Afraid not Sean B - British weather! As soon as I get a dry day and some decent daylight I will check this out. I see what you are getting at here though; an oil leak may result in poor shifting and moisture ingress will result in slip and electrical gremlins etc.

However, without seeing the trans connector, I know that oil is not escaping at any appreciable rate , as I have checked the oil level with the Merc dipstick gizmo quite recently. But I suppose it wouldn't require much of a leak to cause problems.

 

Hi...don't suppose you have anything to update?.......my 1998 xjr has been parked for months due to the p1797 and the addition of abs, handbrake, traction control faults flashing up for 6 seconds whilst the needles on the dash drop to zero, then it comes right again, but sometimes the gear box goes into spasm hence why ive not driven her and shes now out of mot which the tester wont re issue due to the abs light coming on when he tested her.......the git!!!

 

Replying to Howie; read through the following post for clues to your shifter problems.
https://www.jaguarforums.com/forum/x...problem-78781/
P1797 indicates nuetral switch malfunction
ABS and gearbox problems can be caused by the abs wheel sensors, clean them and the rings they work with, (links in forums)
The large connector near the ABS module can become corroded.
If the battery is undercharged/stuffed, it can cause the car to throw all sorts of fault codes.
Don't give up yet.

 

Thanks for your input mate.......just one thing tho......ive seen the p1797 code listed as you state but more often ive read its a canbus issue between the tcu and the ecu.........so is it a module or its wiring that's the issue, or is it something inside the box!!


Cheers.

 

Howie: the short answer is no, there is no update I'm afraid! The fact is that I never did track down what was causing the problems on my car; all I know is that it's now completely behaving itself.

The nature of these problems on my car suggested to me that they were almost certainly due to poor electrical contact somewhere. The last jobs I did before the car fixed itself were to use contact cleaner on the maf and throttle body areas. I also suspect that a p1797 code can often come up purely as a result of a can bus scan from a code reader.

Sorry that this isn't much use!

 

Additionally: it's interesting that you mention the dials going to zero then coming back. This is exactly what happens when my Autel scanner is performing a canbus interrogation on the various modules. This also tends to cause my trac/ASC/ABS failure light.

This suggests your problems are due to a poor electrical contact in a fairly fundamental area i.e power from the battery or a genuine canbus connection problem.

 

BLIMEY MATE!!...that's a gem of knowledge in its self......I've only noticed that the needles drop when I've had the OBD scanner attached as I took to driving her with the scanner plugged in to clear the code when the box went mental in traffic.......it never occurred to me that the two were connected so a big thanks for bringing that to light.......that's one symptom off the list.....one down!!

 

Also in addition: I noticed recently that a slightly seized/corroded/sticking rear brake/handbrake also caused a "Gearbox fault" message. This happened after I left the car parked on a slope with the handbrake on. After pulling away, a god awful racket was coming from the rear, combined with the gearbox fault message. After applying the brakes sharply a few times, this cured the problem!

I am guessing that the tcm compares data from the internal trans sensors with data from the wheel speed sensors to establish if there is slip or not. Other makes of car have a sensor in the diff for this, which should be more reliable.

This all leads me to believe that all sorts of spurious gearbox faults could indeed be caused by dodgy wheel speed sensors.

 

Hello,
Have you had any more issues? My 2000 XJR sympthoms have happened in this order.
1. Gear Box Temp " Limited Performance" - I turned the Jag off and back on after 5 minutes and cleared.
2. After passing smog check here in CA my O2 sensor failed.
3. While O2 sensor was out i heard a spudder come from the engine while acceleration around 35mph.
4. I fixed the O2 sensors and haven't had issues for 1 month.
5. Now i notice while i drive i can feel the gear shift when accelerating. Not when decelerating.