Found on this forum, post by "senior member".

"Disconnect both battery cables and touch them together. Leave them touching each other overnight. Reconnect battery next day and everything will be reset. Codes, adaptations, etc..."

Anyone know for sure if this is valid or not?

 

Yep. Works for me every time, the Check Engine light at least, unless its not fixed. It'll work in about an hour, or at least when the capacitors are drained.

 

Cool beans, cuz my terminals were touching when I done writ the post thanks.

 

An easy way to confirm would be with an ultragauge. If the long term fuel trims change, then it probably works. At least for engine settings. Transmission adaptions might need a different scanner than can read live data from the TCM, to confirm.... but most scanners that can read that can also reset the adaptions.

 

I used to do this on my Jaguar, but it only took about 15 seconds. Didn't know it worked on the Disco, but they are Kissing Cousins, so I guess it makes sense.

On the Jaguar, I would also turn on the Key when the terminals were touching each other, just to be sure all circuits were open. Not sure if it made a difference, but thought it couldn't hurt.