I'm back, 15 mos. later. Finally got my 2000 disco plugged in and got p0741 (Torque Converter CKT Performance or stuck off), p0734 (Gear 4 Ratio Incorrect), and p0722 (Speed Sensor No Signal). Symptoms: It will not move forward at all, it will only move in reverse when in low range. Battery putting out a consistant 14+ volts. M and S lights flash when you try to put it in any forward gears. when shifter is in 1 or 2 position the little red lights that are normally beside the shift lever stay by the D and blink. Any thoughts on what the fix could be, involve, etc.. Thank You

 

Check with a tranny shop, sounds like the XYZ switch on the tranny has failed.

 

And yes, the XYZ switch is a real switch, they couldnt come up with a real name for it I guess.
If it is not that then it is the MAF.

 

check your tranny fluid, xyz switch will cause it to run bad and not shift right, but itll still move, it sounds like your fluid is real low, either that or you have some clutch issues

 

I know this is a long shot being that this thread is so old, but did you happen to get any resolution? I’m having the same three codes and same symptoms

 

Maybe try the things posted above. If your issue continues, you should make a new post.

 

Yeah I’ve already done everything listed about minus taking it to a shop. Replaced trans oil and filter, battery and grounds are good, I’m going to clean the maf and put the XYZ switch back together but the switch looks brand new inside so I highly doubt that is it. Trying to get ahead of the curve here and ask someone with the same exact scenario what their resolution was. And if I don’t get a response and it doesn’t work when put back together, then I will make a new post.