2002. P38 4l thor/motronic. ABS, TC lamps

Grrrrrr said:

HUrry up. We're bricking up the tunnel at the moment ready for Brexit to finally happen.

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Grrrrrr said:

Hi Pete.

I've had a look at the NICO file. I think I need someone with WABCO D to check theirs, if possible. @wammers might have WABCO D?

On my WABCO C the brake switches are mutually exclusive, i.e. when #1 is OPEN then #2 is CLOSED or vice versa. They're never both OPEN or both CLOSED. Yours are. Is that normal for WABCO D?

Also, I reckon your front right sensor isn't following the others. it doesn't change much. Weirdly the rear left sensor voltage doesn't change much but it seems to realise the wheel speed is changing. Not sure what to make of that. Maybe @martyuk might have a better idea as he's played with these ECUs.

Excel spreadsheet I used to play with attached in the zip file.

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martyuk said:

I'm a bit late to this particular party, I know...

Firstly... regarding the WABCO D and Nanocom... there are a few inconsistencies/errors between the Nanocom data and what's actually happening on the vehicle, which I found years ago when I was playing around with the ECU's and trying to fix bits on my own RR. I passed them on to BBS, but as far as I can tell they haven't been updated in the firmware. I need to see what the latest firmware is and try that if I'm not on it already - but to my knowledge, there hasn't been any real changes in the P38 modules in the updates.

BUT what I have seen:
The brake switches - in real life/on the vehicle, they DO toggle - Switch 1 will oppose Switch 2 - rather than how they are shown in Nanocom of them both doing the same thing. It reads properly on the WABCO C ECU, but is incorrect in what nanocom reports on the D ECU. As long as they are both changing state, at the same time, then your brake switch is working properly.
Wheel speed sensors - I found that there is an issue with the labelling on the wheel speed sensors - I think 3 of them don't ACTUALLY relate to the wheel that they are displaying. If you were to get a fault code of "XX sensor" with XX being one corner of the vehicle - then this is TRUE and the corner listed is the one with the fault. Where things get confusing is that again the labelling in the Nanocom pages (at least the inputs page) are incorrect. Below is what label is actually what sensor (I worked this out by disconnecting one sensor at a time, confirming the fault code, and then looking to see which sensor wasn't showing a reading)

The Front/Right sensor on the vehicle IS the Front/Right sensor in Nanocom
The Front/Left sensor on the vehicle is the Rear/Right sensor in Nanocom
The Rear/Right sensor on the vehicle is the Rear/Left sensor in Nanocom
The Rear/Left sensor on the vehicle is the Front/Left sensor in Nanocom

I haven't had a look at any of the traces that were uploaded - but assuming that they haven't updated the labelling in Nanocom, it would be worth keeping in mind that what it is showing, might actually be a different sensor on the vehicle.

Regarding the ECU's themselves... the ONLY failure I've found on them (so far) is a component fault - which shows itself up as "LH Rear Sensor Short To Another Sensor" in the faults list - and it's a persistent fault - it won't clear, even if you hit 'clear faults' and it says it's done it. The ECU will also 'self clear' when whatever fault that was there has been rectified - I'm not sure if it logs old faults, I think that once the fault has been fixed and you drive it, if it's all happy then it clears them.

I've heard of a couple of people who have had various faults with the system - one of which was the sensor connection to the vehicle loom - he would get random faults, and traced it to one of the pins in the connector. The female side was just a little bit loose, so even though it was plugged in sometimes it would jolt just enough to break the connection and throw up a sensor fault. I've also heard of there being internal breaks in the wiring, and the copper bushings for the sensors allowing a bit too much movement in the sensor and that then causes it to throw random faults too that go away on their own.

Other than connections to the ECU/other ECU's/BECM fuse box, sensors etc, there are no connections in any of the wiring on the ABS system - it's all direct in the main body loom, so if there is an intermittent connection somewhere, then it's at one of the end points, and not buried in a loom/behind a panel somewhere - which is nice!

I'm not sure what other help I can be at the moment - but that's my experiences with the WABCO D system/ECU's and what I've found on Nanocom...

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supapete said:

Thanks again all. As I mentioned im forced to put this down till the end of may. Currently packing up to go back whilst, somehow, avoiding a divorce.
I sense, though, that the identity anomalies above-mentioned have in fact been ironed out. I loaded the latest firmware in. The rh front trace which shows no rotation actually corresponds to a fault thrown up, Rh front, when I disconnect in the manner mentioned. Now, thanks to you, I'm getting a better grasp of the subject, I'll recommence in a more structured fashion. Best regards. P.

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supapete said:

I'm sure we do. Perpignan, Bordeaux, Nantes, Rennes, Cherbourg. I'll check the map and report. edit A10 north of Bordeaux for a while. stop one night Bordeaux and one night Nantes.

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supapete said:

That's really nice of you. Thankyou. Our sites are booked and so is the ferry. I'm no good at shooting the breeze as so many do through France. But if a disaster befalls us watch out for a tow truck. Thanks again. P.

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