ABS not working

[piotr]

I have got spare ABS module-I'm thinking to fit this and see what happen???

[twoqu]

Haven't had a chance to read throught this thoroughly but it implies a non functioning return pump means no ABS!

https://rennlist.com/forums/964-forum/853080-964-abs-pump-cheap-repair.html

[twoqu]

Some better pics here
http://www.porsche968uk.co.uk/techni...abs-refurb.php

[piotr]

Some better pics here
http://www.porsche968uk.co.uk/techni...abs-refurb.php

Good stuff buddy,thank you

[piotr]

So the ABS is really get on my fxxxxxx nerves now.I checked all wheel speed sensors,and all producing AC voltage.
Next thing- I just changed ABS module,and bleed system AGAIN .
And it's still not working

[GazzaG60]

id suggest geting on ebay and buying 4 p38 sensors. bout 12 quid each.

rears will be too short. i took the orgiinal and cut it and pieced them together. its only 2 wires and an easy splice.

with the new sensors comes the copper housing. cut ot smash the old sensor out, clean up really well andfit new sensor and copper housing.

50 quid and 2 hours or so rules out 4 sensors. i was lucky the first sensor i changed fixed the issue of light on after x hundred yards.

[piotr]

id suggest geting on ebay and buying 4 p38 sensors. bout 12 quid each.

rears will be too short. i took the orgiinal and cut it and pieced them together. its only 2 wires and an easy splice.

with the new sensors comes the copper housing. cut ot smash the old sensor out, clean up really well andfit new sensor and copper housing.

50 quid and 2 hours or so rules out 4 sensors. i was lucky the first sensor i changed fixed the issue of light on after x hundred yards.

It is some option,but just wondering,did you have any wornings on dash or fault codes?

[twoqu]

It would be useful to get access to either Vagcom/VCDS to interrogate the ABS ecu. I understand you can use the various channels to assess important functions including the wheel sensors. It could be something as simple as the brake light switch, earthing of the pump or some other electrical/mechanical issue. You could test these functions by using the schematic and a multimeter.
Better to test and rule out what it is not before unnecessarily replacing components that function.
Unfortunately I cannot link directly but if you go to S2 Central, technical, running gear, ABS, diagnostics - you will see what you can test from the comfort of your seat!

[GazzaG60]

i got abs light on dash and no abs and a softer pedal

mines a 91 so no abs diags. my system uses s2 bomb, s2 pas and lines, s2 rack, 16v abs pump, aby hubs and cv's

[piotr]

It's workin
I bleed the system A G A I N but also connected vacuum pipes to rear diff lock,took it for long road test and it's now working perfect.
So at the end I think it was ABS module,but to confirm I will disconnect the vac pipes and try again.

[twoqu]

Thats great news!
Obviously if the ecu detected somehow that the diff lock was engaged then the ABS would be disabled. I guess this could happen if the lever was not secured in the off position and heavy braking moved it.

[Tom_]

piotr: try it and please tell me..abs module is there under the back seats?or in the engine bay?

U think this yellow and blue hoses? Picture taken by irishs2

[piotr]

I will try it shortly and I will let you know .ABS ECU is under rear seat as well as Diff Lock control box.

[piotr]

piotr: try it and please tell me..abs module is there under the back seats?or in the engine bay?

U think this yellow and blue hoses? Picture taken by irishs2

When I say ABS module I mean the big unit under the bonnet where all the pipes going in to it-(just to be clear) and ABC control module-ECU is bolted on under rear seat.

[Tom_]

OK..clear now...I think, that the problem solved actually this new ABS module under the hood...