Hi there,I would be so greatful if anyone could hand me some advice on my jaguar gear box problem.Ive owned the car for around 4 months and purchased the car from my father who had it in his ownership for over a year...all the time it was trouble free.Its developed a fault with the gear box now showing a light on the dash for the transmission putting the gear box in limp mode so the car only drives in 3rd gear with no option on using sport mode.The weird thing with the car is the fault came on the car driving to work,was still on comming back from work but later that night when I tried to start it up the fault had gone and drove perfect.I started it the next day and it was back on so I had it to the garage to have the transmission fluid and gearbox filter changed but the mechanic said it had not fixed the problem.To both our suprise when I got in the car to leave the fault had gone and it drove perfect.....that was until I drove around a mile and the fault came back putting the car in limp mode with transmission light on dash,since then the problems gone a couple of times but after around a mile of driving comes back!!I don't understand how it can be ok but then not on so many different occasions.When the cars in limp mode it's very aggressive getting it into a gear but when the limp mode isn't on its so smooth selecting a gear you don't even know its done it,I've taken the relays out and cleaned the connections up and disconnected the battery for half hour to clear the ecu but no joy...I'm a bit lost with it now and sadly starting to fall out with my xjs,I would be so grateful for any advice,thank you

 

Ryanxjs,

The limp mode is triggered depending on the type of fault code that is thrown. Turning the ignition on and off will often cause it to go back into normal mode unless the code is thrown again.

You need to take it to a mechanic who can read the fault code that causes it to go into limp mode. I agree that a fluid and filter change often resolves a range of shift problems. If that hasn't now cured it, you really need to get the codes read. The problem may not even be the gearbox. It can be an engine problem which causes misfiring etc and that can cause the car to go into limp mode.

Good luck

Paul

 

Many thanks for the post Paul,I've tried a few garages around my area but modern diagnostic readers won't work on my car I've been told and the nearest jag dealership is around 50 miles away so i guess my first problems sourcing a old style diagnostic reader and take it from there,thanks again Ryan

 

Ryan

If you've got a trip computer in the car, then you can read the error codes through that. If not, if there's a jag specialist (or any garage) who has a facelift XJS trip computer, then they can just plug it into the clock wiring plug and read the codes.

Hope that helps

Paul

 

Thank for your advice and time Paul,I will take it onboard and contact some different garages,the problem I find these days are mechanics aren't mechanics anymore......more technicians and only skilled in plug and play,thanks again

 

Ryan,

Try giving someone like Tasker & Lacy in Leeds and have a chat with them.

Paul

 

93 xjs 4.0 auto trans


My car is behaving exactly like yours is. Just scheduled a trip to Jag dealer for trans fluid and filter change. Like yours. Some have suggested that the transmission power relay or the transmission relay as a possible culprit, but they are not where they are supposed to be on my car (there are no relays over the right rear wheel arch) so far when the transmission idiot light comes on no codes seem to be thrown to my trip computer. Nice thing about limp mode is I am still as quick off the line as most traffic, and most of my normal route is 50 MPH piece of cake even in third gear. I will let you know how my fluid change goes. please give me a shout if you come up with an answer

Thanks

Al

 

Just got a call from the local Jag dealer canceling my appointment for a Transmission fluid and filter change. Apparently Jaguar of Fort Myers does not have the appropriate tools to do the job. Any Ideas for the so west florida area service on older Jags? Home owners association does not allow for work being done in driveway or under the carport.

Al

 

Took my car to Hunts Automotive repair, Fort Myers, Florida , ( specializes in repair of mostly british sports cars but also some Italian sports cars as well) ) When I took the car in I was told the rates would be $110 an hour, and he couldn't promis anything., forwarned I left the car for a couple weeks of testing/repair. After three weeks got a call that he had fixed the problem. turned out that the throttle position sensor also feeds info to the TCU it was all covered in oil and the Potentiometer in it was also drenched in oil. So he removed it and cleaned it up with a degreaser and electronic contact cleaner. reinstalled it and the problem seems to be cured. Sounds simple, but here is what was done prior to that. He tried tracing the signel wires to the TCU to their various points of orrigin making sure all connections were right, OHM ing the wires to make sure there were no high resistance connections, he "borrowed" a TCU from another Jag without improvement. he fixed several resistive ground connections. there was a list of several other common problem causing items. but he eventually did track the problem to it's source the throttle position sensor nd repaired it. I am sure he put in many more hours than he reported, and ended up charging me $750 for everything he did, including the oil change filter air filter, transmission fluid and filter. I was expecting to see a bill for two to three times that ammount. Great service great price and I am sure I will go back the next time some fix is over my head.

Al

 

Al,

Glad you were able to get the problem fixed. I suggest that you report your "local Jag dealer" to Jaguar Head Office in the UK. The "appropriate tools" to change the auto oil and filter are a ratchet and few sockets!! Jaguar HO will want to know why this dealer is refusing to work on your car.

Paul

 

Paul:

I am sure the dealer had the tools to do the transmission fluid and filter change, what they appeared to be saying they didn't have access t is a code reader for a 92 Jag, which is not a big suprize as it is just a tad old for the moddern codes(odbe2 or something like that). the local chapter of the southwest florida british car club pointed me in the direction of Hunt Automotive, and I far prefer dealing with him

Al

 

This has been a helpful thread for me. Thank you to all the contributors,
My 92 4L auto occasionally has a fit when at highway speed:- engine revs up, there is a lurch, then it settles back down to what was happening before, EXCEPT that the tranny light is on on the dash. I have been able to lose the dash-light by pulling over and turning the car off and immediately restarting. Then she behaves just fine. She has never thrown a fit twice in row. (This makes me wonder if the tranny fluid temperature is a factor) There is no pattern to this phenom.
If anyone can expand some more on this thread - it would be gratefully received.