Thanks John, I am busy getting ready company tomorrow and closing purchase of a '04 Maserati coupe.

 

Good Day
This is a small update, still no fix
1. Further research on the Icar 930 OBD reader disclosed two negatives. If you wish to clear a code, you must pay a fee. If you wish to add another non jag car, you must pay a fee of around $75 Canadian.
2. I am planning to buy a BlueDriver wireless reader (used in conjunction with an android phone), partly because it is a Canadian design (which implies no obvious preference for American vehicles)
The web site claims my specific car is supported and that extra, "hidden" codes will be revealed.
3. Originally I intended to do further actual tests but Canadian Thanksgiving and family activities took precedence
4. I will happily use the factory troubleshooting document - I have a spare desktop with windows XP still active and have downloaded the relevant cd images - crossing my fingers they will work (soon)
5 I suspect the failure of the application of direct vacuum to the throttle body is controlled by the safety feature that prevents such runaway by any rogue electronics.
6. I shall at the very least retest the switch using the supplied documentation
. I have the diags for the wiring systems - the are quickly getting folded from use
7. My thanks to all responders - I hope to resolve this issue before the weather changes and forces the car into storage.

 

That’s bizarre. Same business model as the dealer without the nice candies at the front desk.

 

I should clarify that P0000 issue - You are all correct, the actual display is P1000. My current OBD reader is an Innova 3100. I have been assuming that it is not capable of displaying all codes. It did show the one I generated from the throttle body and allowed me to clear it.
I am now wondering if the ECM is reluctant to clarify the "engine fault" code.
I have identified a new symptom, gleaned from another thread, specifically I hear an electric motor running sound from the upper engine area (sometimes) after shutting the engine down. Per the other discussion, it is likely caused by the throttle body motor. I was making a poor assumption that it was related to fuel delivery, possibly coming up to correct pressure.
At any rate I can't believe the throttle body has ever been cleaned. That will have to be addressed - I will look up the procedure from other related threads. The current issue is that my winter storage location is opening early and the car must be put to bed October 26th.
I have found recommended storage actions here and will follow them as much as possible.
This thread cannot stay open and idle for months, so I shall attempt to close it - with thanks to all who have assisted. (I may have to get moderator assistance to properly close )

 

Hello,
I was finally able to get the Jtis downloaded.
The general description of the cruise control states that there are three sensors on the throttle body and that if any one fails the cruise control feature is disabled.
The vacuum operated assembly mounted on the throttle body is used as a guard mechanism to prevent runaway if the electronics go nuts.
The cruise speed is maintained by adjusting the throttle motor, using two of the sensors on the throttle body ( I am assuming one measures "clockwise" rotation and the other measures "counter clockwise " rotation of the throttle plate)
It would be much easier to shoot this bug if the ECM could give a DTC code instead of the "engine fault" message.
At any rate I'll continue problem determination nex year when the car reappears from storage.
Thanks to all who viewed/commented.

 

If you are getting engine fault messages I imagine that there are underlying codes that your reader isn't picking up.

Something for you to read over the winter:

http://www.thejagwrangler.com/upload...management.pdf

This Jaguar paper on WhiteXKR's website explains the early cars' engine management system. Pages 1/7 & 1/8 in particular describe how the vacuum-operated cruise control works. The vacuum actuator attaches to the 'mechanical guard'.

 

Good Day,
I hope this post is still active. Newest update: The switch operated by the brake pedal for speed control has gone high resistance, preventing cruise control, but there is a more pressing issue . I finally got a friend's obd reader to display the error code P0568 which indicates a failure to read the correct resistance to ground. I have temporarily bypassed the brake switch. I removed and tested the switch assembly on the steering wheel. The holder assembly that mounts the switch card was cracked and had to be glued together, but the card is ok. The clock spring assembly was replaced last year for a horn issue. The ground point for this circuit is FC3BL. Could those interested comment on the location of this point? I am, hoping it is not covered with a complicated trim cover. The logical point would be under the panel by the left hand door at floor level. That panel will be rough to remove without damage because your are supposed to remove the kick plate assembly. That would mean ordering the stick on Jaguar decal at a cost of $100 Canadian.

 

Followed your post and found that you never found your problem?

 

Hello, I was able to get an error code, P0568 referencing ground point FC3BL per the wiring diagram. My current dilemma is that the car is in storage till some time in April , and I am hoping that someone can reference the ground point location. The trouble shooting pages apparently do not explain its location. I would be reluctant to drop the steering column, having worked under there, replacing the steering wheel positioning motor.
Any help you can provide will be much appreciated.

 

I had a similar problem but do not recall if there was a code on my 97. Looking at the wiring in the steering wheel I realized the cruise buttons grounded through the radio controls on the other side of the wheel and the ground wire from the cc was bent very tight and sometimes was open.