please can you continue looking for a solution to my question also my car is citroen Picasso c3 1.6vtr+diesel sorry for wrong information on original question thank you
this may be an issue with the FAP system
In the exhaust is a soot filter or DPF known to PSA ( Peugeto / Citreon) as a FAP. It runs very hot to burn some of the soot off every few thousand miles. It uses an additive is called Eolys and is stored next to the diesel tank with a computer controlled dosing mechanism.
If you don't drive it long enough, fast enough; then the regeneration process won't commence and the filter will block. Take it for a 40 minute blast down a empty dual carriageway; As you need to maintain above 50mph for around six minutes - that will start the process.
Alternatively; take it to your dealer or Peugeot specialist for a forced regeneration. If it's done more than 50,000 they will probably just fit a new FAP and top up the additive. this will cost £6-800.