Emission system message and check light

[WilliamEurope]

Hello from Spain!! My name is William and i have a S80 2.9 1999, 136.000 miles.
Four or five years ago comes the message "emission system needs service" and check engine light on. If i disconect the battery the fault goes, but after 140 miles comes again. It is curious, 140 miles approximatly it comes, always.
It´s very important that the car go OK. The revolutions are stable, not strumbles.... It run perfect. But light and message are there, always. Along the time, in last year I changed 6 candlesticks, 6 bobbins (over candlesticks), air filter, fuel filter, oil and oil filter, clean injectors, catalitic converter, two front sensors and gaskets of exaust system.... And no results.
In Volvo dealer computer diagnostics, the codes error are:
262A - adaptive combustible bank 2
272A - adaptive combustible bank 2
But the VADIS, code erros guide, gives many posibilities for these codes, and how the car go OK, no symptoms, it´s very dificult to locate the trouble. Then my cuestions are:
Why the fault comes always after 140 miles approximatly when i reset it ?
Anybody have this problem ?
Can anybody help me with this matter ?
It have "burned" to me. I had desist of looking for a solution, but I found this forum and I thought perhaps somebody can help me.
Thanks to everybody for to read this and thanks this wonder forum. And sorry for my bad english.