The crank sensor is basically a service item on the Omega.
Along with the HBV, wishbone bushes and steering idler
A service item??? Really???
I don't know what you did with your Omega (when you actually owned one) to have the necessity to change those items at such an appalling rate
The 2.6 and 3.2 crank sensor is as said 90540743.
19 years of 3.2 and 2.6 ownership, plus numerous other 2.2, 2.6 and 3.2's owned on a shorter period basis, and approx.150k combined in that time, I've only ever had to change one crank sensor on a 2.2 due to failure, one set of wishbones, one HBV, and no idlers.
So to suggest they are basically service items is a bit extreme, to say the least....
Personally, my ex plod had two in 9 years. Both genuine sensors from a genuine VX dealer that I genuinely had to walk into. Once at 120k and again at 250k. In that time it also required two HBVs, at similar mileages. Likewise shocks. That car was owned and used by me from 2009/97k miles until 2016/270k miles... So plenty long enough to experience the full life expectancy of various components. Incidentally My first Omega cost £5,495 and required a clutch and cam covers in the year I owned it. The other 7 which form the basis of my ownership experience between 2009 and 2018 cost about £6,500 combined and some needed nothing, some everything. And those belonging to others that I have worked on, have all required much the same items replacing between 80-120k so take of that what you will.
The Omega was perceived by the market as being unreliable. The crank sensor was probably the single biggest cause of roadside breakdowns along with HBV failure and premature cambelt failure.
Add in all the other items that typically wear out between 80 and 120k miles and the list of what actually makes the Omega unreliable is pretty short. But the crank sensor and HBV are top of the list.
I suggest it as a service item because changing it as a matter of course at 100k is no different to, by way of an example, changing the water pump along with the cambelt on a VW Golf. The belt interval is 60-80k (depending on vehicle brand) but the water pump will leak and require replacing (with a new cambelt) at circa 100k, well before the next cambelt... Ergo you change the waterpump at each belt change.
So perhaps I mean preventative maintenance rather than routine servicing, but if you preemptively replace items known to fail as a matter of course, then the chances of an actual breakdown are significantly reduced. And if you include said items as part of routine servicing then a) you're less likely to forget, and b) less likely to suffer a failure.
Obviously that will be wrong, incorrect or otherwise contrary
but if you poll any recent/current Omega owners here, I would wager that at least half either carry a spare in the car or have one at home ready.