I had a recurring brake wheel sensor fault (the sensors look very fine) which I am now thinking is caused by a camber (vertical) miss-alignment. Maybe someone before me drove up a kerb and bent the suspension. The bent gear is only noticeable as the tyre becomes worn at the outer edge by driving. I replace them as a new pair once a year. Except for this last time as I renewed the right hand and flicked it to the left ...
I think the brake wheel sensor has something to do with the speedometer; maybe the sensor even provides the speedo with its readings? So, I wonder if the isalignment can trigger the speedometer ---- fault that I started reading. Then came a transmission fault. Flashing transmission fault light each trip with the vehicle going into winter mode.
However, after replacing the tyres to new yesterday these faults have not yet appeared ...
If this is to be long-lived good news for 'me and my darlin' vehicle', I wonder if a) the wheel sensor gets tripped up due to a miss-alignment, b) as the tyre wears out can there be such a sensitivity to the imbalance that faults are triggered?
Cheers

Other things to look at:

If the front struts wear out, the alignment will be out. On my 1996 854, the strut spring mount (that large rubber thing on the top of the shock) was broken and the steering pulled to one side. To test the mount, grab the very large nut at the top of the strut in the engine bay and try to turn it clockwise. If the whole assembly turns easily and does not spring back to its original position, then the mount is dead. The power steering made corection almost too easy, but the tire wore much too fast.

Control arm bushings do not last forever, unfortunately you need to replace the entire control arm on these new cars. At least it is not a most difficult job.

The steering bushing also gets soft with age, a reasonably 'easy' job to replace and will make a world of difference.

I realize parts are expensive down under, but new tires every year are not cheap either.

I own a Macphearson spring compressor, so I easily replaced the strut mount. A couple of months later, I replaced the front struts(shocks) and that made a world of difference.

If you live where the roads are bumpy, I suggest talking to a shop that that can inspect the front end see if they can fix it for a 'reasonable' cost.

Some day, my wife and I will get to Kiwi land. The problem is that I would think that 2 weeks is much too short. We might have to move from our house to a condminium or town house so that we wouldn't have to worry about being away for a month or 6 weeks.

Merry Christmas!

One of the Brickboarders ownes a 2004 XC70. His ABS light came on and the speedo died. He lives up here in Minnesota where it has been bitterly cold, think highs around -10C and lows at -30C. One of his sensors was coated with ice and was no longer registering. He removed the ice and all is well again.

So, yes, the sensors do affect the speedometer and transmission by default.

Thank you Klaus

Those temperatures you mentioned are cold. New Zealand is very mild in comparison.
Wheel sensors are expensive little buggers. Also hard to tell if they are faulty or not. I have cleaned all around the area and also taken each sensor out and washed them. My first warning light to appear before others is the wheel sensor (P1633). I have already re-soldered the ABS module pins.
It is a 1999 XC wagon. You can tell it used to be a luxury car, the weight of it and smooth ride. Well, mine was until a shudder started happening at 30kph. But that is another story.
Thanks for your help. Keep warm this winter. Although, where I am, it is now summer and we are going to the beach. Happy Chrsitmas!

An alignment has nothing to do with wheel sensors. Faulty wires or very dirty sensor rings (on the axle) might.

But do get an alignment as your tires should last at least 50,000 miles. But only get an alignment where they have a machine on site.

BTW, what year is your XC?