Disco 2 Auto Gearbox "Safe Mode"

Hi, I am new to this forum, I wonder if one of you out there can help, I have a 2003 Discovery 2, 4.0ltr Auto, recently the gearbox keeps going into what I can only describe as a "safe mode" whereby 2 x dash warning lights flash in amber, the "M" & "S" indicators & also the "D" on the LCD Display. It then seems that the gearbox only functions in third gear. The only way to stop this seems to be to drive for about a mile then stop, switch off the vehicle, switch back on & hope!
Any one got any ideas?
Sorry if this has been previously asked, but I could not find any other posts on this.

Phill

Yes this is the gearbox going into 'limp home' mode.

Most common fault is the XYZ swtich on the side of the box that tells the ECU which gear you are in. If it can't tell it puts it in 3rd as a default.

Sadly, my mechanic replaced that & it is still suffering!

You need to get your mechanic to do a fault code read then