p0170 fault code help.
 

Hello there. I am currently having an issue with my A-class (2001) Y reg, 1.4L petrol.
I have got the dreaded p0170 (self adaption) fault code. have had it cleared once but has re-appeared. I am not sure what is causing the problem.
The car is running completely fine, not using to much fuel, no loss of power or any noticeable issue.
I would really appreciate any help at all on what might be causing this and any solution? It is deeply frustrating as have just bought the car (privately) and really like it. Any help would be greatly appreciated.
Kind regards from Guy.