Citroen C5 X7 - Air Circuit problem

[DinuIoan]

Hello,

I have a problem that bothers me for some time with my Citroen C5 2011 1.6HDI. I went to some Citroen authorized services but none of them are willing to help me, they just took my money and that's it.

I have 2 error codes (found on my lexia - diagbox) P129F and P0401 that both says that is something wrong (permanently) with air circuit. It's a bit unclear what is really wrong.. I've changed my egr valve one month ago, and I've cleaned my MAF sensor with some cleaning solution from CRC, but the errors are still there.

I had also P0100 error code with message "Air flow messure", but after the cleaning of the MAF sensor that one didn't showed up.

Anyone some ideas hat it might be?

Thank you very much.

[GiveMeABreak]

Post up or PM your VIN as I need to know the exact engine and associated injection system. Then I'll also be able to shed some light on your other post - which I'm going to move to the diagnostics section.

[GiveMeABreak]

Ok, so here's what I have for these 2 codes - they look very similar, but do have some differences between them.

The fault says there is too much outside air going into the engine. So I would double check your Air Doser unit to see if this is stuck and allowing too much air in. The electrovalve may not be operating correctly. These problems could all be related.

So you have a few areas to look at now.

Click to Zoom and focus the Tables

[EDC5]

As Marc will probably know, I have had P0401 for a while and have confirmed that the volume of air measured by the MAF is indeed above the reference setting.

I put this down to a blocked EGR pipe or something but I'm not doing anything about it as it doesn't have any effect on the engine as far as I can tell.

However on my ECU (DCM3.4) it doesn't activate the warning light or cause any downgrade modes unlike your ECU.

I'd check the Air Doser but apart from that I'm not sure what else can be restricting the EGR flow?

[GiveMeABreak]

Yes this one’s the 1.6 e-HDi with Stop & Start and Piloted Manual Gearbox just for good measure!

[Bald_Eagle1]

Yes this one’s the 1.6 e-HDi with Stop & Start and Piloted Manual Gearbox just for good measure!

I know this is an old thread, so I'll start a new one if needs be.

Do you know if this issue was ever resolved?

I have exactly the same codes (P129F and P0401) on my DW10CTED4 2.0 HDI 163 engine, originally in a Citroen C5 (X7), but now in a Peugeot 308cc.

It runs great when started up from cold.
However, if stopping the engine for a few minutes and starting it up again there is no turbo boost at all, unless I disconnect the MAF sensor which makes it run great again.

I have tried 3 MAF sensors & they all give the same result so I'm ruling out a duff sensor at this stage.