Hi all,

I have now fixed this... but I think many other cars have this problem - so just to share a diagnosis and fix in case anyone has the same trouble:

Symptoms: Engine cut out whilst away in France, whilst at speed. Scary stuff.

Car threw lots of error messages - DSC and ABS. I assumed electrical fault, maybe the modules themselves, a wheel speed sensor, ECU... maybe wiring.

I had also noticed that the wipers moved an inch every time I switched the ignition on by themselves for a month or so previously... but put it down to a quirk.. I realised that all three modules share the same earth point - the top one behind the headlights. Visually it looked fine.. I touched it (with my finger not a spanner) and it just fell off... corroded from the inside. Rerouting the wiring to the headlight/bulkhead bolt and all was resolved.

I think the x350 earth points are the cause of an awful lot of weird hard to fix error messages on these cars - most of which get fixed by new parts which may be less sensitive to degrading earth.. but the root cause remains. Don't wait... I would recommend upgrading/moving earth points as part of an ongoing maintenance programme.. its a quick job to do.

 

Yes this is a very well known problem on these cars. The ground studs usually just fall off as yours did. If you use a SS bolt to replace it all should be good.
Since it's an Aluminum body it has a number of ground posts scattered around the car.
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