91 gearbox fault lamp

Got it plugged in by a good mate at my local jag dealer, and it came up with the red throttle body sensor under the throttle pot, Apparently it is a sensor assigned to the gearbox (hence why the gearbox fault lamp came on)He cleared the code and the lamp hasnt come on since, he tells me it can be a common problem if the vehicle gets left stood, but mine seems to have sorted itself, So if anyone else has a simmilar problem, have a go at replacing this red sensor under the throttle body pot.

Jobs A Saussage !

Awite i gots me a problem with me box of cogs. My 91 4 litre, now and again will pop the gearbox fault lamp up on the dash and it will go into limp mode. This fault can come on at any time, ive found that if i switch the ignition off and back on, 8 times out of 10 it will go off when i start it and stay off, and may not bother me again for mile after mile, and other times it will come back on and i will have to switch ignition on and off a few times till it finally stays off. ive checked the oil and its fine and the box selects and shifts as it should, My local indipendant jag specialist in Hull doesnt have the correct diagnostic gear, only the modern eobd gear so strugling to get it pluged in too

Any info would be much appreciated

Cheers
Dan.