Hi Marcus, I have had the OS fault light show up twice now on my +6 and like you can’t pinpoint any style of driving to be the cause.
Mine is also at the dealers - be interesting to compare.
There also appears to be little advice on what do do if the fault light illuminates.....
Mike

Interesting comments on the ZF box. My suspicion would be that much of any issue is down to the programming of the box being no different to that of a BMW saloon with traction control etc. Certainly when I had a Lotus with a Toyota engine, Lotus were adamant that they could do nothing to the engine or they would lose the Toyota guarantee and have to bear the costs of engine failures themselves.I wonder if MMC have the same issue with BMW or whether its just a problem of the complexity of re-programming the gearbox.

My experience of that ZF box was on a supercharged engine in the F type as opposed to a turbo engine as in the Morgan.. Turbos always come in with a bang after a bit of lag - zero lag is impossible whatever the manufacturers pretend. Combine that with a heavy right foot and no LSD or traction control plus a short wheel base and you have a recipe for doughnuts.

The only reason for having 8 gears as opposed to 6 is economy and the eco drive to ever lower fuel consumptions but the benefit is only achieved if the box auto shifts into very high gears at very low speeds. So the difference between drifting along gearing and spirited driving can easily be 3 or even 4 gears. I dont know whether the plus 4 does this but stamping on the throttle, dropping 3 gears and bringing the turbo onto boost in a light car on a wet road with no traction control does sound like a recipe for trouble to me. Or fun if you manage to control it. At least you have the engine in a sensible place - I found in the Lotus that once it went, there was no holding back what was for all purposes a rear engined car. Polar moment of inertia. Shades of early 911s.

Once the Welsh government lets me out of jail I must try a [plus 4 . Sounds like fun to me.

Howard,
the key here is not to have a heavy right foot. Drivers have to be aware that they control throttle, valve lift, boost and gearing, all with one pedal. You have to foresee the reactions of the car to your input and the delay of those. Having said that I admit that in Sport the automatic downshifts can be pretty hard, better only used in the dry for straight line overtaking. If you want to keep control over the rear, I recommend to use the paddels for downshifting and to have the gears sorted before you steer into the corner. Upshifts under load are smooth again. The ZF-unit in itself is not to blame, have/had that in compressor- and turbo-cars before and I like its flexibility from smooth early shifting to close to PDK-fast shifts.

Regarding the OS fault, visited the dealer today and the resetting required a recalibration of the trottle sensors. maybe the root cause of the fault? I'm under the impression that OS is more of a general fault indication which can possibly be caused by different more specific faults. Has anyone a recommendation for an OBD-reader with the newer BMW-specific codes?

Regards,
Markus

Yup, I had the same a few days ago.
A few days before that, driving on the motorway, I had a momentary loss if power, the engine light came on and went off again. I lost mpg only in the led display.
Both the above rectified themselves after I had parked fir some time.
Any views on this please.
Thank you

I am looking forward to a test of the CX cars when our lockdown allows. No dealer in Wales so it doesn't look like it can happen pre Christmas.
I do think that a heavy right foot when not used to the car response is a big contributor though. It was when I moved from 4/4 to Plus 8! Gradual learning curve sorted it out though. A few rear end twitches in the learning period. Mind you, it is the same with any car. Even downsizing to less power needs learning.