Both front hubs recently changed due to bearing wear.
ABS sensors didn't make it out alive.
However, Front Right threw a wobbly a few miles later.
Replaced under warranty at no charge.
However, the problem has come back again, again not present for garage test drive.

Nanocom says:
12-05 FRONT RIGHT SENSOR SHORT TO ANOTHER 012 TIMES

We have glove box out and WABCO available for testing of the unit, or multimeter and oscilloscope readings from the plug pins. Though the latter would presumably require some messing about to supply power?

All pins in the unit are shiny and free of green or blue deposits.

all the pins might be shiny, but do they touch each other, its very common in todays cars for this to happen. they may have spread a little when you removed them . if it worked before and now it don't thats the first spot to look, also make shore they are fully in and not being pushed out by dirt or a broken ABS ring.

I'm not exactly sure what you mean.

Unrelated to the ABS/TCS problem, we had water ingress in the passenger side foot well which took down the ODB port. Replaced pollen and plenum filters to cure the leak.

We removed the glovebox and the OBD was wet but the WABCO unit and all 3 plugs are bone dry and shiny. They are pretty widely spaced, I don't see how they could go into the wrong plug hole ...

Besides which, it all worked flawlessly before the hubs were changed.

I also don't see how wiring in the loom would have been damaged, except near the hub sensors. Where it should be obvious ...

I'd love some resistance or voltage values to probe for ... Or even just the pin-outs so we can find which pair of sensors the ECU thinks are shorting.

Diagram

Pinouts

If I remember correctly, resistance of the sensors is around 1.2kOhms although the one sensor short to another fault is a known one with the Wabco D ECU and it may just be pure coincidence that it happened after you had been working on the hubs.

Chasman wrote:

I'm not exactly sure what you mean.

the pins on the abs sensors down on the hubs and the reluctor ring on the axle is also a spot to look as this is where the reading is taken from for the abs sensor, just look down the hole and you can see it
why are you pulling the electrics out , am i missing something.

I had this same fault code on mine after i converted it to Wabco D. However its gone away and hasnt returned all summer. I do wonder if it was dampness/moisture in/around the ECU unit as my car does seem to have a bit of a leak, and the ECU and area around it did appear to have sort of a slight sheen of condensation... It was also popping a few other codes relating to the pump iirc.

Gilbertd wrote:

If I remember correctly, resistance of the sensors is around 1.2kOhms although the one sensor short to another fault is a known one with the Wabco D ECU and it may just be pure coincidence that it happened after you had been working on the hubs.

Hi! I'm glad to see you're still an active member here!

I'll pop out with a multimeter in a minute and check them.

When you say this is a known fault with the WABCO D, do you mean the ECU is faulty, or it is reporting a phantom fault?

mad-as wrote:

Chasman wrote:

I'm not exactly sure what you mean.

the pins on the abs sensors down on the hubs and the reluctor ring on the axle is also a spot to look as this is where the reading is taken from for the abs sensor, just look down the hole and you can see it
why are you pulling the electrics out , am i missing something.

You aren't missing anything. We were at crossed purposes ... I was talking about the pins on the WABCO ECU being shiny. You were down at the hubs.

Our garage had the WABCO partly unscrewed from the bulkhead then ran out of time, so we removed the final screw (damaged thread) and unplugged all three for a look to see if the leak into the foot well had affected it ... Dry as a bone, all pins and plugs pristine.

Going to check the sensor input plug pins with multimeter now. Should be 1.2k Ohms. I guess I'm looking for half that across a pair? Or maybe a zero resistance which shouldn't be there ... I gather they are two-wire.

Aragorn wrote:

I had this same fault code on mine after i converted it to Wabco D. However its gone away and hasnt returned all summer. I do wonder if it was dampness/moisture in/around the ECU unit as my car does seem to have a bit of a leak, and the ECU and area around it did appear to have sort of a slight sheen of condensation... It was also popping a few other codes relating to the pump iirc.

Thank you. It was bone dry and all connections pristine. It's very low mileage (<90k) and garaged most of its life ... Until we brought it to rainy Somerset Levels!

Find this useful PDF while Googling:

https://www.nanocom-diagnostics.com/downloads/preview/wabco-d-type-p38

Chasman wrote:

Going to check the sensor input plug pins with multimeter now. Should be 1.2k Ohms. I guess I'm looking for half that across a pair?

You aren't looking at half, they are wired to the ECU individually, so if you look at the diagram I posted above, you can test each one from the plug at the ECU end. From there you will also be able to test for continuity from one sensor to any of the others.

I mentioned the Wabco D known fault as Marty has found it in the past. It reports a fault as one sensor short to another but it isn't on the wiring, it is internal to the ECU. I know he has successfully repaired them in the past (it was on his website but he is currently building a new one as he updated the old one and screwed it up). but as he has now relocated back to New Zealand, sending it to him may take a while.

Chasman wrote:

Hi! I'm glad to see you're still an active member here!

and I'm replying while away on honeymoon.......

Gilbertd wrote:

Chasman wrote:

Hi! I'm glad to see you're still an active member here!

and I'm replying while away on honeymoon.......

Congratulations!

Nanocom reports 2.33 volts on left side sensors and 2.25 volts on right rear. 0 volts front right. I guess there's no point doing resistances?

There is as that will tell you if the fault is with the sensor (or wiring to it) or internal to the ECU.

FL (pins 1/2): 0 ohms
FR (pins 4/5): 0 ohms
RL (pins 7/8): 920omhs
RR (pins 3/6): 917 ohms

None show continuity to ground.

Assuming that is testing at the plug without it connected to the ECU, you have two short circuited sensors. Disconnect where the sensors connect to the cabling and confirm the short is at the sensor end and not on the wiring between sensor plug and ECU.