depollution system faulty :roll:

[Diabolical]

I have a problem with 06 C5 2L 16V HDi FAP I've owned car 6 months, go over 4500 rpm goes into limp mode for a couple of days then back to normal. I have never risked overtaking since I've owned this now really getting on my tits.

So Question is, if I remove and clean filter is this likely to help? also when I remove filter I assume I do it when cars NOT in depollution system faulty mode and will I have to disconnect battery?

However have new years MOT so tempted to remove completely.

David

[Lighty]

You cannot assume that it is the fap that is blocked, you need to get the car diagnosed 1st, could be a host of different things.

[Diabolical]

You cannot assume that it is the fap that is blocked, you need to get the car diagnosed 1st, could be a host of different things.

I've run Lexia scan through and no fault shows ??

[Lighty]

How long since the fault occurred ?, if you have been avoiding those revs for ages, it may have cleared. You may have to drive it hard until fault occurs, and then check, or run with live parameters showing.

[Diabolical]

Good idea fault occuring at the moment I shall run a scan today, though must admit I'm not that good with the Lexia. Only used it twice.
Could you explain the live parameters for me?

[Lighty]

After you have done a global test, you would normally check for faults in the engine ECU, ie, Read Fault, Erase faults etc, lower down is the actuator tests and parameters, click on Parameters, and it will allow you to select Standard , and a couple of other options. Select Standard, where it will let you chose Fuel, Air etc . A good one to view is Particle filter, as it will allow you to look at Exhaust Differential pressure, this should be zero at idle, and maybe a max of 50 mb at about 3000 rpm, if it is much more, this could well prove that your dpf is blocked. The Lexia will also tell you the soot level in the dpf etc.

[citroenxm]

You can not assume DPF or what ever untill the code is read, then this will give you a better idea.

The anti pollution Fault on the Cars OWN display is a generic message and can be related to exhaust, fuel feed and the fuel high pressure system at any point!

Can also be related to a possible Turbo Over Boot pressure. When the ECU detects too much pressure from the turbo say for example the wastegate is stuck closed due to a Vaccuum electro valve fault the ECU will put the car in limp mode to prtect the engine, this self clears sometimes itself..

[SaabC5]

Why would you want to go over 4500rpm in a HDi engine anyway, the torque curve falls off at 4000rpm so changing up is desirable.

[wheeler]

It doesent even sound like limp home mode, generally limp mode restricts the revs to around 2,200 rpm.

[Diabolical]

It doesent even sound like limp home mode, generally limp mode restricts the revs to around 2,200 rpm.

Limp restricts me to 2300rpm goes into limp mode when I go as high as 4500 sometimes 3500.

[citroenxm]

Turbo Over boost, it sounds to me..

[Diabolical]

After you have done a global test, you would normally check for faults in the engine ECU, ie, Read Fault, Erase faults etc, lower down is the actuator tests and parameters, click on Parameters, and it will allow you to select Standard , and a couple of other options. Select Standard, where it will let you chose Fuel, Air etc . A good one to view is Particle filter, as it will allow you to look at Exhaust Differential pressure, this should be zero at idle, and maybe a max of 50 mb at about 3000 rpm, if it is much more, this could well prove that your dpf is blocked. The Lexia will also tell you the soot level in the dpf etc.

Thanks when I get a chance I shall do that with Lexia.

This may help with problem though, today I could go to 5500rpm in 3rd! even though Depollution light was on also warning message coming up, now tonight after car has been run 4 times today warning has gone.
So I had another go at accelerating hard! 3600rpm back in limp mode.

[citroenxm]

Turbo overboost useually does do a what I call "Soft EML" ..

Which by that I mean it will reset with the Key off.. and doesnt need lexia to sort it out. However, Lexia will show you the Error recorded by the ECU so a Diagnostic is still in order.

I COULD still be wrong..

[zs&tas]

^ What he said ^

makes sense as its the only time something isnt right ( overboost ) apart from that everything reads and runs as normal so there is nothing to report.

[Diabolical]

Quick scan with Lexia Faults:

Permanent Fault.
Diesel temperature signal OC or SC positive (+)

Permanent Fault.
Pre-post heating relay circuit plugs never supplied

Temporary Fault.
Fuel pressure regulation to high

Cleared Temp fault.

Hope these have any thing to do with it so I can sort out solution.