it's a Citröen/Peugeot engine and most likely has the eloys fluid type dpf.
The 110hp model...if so I'll leave it
other common problem is leaking fuel injectors and text book turbo failure at around 120k if dpf isn't gutted and egr blanked to prevent oil from being contaminated with carbon deposits and dpf clogging causing cavitation in the turbo.
if buying your much better off purchasing a 1.8TDCi
no dpf and it's a Ford engine.
I have a 1.6TDCi bought unaware of the common problems,
Spent 1200 in preventative maintenance at 20,000 miles on clock and it's now got 180,000 on clock with no failures
still cheaper in the long run to purchase a 1.8TDCi