The same 2005 NAS V8 ..
Client has been reporting several times that his ABS goes into a braking fit in the morning, Meaning ABS will lock at very short intervals, like a downhill emergency procedure.
At last, after the car has been parked here for 5 weeks, we can reproduce it now, it will only happen when the car is cold (that means about 22ºC here) or has been parked for several hours.

It only happens on the rear brakes, they squeak and jam. After driving 200 m max all is back to normal.

No errors apart from the odd can bus error that is totally random.
Nothing I can see while the boss is driving with my eyes glued to IIDtool inputs.

Who has had something similar? What could it be?

No specific experience that is similar but random ABS faults I have had would be down to ABS sensor in hub/wires rubbing or also check the ABS control unit multiplug, top of the Left Hand side shock tower - the terminals on this can corrode causing random ABS activation.

Cheers,

Paul. 2011 TDV8 AB
2006 TD6 AB (Gone to Wales)

As above, check the wheel speed sensors on a graphing diagnostic tool or scope while rotating the wheels by hand (or driving) to make sure they are all providing a decent output. There should be smooth up and down increases in speed in line with road speed. Any skips or spikes in the graph indicates an issue (something just looking at figures won't necessarily be easy to spot)...any differences between them all and the ABS will think it's losing grip and kick in.
It could be an issue with the wiring rather than just the wheel speed sensor itself including, as mentioned above, corrosion in the ABS unit plug (a known issue on earlier L322's).
The 'tone ring' or 'reluctor ring' on the drive shaft CV joint could also be corroded (missing a tooth etc.).

Thank you very much.
I had checked the sensors previously and changed one that was not in top condition.
It was always showing a less satisfactory signal.

That was about 3 months ago.

But I found I at last 😁😎

Under the HDC and H/L switch is this little circuit board, which serves also for light in DNRP.
The toggle makes an earth bridge at the back of this.

Some plonker had 'repaired the HDC switch
This is what happened.

Don't worry just a diode and a bit of solder