Hello everyone. I am an new Jaguar owner and new to the forum, this will be my first post. Any advice your able to offer is greatly appreciated. Just recently I purchased a 2004 XJR. Yesterday I noticed my steering wheel was hard to turn, like the power steering was not working only at low RPMs or at an idle. Once I start driving and the RPMs increase steering returns to normal. Have no belt squeals. The power steering fluid is not low and right where it needs to be. I'm thinking, is my power steering pump going out on me and is there any way to confirm.

Any assistance your able to offer is greatly appreciated.
Travis in Las Vegas.

 

Welcome to the Forum!

If the belt is at the correct tension and the power steering fluid is not low then there is the possibility that the pump is worn.

I have not seen that on these cars tho in this forum.

How many miles on the car?

 

Car has 133K miles

I had not considered belt tension, this could certainly be an issue worth following up on. Is there any way to determine if the power steering pump is performing properly.

On a side note, probably has no bearing on my power steering problem. Last week I repaired a transmission leak by replacing the transmission pan and changing the fluid following the procedure provided on the forum using an infra-red thermometer to determine proper fluid levels at 40 degrees C.

 

The transmission work is only an issue if you "hit" something while the work was being done but unlikely.

Was the power steering an issue before you did the transmission?

You could try flushing and refilling the power steering fluid especially if that has never been done as the fluid may well be compromised by now.

 

Jackra_1, Thank you so much for your comments, most helpful. No the power steering problem was not an issue prior to the transmission flush. I will try flushing and refilling the power steering fluid. I don't know how this is done but am confident I can find a post on the forum

 

Seems odd that the problem started after the transmission work. Who did the work and was it a flush and fill or simply an empty the pan and refill?

If it was a flush then I can see that something untoward could have happened to the power steering lines and cooler as all lines get fairly close up front. If there is a leak even small so that air gets in to the pump it will lose efficiency.

 

I don't know that the transmission work and the power steering problem are related, my thought is not but thought it might be worth mentioning just in case. As for the transmission work, I did it. It was not a complete flush but a drain and refill ( about 4 quarts ) following instructions found on the forum using an infra-red thermometer to determine proper fluid levels at 40 degrees C.

Do we know if the transmission and the power steering system are connected and share the same fluid? One more thing, after filling the transmission, something odd happened, only twice so far, I am still monitoring this to see if it reoccurs. The car operated perfect for about 30-40 minutes, then it stays in 3 gear and wont shift. I don't think this is a limp mode, it just starts in 3rd gear and does not shift up or down. I get the " gearbox fault" message on the dash, no red light and no code as far as I know. The next day the car starts and operates perfect again. This has happened to me only 2 times, and I drive it daily but only short distances, maybe 15 minutes to work so this is too short of a period of time for the gearbox fault to come on. The very next day after the transmission gearbox fault came on I jacked the car up to what I think was level, drained out about 1.5 quarts of fluid and refilled about the same 1.5 quarts using the infra red thermometer at 40 degrees C. I've only had this car a couple weeks, am at a loss, and would hate to take it in to the dealer for what might be something simple.

 

Transmission and power steering completely separate from each other.

When you did the transmission fluid change did you replace the pan which has the filter in it and also the mechatronic sleeve?.

4 quarts of fluid is not a lot to drain from these transmissions as they hold 10.53 quarts including the cooler.

Many people get more than that if they let it drain for quite a while. I think I have seen people get maybe 5-6 plus quarts.

I did a complete flush and changed the sleeve as well as the pan/filter.

Some people have had trouble re-seating the sleeve as it can be tricky thus causing electrical issues as well as a leak.

So two separate issues the power steering and the transmission.

Some people have had their transmissions re-flashed, after a fluid change, to have the software updated with some success but that is usually a dealer or a good independent shop. But first things first.

 

Jackra_1, thank you for confirming transmission and power steering are separate. When I changed the transmission fluid I used an OEM ZF transmission pan which I believe includes a filter, I did not replace the mechatronic sleeve. I have wondered if my car was not exactly level and possibly did not replace enough transmission fluid. I do get a little bit of a growl from the power steering pump when I turn the wheel and not moving and assume there is no real way to test if the power steering pump is working properly or not.

 

One has to get the car level for this job.

So if the mechatronic sleeve was not touched it should not be an issue as it was not before.

You could always try some additive to the power steering fluid to see if that helps. I do not think you have anything to lose by doing that.

Try putting a tube deep into the reservoir to draw old fluid out and replace with additive. Look at the fluid carefully when you draw it out.

 

The degree of power assistance on these cars is controlled electronically, and essentially it should be maximum at slow speeds. It is called "Servotronic", and works as follows: -

- Road speed is transmitted to the Front End Module (FEM) via the SCP Bus
- The FEM calculates the amount of current to supply to the Variable Assisted Power Steering (VAPS) solenoid using a power steering effort curve data stored in memory. This solenoid is part of the Servotronic transducer that is attached to the steering rack.
- The VAPS solenoid controls the hydraulic effort based on the current supplied to the Servotronic transducer.

So attention needs to focus on the electronics. Is the cabling to the Servotronic module on the steering rack OK ? Some dismantling may be necessary so that cable continuity can be checked between the FEM and the Servotronic module.