure switch, located in the luggage compartment. This was the first time I had used them, and I have to say what a great outfit. Spoke to the guys before they started on the car, received a phone call when they had found the fault to discuss the way forward, also about the faults found when I collected, they were very obliging regarding when I could collect the car (bearing in mind the Xmas break), and the cost of the work was very reasonable. Cannot recommend them more highly. Many thanks JZM.

dfinnegan

Can you share with us how they diagnosed the pressure switch?

I'm interested because there have been a few cases of this switch failing; mine included. Usually there is a fluid leak. However, I did encounter the pdas and master alarm (!) some time prior to my switch failing. if there is a test to diagnose the switch prior to the leak stage that would be most helpful.

Congrats on getting it sorted.

Cheers,
Dave

Les Dawes

Dave, sorry but I did not remember to ask how they diagnosed the pressure switch. Mine had failed internally, but no fluid leakage. I was too relieved that the car was fixed. Give them a call, UK number 01923 269788. Regards Les.