How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site. Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Matt Your Own Question
Matt, Mechanical Engineer
Category: Car
Satisfied Customers: 22756
Experience:  BEng hons Mech engineering, in auto industry 22 years
Type Your Car Question Here...
Matt is online now

My Citroen c5 diesel 2010 2ltr tourer , slight bang when pulling

Customer Question

My Citroen c5 diesel 2010 2ltr tourer , slight bang when pulling away , then anti pollution system fault came on , along with esp fault , pulled over turned ignition off , esp fault now gone , car runs ok but pollution system fault still showing , possible cause ?
Submitted: 3 years ago.
Category: Car
Expert:  Matt replied 3 years ago.

I'd 1st take a quick look under the car to see if the the pressure sensor or oxygen sensor in the exhaust has been damaged or knocked in some way

as a broken sensor will give a fault

if this all looks intact 'd suggest getting the car plugged into a diagnostic device to pull up the fault code and point to the fault as this will be a lot quicker route to repair

Also this may be an issue with the FAP system

In the exhaust is a soot filter known to PSA 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 citreon 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.