Jolting into gear and not changing up

[chisron350]

Hi folks,

My 2003 XK8, 4.2L jolts when put into gear; either drive or reverse and won't change up, dash board shows as "gear box fault" in yellow. There are other yellow fault warnings.

What do you think?

Ron Chisholm

[Astromorg]

I think you have to get the fault codes read. As the dashboard has a yellow warning for gearbox fault, there will be one.
You need to use a Jaguar capable reader, not a cheap little generic-codes-only scanner.
Without the code(s), you (and all who try to assist you) embark on a guessing game that probably promises expenditure, but not necessarily a solution

[andypryce]

Yup, you need to get the fault codes. You mentioned other warnings, what are they?

[chisron350]

Good morning both,

Thank you for responding.

The car is booked to have the rear driver's side wheel speed sensor replaced, the garage (not a back street operator) tell me they can't use the diagnostic computer to search for more faults until the wheel sensor is changed. At present the dashboard read out is showing: DSC fault, gearbox fault and an engine icon in the left hand display.

The sensor is booked to be changed on August 9th, the earliest they can do.

Regards, Ron C

[JimMann]

Hi Ron, what age is the battery in your car?

Jim Mann

[chisron350]

Good morning Jim,

New last October and showing in good state, I wish it is simply low voltage.

Regards, Ron C

[andypryce]

Hi Ron, the DSC fault is almost certainly the ABS sensor, so once that is sorted they should be able to scan again for other faults. As others say, lots of things can cause gearbox fault, in my case it was eventually found to be the rotary switch that sits on the side of the gearbox. New one from Jaguar over £700 but he fitted a good used one for £120 and has been fine so far. The other thing as many others have mentioned is get the gearbox oil changed, this can often be a cause of lot of issues. Good luck!

[chisron350]

Hi Andy,

Thankyou; that's good information and advice.

I had the gearbox oil changed at 54,085 miles, mileage is now 87,000 so should be OK, but I will consider once the speed sensor is changed and the next diagnoses has been reported.

Best regards, Ron C

[chisron350]

Good morning folks,

This morning after many days lay off the gearchange is working normally; no jolting into drive or reverse...here's hoping.

Ron C

[andypryce]

Is that after some work or spontaneous?

[chisron350]

Good morning Andy,

Entirely spontaneous...

It's often the way; garage the car with a fault and the display has cleared when you go back.

Ron C

[andypryce]

True, quite frustrating.

[chisron350]

Indeed, but often useful.

[chisron350]

Hi Andy,

Speed sensor replaced and diagnostics re-run... all dashboard faults cleared, everything as normal, no jolting into gear... all OK. Test run (15 miles) all working perfectly, a MoT pass and no advisories. A longer run next week should fully should settle things.

Is this really a "switch it off and back on" solution ?!.

Anyway thank you for your help and support... upwards and onwards.

Ron C

[andypryce]

Fingers crossed!