What does this transmission screw do (td4 auto)?

Yesterday my freelander got it's fault codes read and there came an error regarding the transmission. Something with gear selection if I remember correctly.

My brother (and mechanic) told me this might be due to a one or two click turn of a transmission bolt which looked like it sets something. We were looking for the bolts for the oil change and found these after some internet browsing, but during the first round this nut got twisted a click or two.

In the image it is the screw in the middle of the picture, the brownish one.

If we know what this screw does we might just know if the slight turning could have caused this error. Anybody knows what it does?

Extra info: During driving I never noticed anything. It is just that for some reason last weekend I got quite the power loss. At some point the engine warning light went on and as far as we know the transmission error was the only fault code stored (generic reading, not a specific landrover fault code reading) so I am curious if this could have anything to do with it. (I am replacing the crankcase filter with the BMW cyclone, the thing is totally saturated with oil, I fear this was the/a problem. The EGR is clean enough, so this cannot be the problem).

It's the selector and inhibitor switch. The brown screw will turn when you move the gear lever. The gear lever controls a cable that runs to the bottom of yer auto, which moves a lever under yer auto, which controls via a rod (or something else because I haven't taken mine apart that far to know (yet)) which travels through the auto to the top where the selector and inhibitor switch is. As the brown screw turns it changes the switch inside which opens/closes switch contacts to report what gear lever position you have selected. Also contains the inhibitor signal which warns it not to start the engine if it's not in neutral or park. The auto's computer uses this information to know what to do with the auto, like select reverse with it's outputs to control the solenoids in the auto.

Make sure you use the correct bolts if draining and checking the level on yer auto. They're underneath.

What was to code and is the auto broke'd?

Thanks for the quick reply.

The car is not totalled, it still drives (although I decided not to drive it until the problem is solved). I do not think the transmission is the actual problem but I still think that as it gives a fault code something is wrong.

The fault code is P0705. It should translate as Transmission Range Sensor A Circuit, "PRNDL input", Gear position switch, incorrect outputs.

The lack of power is probably related to a different issue, I drove for over 2000 KM after the knob got turned a little. But as you describe what the bolt does I do think the sensor is somehow uncalibrated after turning it a few clicks.

Edit: We decided back then not to change the oil. When I got home I looked up the correct procedure here and managed to locate the 3 correct bolts. So no wrong bolts have actually been touched (except the one we are talking about here).

P0705 relates to selector/inhibitor switch signal being incorrect. The reading the computer gets is wrong. Check the gear lever physical position is the same as the dash display and the led's located by the gear lever. You may find you can't pull the lever fully back to 1, from P through RD42. Also put it in D and see if you can move the gear lever to the right to select sport mode. You may find the gear lever doesn't "slide" correctly into each physical lever position. As if it's on the edge of 4 but the auto's computer is told it's in D. To fix the problem you need to do a bit of trial and error to reposition the lever.

Thanks for the info. Both me and my mechanic really appreciate it as the car is very different from what he usually works on and a lot of parts are - at the moment - a bit strange for him.

I tried every gear (also the manual gears) and they all work correct. I wanted to try a little fiddling around with one or two clicks but as we ran out of time we did not get to it. As all gears seem to work fine I think it will work out.

I have to add, I was told it was a stored fault code but there was no date added. So it might be that the fault was from a long time ago all that time being stored in memory but actually solved somewhere in the meantime without resetting.

I think I solved the problem I was having by the way, it must have been the filter in the engine. Put in the BMW cyclone and poof, the problem just went away (I think). Awel, got another question but as it differs I will open another thread for it.
(Edit: questions already answered, for some reason when running without the top cover on the engine the most left screw hole leaks a bit of oil, seems to be normal and furthermore I was told that one loose connector somewhere around the engine compartment is normal also)

Thanks again.

Several people have had P0705. I've had it too. I think it occasionally pops up.