[Gerinemo]

Not a huge amount of info on that particular fault on Peugeot
Anything I could see referred to the Rear lights / side lights or brake lights but it was just a quick google
you could check and see if any of the rear lights are gone as a start

How did you get that code was it diagbox or a generic reader ?
What year is the car

 

[Gerinemo]

Yeah check and see if all is working at the rear end including the high brake light and indicators
I would also take of the little plastic panel and see if there is any water ingress at the light cluster after all the soggy weather we have been having
Clear the code and see does it come back

Have read that some generic code readers dont work too well on Peugeot
J