I have the juddering issue in warm weather (so not at the moment) but wondered if it could be a duff temperature sensor issue. I just connected the IID to the car and got the following readings under the PCM engine section of the diagnostics:

Ambient air temperature 7deg
Engine coolant temperature 14deg
Engine oil temperature 14deg
External temperature 215deg (this is not a typo)
Fuel temperature A 12deg
Intake air temperature 8deg

The car is just sitting on the drive, and I can believe all of these except the “external temperature” which is clearly miles off and doesn’t vary.

Does anybody know what this reading is? Is it a real sensor or one of those loose ends that’s in the diagnostics but only connected on certain engines? I know it’s not the one that feeds the dash display because that reads 7deg in agreement with the “ambient” value.

I doubt I’ve magically found the cause of a fault that’s clearly been plaguing owners for years, but if anybody knows the answer I’d be very grateful! Thanks

What are the readings with the engine at normal operating temperature

Good question. Can’t take it out now but I will in the week and will log the same data

Thought I’d come back and advise I fixed mine via a Haldex filter service and oil change plus a ref lash that was available via SDD. No juddering since and that was a month ago (1k miles travelled)

Interesting, do you know what the software versions were before and after the re flash? I hope you’ve fixed it, mine only ever plays up when ambient temperature is mid teens or higher, so it’s been behaving all winter as usual. Expecting antics to resume in the spring, fingers crossed for yours!

Yeah mine was ambient temperature affected too. I assume that’s because of oil behaviour in warmer weather. It got progressively worse over 12-18months, before I finally pulled the Haldex fuse and proved the source. Haldex full service and the flash did the trick. Best in mind I changed virtually every engine sensor that could have been a cause before that. And flushed the transmission. And changed the prop, PCV, fuel pump, ….
I don’t know the s/ware levels I’m afraid but I’m sure it’s fixed.

Haldex fuse - that’s an angle I hadn’t considered. Is that the one in the boot labelled “electronic centre differential”? Never thought of pulling that one!

“Active on demand coupling” - see the fusebox diagram attached.
You will get a host of warnings and the car will revert to FWD only but in my case the issue disappeared which then drove me to a solution.

Fuse FB6 in the rear (boot compartment) fusebox.

Excellent thanks! Will bookmark that for when the hiccups start again

I had had this problem for the last 8 months, and I read every single comment regarding this fault.

Eventually, I started with minor fixes such as throttle body, fuel filter, maf sensor, engine and auto gearbox oil changes. However, I was nowhere. No codes were thrown, nothing.

The last thing I tried was the replacement of crank shaft sensor and the reader ring attached to the crank pulley.

And Bingo! The problem is now solved, and the car drives like brand new. Fuel consumption is much less, and anyone can tell the engine sound has changed for the good.

Unfortunately, I think due to stutters at high speed, I'm afraid autogearbox was affected negatively, as shifting form 4 to 5, it misses the gear for like two seconds and then rolls with full traction (it feels like the gear falls to neutral, and the engine revs up, and then levels off with traction).

For those, who suffer the same problem, I recommend you put the crank shaft position sensor somewhere near the top of your list.