Today I noticed that the variable power steering boost is working weirdly on my 04’ XKR.

At slow speeds I am having heavy steering and at highway speeds it feels overboosted. Any thoughts?

 

Is this a new occurrence? I assume the answer is yes, but just wanted to check. My 2003 audi a4 acts the same way. I replaced the power steering fluid and it got a bit better (though I think the pump itself is just kind of toast at this point).

 

I am actually not sure if it is recent or not. I would like to have the heavy steering all the time. Although I would like it even heavier than the system provides in its heaviest setting.

I was wondering if what I am experiencing is normal or not. The car doesn’t feel bad at all, but my understanding was that the system was supposed to work the other way around. Heavy at high speeds and effortless at low speeds.

 

Ah, gotcha. Your pump might just be weak. Not that this makes me any kind of expert, but when driving without power steering (obviously not on the jag), I find low speed to be high-resistance and high-speed to be low-resistance (because the wheels are already moving, less kinetic friction or something).

I guess cheapest thing first--check the fluid. Maybe it's a bit low. Maybe it's a bit old. It's one maintenance item that's often overlooked. In the Audi, I'm pretty sure it had never been changed. It smelled horrid. In any case, an easy first thing to try. If it's livable, then it's probably financially not worth exploring further.

 

Is the fuse that controls steering assist, located in the dash drivers side, good?

John

 

I agree with the above. Sounds like your power steering is not working. Either the fuse has gone, as suggested, or the plug has come undone. You should be able to turn the steering wheel with one finger when the car is stood still.

This is how it happened to me click me to read.

This is how they fixed it click me to read

Let us know how you get on wont you?

 

Oh, no, I’m sorry. You all have horribly misinterpreted me. I can still move the steering wheel with one finger at low speeds, it just feels heavier than when moving the steering wheel at higher speeds. If anything I want heavier steering.

When I initially said heavy steering, I should have clarified that that is compared to higher speeds. It feels more weighted.

 

Ahhhhhhhh now I see what you mean. Got to admit I have never heard of this. As you say its reversed. The faster you go usually the lighter the steering gets. Sounds like literally the signal is the wrong way around?

Wonder what would happen if you pull the fuse? In theory you will get the opposite effect. Hard to move whilst stood still. Perhaps give it a go?

 

I agree with Frank - pull the fuse and see what difference it makes.

There is a very good thread here which describes how the system works and how to test it:-

https://www.jaguarforums.com/forum/x...ontrol-147084/

The input to the power steering is a pulse that varies with speed - I can't see how that could possibly become inverted, so any fault would lie in the servo itself. The thread gives the values you can test for to see if the system is working as it is supposed to.

 

What fuse should I be looking for?

 

Just checked my tires and the pressures were way off at the front:

right front was at 22 ps
left front at 24 psi
right rear at 28 psi
left rear at 30 psi

I haven’t driven the car yet after bring filling them up. Maybe those pressures affected my steering?

I haven’t tested the fuse yet.

 

The electrical guide for your car will show you which fuse goes to the Power Assisted Steering Control Module - on my 2001 the diagram is Figure 06.2 which shows that power comes from 14 II (Figure 01.04) which is Fuse #12 10A in the Drivers Side Fuse Box. Have a look at your own wiring diagram to see if that matches. On mine that fuse goes to the Aircon control module also.

Your tyre pressures might well be the cause of your problem though.

 

The moderators can now mark this thread as solved. It indeed was the tire pressures. I inflated the tires to 32 psi front and 30 psi rear and felt a marked improvement in steering feel. I was awestruck at how much of a difference it made.

 

When I saw the report of your tire pressures, I knew instantly that was your issue. Take the time to check your tire pressures weekly. That may save your life one day....

 

My impression is that this isn't actually reversed.

Normally it's harder to turn the steering wheel at low speed, so the power steering gives more assist there. At high speed there's less natural resistance to turning AND one wouldn't want to turn as far in the first place, so steering gives less assist.

On my car the power steering seemed to give more and less assist almost at random sometimes, so I might be using some tips here to troubleshoot that sometime.