2016 L405 SDV8 75000 miles. I've had it 4 years and 25,000 miles and it's been good. Last serviced March.

Driving today to a funeral and steering started feeling funny - a bit worried whether we'd get there. We did which was something of a relief!

Went quite slowly - twenty miles ish before we got there

Felt like there were only certain "allowed" positions - maybe 360 each one degree apart - so to go straight ahead you had to click back and forth between the two nearest to straight

Seemed OK parking really, so power steering has not failed completely

On the way back didn't feel "right" but not notchy as such

What might this be?

Mike

Not as easy to diagnose as you would think....


This is the Steering control diagram... a failure at any point will give issues....

Could be stiff universal joints in the steering shaft … common on other modern land rovers.

The electric assist steering works by means of a torque sensor where the shaft enters the rack area. The end of the shaft actually is slightly decoupled so that there is a degree of rotational play between the actual end of the shaft at the rack and the main shaft from the steering wheel*. So when you turn the wheel, the main shaft turns a bit before the rack end does. The sensors detect this rotational difference and will ‘assist’ the rack end to turn to match in line with the input from the steering wheel. How quickly it assists can varied which is why sport modes can be made to have a heavier steering feel.

It’s possible I suppose that the car is bouncing between each side o f that play and not sensing the slight movement in the wheel and so not assisting to hold a straight line. But when you turn properly it’s hitting the torque sensor and assisting.

Edit …..

Just thinking … the steering column sensor will also feed the info to car on what the steering wheel is asking for … if it’s gubbed or not providing accurate positions the the system may only be relying on the shaft rotating until it hits its limits… which would equate to looseness.

I don’t think I explained it well …. Sorry.

* after the play is taken up north end of the shaft will turn in unison. V8 or else ...

Thanks for your comments both

Interesting that twenty people have not told me "it's this well known thing"

I'm now wondering if it's tyres

I have Vredestein Quatrac Pros on it

Which are about half worn

https://www.vredestein.co.uk/car-suv-tyres...ATRAC-PRO/

I'm wondering whether it's jumping between the two different tread types on the tyres

If the winter and summer bits wear at different rates

Or something like that?

I've bought a set of Pirellis from F1 Autocentres in their "Sizzler" sale, should be fitted next week

Let's see!

Mike