A person called Vic responded to a similar problem in February this year and got much praise - search on here - depollution system faulty.
This is what Vic said...
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I brought my pug for peanuts because the car had the dreaded de pollution issues which put the car into limp mode, the seller thought it was going to cost an arm and a leg to put right so sold it really cheap.
After some research I cured the problem for a total cost of £15.
Firstly don't go to Peugeot as they have no clue how to cure this problem they will tell you that it will cost hundreds to sort out to get rid of you unless your stupid and agree to get them to do the work.
DONT USE SUPERMARKET FUEL as its Shxxx and will clog up all the filters activating the fault, why do you think the fuel is cheap. Use BP, Shell etc these fuels cost a bit more but its cleaner and has detergents mixed into it.
To be eco friendly the French put another stupid sensor and filter by the catalytic converter which is the main problem for de pollution system problems.
SO TO GET TO THE POINT ON HOW TO CURE THIS PROBLEM.
1. Wait to the fuel level is just above the red then pour in a bottle of CATACLEAN into the tank. Drive around for about 20 minutes so this miracle liquid gets to where it needs to go then go to a petrol station and put in 15 litres of fuel. After a short while the sludge will clear and the car will drive how it should. I brought this product from Halfords but you can get it on EBay for a couple of quid cheaper.
Because of the poxy particle filter on French cars your going to repeat this process every three months otherwise its going to happen again.
LASTLY....
If the engine management warning light is activated because of the De pollution warning and won't turn off follow these simple steps to remove it
1. Press the TRIPMETER button (mileage reset) on the dashboard.
2. Keep your finger on the button while you turn on the ignition. Don't turn the engine on.
3. After 20 seconds the display will read "0"
The service symbol will extinguish and will turn off the management warning light. No need to disconnect the battery.
By following these steps I sorted my problem out and avoided paying hundreds to a mechanic who probably doesn't know what's the cause.
I hope this had been of help to you.
Clarkson
November 2014