Hi!

I am lucky owner of 1996 x300 xj6 4.0 sport. Sorry for my clumsy English and thanks for any advice. I will try to describe my mysterious problem. Initially I thought that it was a problem with the gearbox that seemed to switch in limp mode when driving a little bit more sporty, lets say with 70% throttle. Gearbox diagnostics service masters discovered that it is a problem related with kickdown switch. Diagnostics shows that kickdown sensor switches on at about 3700 rpm without accelerator pedal touching the kickdown button and gear shifts down but gearbox stays in the same gear (it doesn't switch further to higher gears). The problem disappears restarting the engine but recurs again if trying to drive sporty. Same happens if throttle / accelerator pedal has been pressed down to ~ 70% before driving (in position P). Maybe the problem is related throttle position sensor? Thanks!

 

As you have discovered, the kickdown switch lives beneath the accelerator pedal, and is a fairly simple device which, as its name suggests, is switched when the accelerator pedal is pushed right to the floor. There is a degree of adjustment which allows the point of its operation to be modified marginally. If it has been diagnosed as faulty, it would be worth addressing that first, as it would be relatively inexpensive and easy. Thereafter it could be more complex, but (for once!) I would not expect the Throttle Position Sensor to be a culprit.

 

Thanks for suggestion
I just think, is it possible that kickdown switches on for some error reasons without accelerator pedal touching the kickdown button? Maybe I can disconnect kickdown switch and check the situation? How do You think?

 

Good idea. Disconnect the kickdown switch see if your problem persists. Obviously, you wont have kickdown on command, but the absence of uncommanded kickdown would seem to prove the switch as the culprit.

 

Hi! Problem solved! It was kick-down switch stucked. I just pushed and pulled it in and out and thats it - works again )