i have peugeot 207 RC 2008 it shows Duplication Duplication fault what it m?

Are you sure it said "Duplication"?

I would suggest it actually said "Depollution"

https://howtomendit.com/answers.php?id=184371

https://www.ecutesting.com/common-faults/peugeot/peugeot-207-ecu-common-anti-pollution-fault/

https://www.honestjohn.co.uk/forum/post/index.htm?t=110253

fhstr
February 2020