Josh B

I had some frayed connector harness. Replaced them already though with some nice ones that were squirelled away for just such an occasion.

I am wondering though for testing purposes if it would be helpful to have the main ABS harness out of that gold car? Maybe that would help me understand where I can test the harness in my car? These wiring diagrams can be hard to decipher.

Josh B

Well - fixed this problem but the issue is a little embarrising to share. There is a power lead from the ABS harness that comes into the battery tray. It goes to pins 6 and 12 on the ABS pump connector. At some point someone confused this as a ground and attached it at the battery cable ground. I moved it over to the plus cable and started the car this AM and she is good to go!

AScholtes

Good to know that you fixed it... hey oops's happen from time to time, luckily it didnt cause any other issues...

67King

Good to hear, but the misdeeds of prior owners is often incredibly difficult to fix - no sense in being embarassed by that.

cruise98

At least there was no smoke or permanent damage. Any other electrical issues with the car?!

kingston944

On my volvo I had to remove the ABS control module on the bottom of the ABS pump and resolder the main contacts where the wiring harness plugs in . Bosch control unit on volvo not sure what is used on Porsche but would think it is a Bosch ABS unit Volvo has not had an issue since . Check out ABS repair on google for volvo S70 ABS if that helps.

Josh B

It is a black cable at least

You got any exciting news?

Ben951S

You just saved my Bacon. Thanks for posting.

Austin09

Firstly I'd like to say thank you to everyone for contributing this has been really valuable in getting me started on the troubleshooting of my ABS.
I need some help with the next stage however.

My problem: ABS light is on permanently. Although it does flicked off for a split second moments after starting.

So far I've tested the relay and cleaned the terminals in the fuse box. There is 12v to the correct terminals in the fuse box and the relay works perfectly. This means the pump is fed with 12v (I assume a dead ECU would prevent this though).

If i bypass the relay within the fuse box, I can hear a clicking on the abs pump indicating one of the relays is working on the pump itself.

This problem did seem to coincide with changing the front brakes albeit a few days after so could be a coincidence.

I've removed the ECU and tested all the sensors they're all fine. This wouldn't cause the ABS to stay on before moving I believe anyway.

So my questions:
1/ Is there anyway to see if the pump runs by connecting 12v to terminals in the fuse box or ecu?
2/ Is there anyway to isolate this as an ECU issue?

Other posts say this could be ECU, which i doubt, or an ABS pump ground issue, which I also doubt.

Austin09

One other question sorry, where is the ABS pump ground? Do i need to take off the plastic shrouding under the wheel arch?

rahulsingh

Hi... My abs light is always on with ignition on , dash warning " brake pad worn out, brake fluid low,...checked the level sensor by manually dropping & increasing fluid level while taking resistance value with multimeter, I can read changes.. brake pads are ok, wires does not look bad either, I checked relay & fuse... The fuse was blown & while I put it back, light is still on.. checked the wheel sensor resistance at control unit, values are ok.. I cannot see any abs control unit in my tester( dramatic & autel), but I can see airbag, alarm & ECU reading in tester, so I thought maybe my control unit is faulty, checked power until control unit & ground, all are ok.. opened control unit to have a visual look, found all perfect at circuit board visually... What I should check next...
i have already checked brake pedal sensor, which is ok..
Thanks

Julian Allen

ABS ground is just below the body mount, accessible after removal of the fender liner. Don't forget there are two relays on the pump as well . . .