dkdm

My 93 has had a central warning (!) and ABS light on steady for a long time.

I swapped a bunch of parts over a year ago but never found the problem.

I'm going to fix this issue in the next few weeks and I need some help from someone who has been there.

Background -
When the light came on it was on all the time, from the time I turn the car on, no matter if it is moving or not. I don't hear the hydro pump doing its self check like it should.
I tried to track this down shortly after it happened so hopefully I can remember what I replaced. I have a 94 968 as well so I swapped several things, including all relays, ABS computer and then I purchased another ABS pump module and swapped it. I know this issue would not indicate ABS sensors but I ohm checked (or continuity - which ever was in the manual) them as well. PS all the electrical parts I swapped worked in my other car.
I have the 944 volume 3 service manual and followed it as much as I could
Questions -
1) Several old posts here elude to using tester (Durametric or Bosch). Can someone confirm they've used one of these tools on a 944/968 to do diagnostic check on ABS?

When I go to Durametric website it only shows engine and airbag for 968 but 964 show PDAS ABS. Is the 968 the same ABS as 964 (I don't think it is)?

2) The Bosch tester is listed as KDAS 003 in other threads is this the same as the service manual listed Bosch K7 - ETT 016.00/VAG 1516?

What exactly will this tester tell me? Will it do a full ABS diagnosis and point to item or circuit that is bad?

3) Is there a better Bosch manual for testing our ABS?

The Porsche service manual (944 V3 section 45) has been helpful but I need a little more such as testing input/output by wire number for power/ground circuits and ohm values for circuits between relays and computer.


Thanks again for any help you can provide. Luckily I still have the glove box and inner fender out. I just need to fix this issue.....

PorscheG96

I've not experienced any ABS issues so cannot answer your specific questions, but just wanted to make sure you saw this topic:

https://rennlist.com/forums/924-931-...ting-help.html

The individual components have proven so unlikely to fail that my hunch would be a wiring issue someplace.

dkdm

Thanks,
The OP in that thread is describing the same issue I have. I'll recheck but I think that wire running from the + bat was one of the early things I checked before swapping out the ABS pump.

I did just find this http://www.porsche968uk.co.uk/techni...abs-refurb.php
Which lists a way to bridge the ABS relay and also push power to the pump to rule out pump (and rule in a wiring issue). It was interesting to see that pin 15 gets some voltage sensor from alternator. I did have to replace the wires from starter-alternator-battery due to PO splice rigging.

Paul Waterloo

I was going to plug my durametric into my 944.....but just realized that it does not have the OBD connector. I had to reset the darn airbag warning light using some weird ground a wire method.

Anyways, I can't tell you if the durametric will work for you or not, but I can tell you that I now have two OBD connectors that connect to the durametric cable, had to buy one to reset the airbag light in my old car when I tripped it.

If you have durametric, or access to one, I would be happy to send you one of my piggy back round cables that go from the OBD-II connector to the OBD on the 968 so you can test it. If it works on your ABS, great, either send it back or buy it from me for $30.

thomasmryan

my last two issues, on other makes, was the wire section between the fender liner and the front strut. I assume fatigue from suspension movement.

dkdm

Paul,
Thanks I may take you up on that, I do have a friend with durametric (just need to make sure he doesn't already have the obd to obdII cable).

Thomas, Thanks I'm checking continuity from ABS Relay to ABS ECU and ABS relay to fuse #26. So far they seem good. I'll check continuity of wires from ABS ECU to ABS pump and then I'll try to check voltage on several of those.

ramius665

Dave! Glad to see you're still in the 968 game. Hope you can make it to Parade this year, we're going to be taking our 968 again.

As far as the Durametric tool, it does not//not have any interface with ABS on a 968. Just CEL and airbags and speaking from experience here.

I've got the 968 FSMs at the house, when I get home tonight I'll check and see what it says about ABS diagnosis.

I'm pretty sure I still have your cell number from the SLC Parade, if it's the same I can text you the pictures from the FSM or if you PM me your email I can send them your way via email.

dkdm

Aaron,
That's what I thought and that is what is listed on their website.

I'll shoot you a PM with an email.

Dave

dkdm

So wires to/from ABS relay to ABS ECU, #26 fuse, stop light switch, and ground are all good.

I tried to energize the pump (i the car) by applying 12v to terminal #87 (ABS relay) and to pin #28 of ABS ECU plug (unplugged from ECU) and still no pump sound - even after turning the key to on

Next thing I wanted to check was the wiring to the pump and I think I found the problem...........



What is weird is I replaced this pump about a year ago and I still had the same issue.
So here is what I think happened -
1) Wire harness to alternator/starter/battery was doctored by previous owner, sometimes I had volt meter not working until revs were up (classic case of little blue wire bad).
2) Missing alternator signal tripped ABS light and main warning.
3) I chased relays for ABS, swapped ABS ECU and finally put in used pump but no fix.....
4) On its own ABS hydro pump pin#12 broke (I hope while I was wrestling it in I didn't do that)
5) The hacked wire to alternator/starter/battery finally let go at the starter and I installed a new OEM (only available for "tiptronic" but it works-slightly longer). Of course now ABS has a different problem but I can't tell it's a different issue......

First thing I'll do is make sure my old pump actually works, out of the car, and then I'll clean the connector up and have a brake fluid bath

Paul Waterloo

I would say that connector looks very suspect. Good job!

968turbos2

There was a post about the airbag, abs ecu and dme not related on the 968. They are, they use a 12v signal to communicate with the tester. The harness you pictured have a 12v signal that comes from the ecu and goes to both the airbag and abs computers. If it does not exist, abs and airbag are disabled. The 12 pin connector passenger side is the junction, I found it on the wiring diagram. Just like rs232, they use the 12v signal pulled high and low to communicate when the tester is connected. The abs ecu will reset once 12v is supplied but the airbag will remain lit if that 12v signal is not present once and must be reset with the scan tool.

ramius665

Heavy corrosion = electrical issue. Looks like you found your culprit.

Jay Wellwood

Now there is a good project for those with electronic/computer savvy...a cheapo version of the Bosch Hammer would be a HUGE benefit to the Community.