On my 307 it can be done with a certain combination of button presses, but
I'd have to refer to the manual to see what they were. Does your manual
not mention it..?
Ivor
On my 206 it can be done by holding down the mileage reset buttone while
switching the ignition on and holding it down for a few seconds.
Yes, that is what the manual says.
However, trieded it many times without success.
The 406 is the same, just hold the trip counter reset button down
whilst turning the ignition on..
Believe it or not there are people on Ebay willing to take money off
you to tell you that(!)
djimbo.