C8 2.2HDi 170 Codes P0299 and P3008

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Peter Morgan
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Joined: 05 Dec 2019, 18:37

C8 2.2HDi 170 Codes P0299 and P3008

Post by Peter Morgan »

Good morning all. Looking for a bit of a steer if anyone is able

I've had the depollution fault message for some time - took car to Willmoths Citroen and they replaced the DPF (it was showing as getting full and had a separate message appearing about that). Codes cleared by them but reappeared within 10 minutes. Asked them to change fuel filter as I'd had that issue in the past.
Problem persists. Willmoths wanted car in for a 'day or two to properly diagnose, but that would have cost very dearly. Took vehicle to local garage who recommended replacing the Air Mass Flow Sensor and Map Sensor - all done, codes cleared, now reappeared

Car hasn't improved. Symptoms are very lumpy running when cold (like 'kangaroo petrol' syndrome with a learner driver) . When warm it drives fine but has no 'guts' - it's fine on level ground, but as soon as you reach an incline it loses mid range power and auto box changes down and revs excessively.

The car has 166K miles and so is not worth any further big investment. But I'd like to give it one last chance before throwing in the towel

Any ideas? Any advice will be gratefully received

Peter

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GiveMeABreak
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Re: C8 2.2HDi 170 Codes P0299 and P3008

Post by GiveMeABreak »

There's not much on the faults for this engine unfortunately, but those codes are:

P0299 Turbo pressure regulation: Pressure below reference value
P3008 Flowmeter signal: Air flow too strong

Ideally you would need to get diagbox on it and look at the live data to see if you can find out what's happening - which is probably what the dealer would be doing to try and pinpoint the issue, as certain problems can have a knock-on effect to other systems and create a false issue.

Peter Morgan
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Re: C8 2.2HDi 170 Codes P0299 and P3008

Post by Peter Morgan »

Hi Marc, thanks for your input. Is a Diagbox a Citroen-specific diagnostic tool? I have a copy of the diagnostic report generated by the local garage and it has exactly the definitions you quote above. When you say 'look at the live data' what exactly do you mean (sorry f that sounds dense)?

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GiveMeABreak
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Re: C8 2.2HDi 170 Codes P0299 and P3008

Post by GiveMeABreak »

Hi Peter

Yes Diagbox is the proprietary software used by PSA for all their vehicles along with the VCI interface that connects to the car and the laptop. With Diagbox, you can undertake certain tests or see live data to aid in diagnostic troubleshooting. As said a fault code may be triggered by the engine ECU because the data received from one sensor may be impacting another system, which then triggers another fault in another system. So as you can see, replacing parts based solely on a fault code may not cure the problem if the fault is triggered as a result of another system. So the live data can let you see the live data and readings of some of the sensors, which can be compared against reference values.

This can aid in fault finding and probably why the dealer would need to run some of these tests to see where the issue is. Sometimes it can be more cost effective if you don't have all the diagnostic kit yourself to take it to a dealer that has experience with these engines who may be able to troubleshoot the problem more quickly.

Peter Morgan
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Joined: 05 Dec 2019, 18:37

Re: C8 2.2HDi 170 Codes P0299 and P3008

Post by Peter Morgan »

Thanks Marc, that explains things a little. The trouble is, it feels like the dealer doesn't have the experience (I suppose the engine and engine management are now old school) and just plugs things in. I understand your point re: diagnostic approach but they actually said they would need it for one to two days - you'll have a better idea of likely labour costs of that. It may seem mean, but unfortunately the car only has a market value of about £1K (my problem I know!). I tried a local indy Citroen shop in Kent but they didn't return my calls - a shame because I imagine they are more used to seeing cars that are more than 10 years old and may have been likely to have a better idea of where to start looking...

Hagrid
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Re: C8 2.2HDi 170 Codes P0299 and P3008

Post by Hagrid »

If I may offer a thought; it would not (hopefully) take all of 1-2 days to wait for the fault to reappear whilst the diagnostic equipment was plugged in - you yourself talk of it reappearing after 10 mins. I very much doubt that the garage were intending to charge you for 1-2 days of labour; more likely an hour or so if the fault did reappear in that time. Keeping the car for a day or so would probably be so hat they could test it during a quiet moment in between other jobs. I may be wrong on nay of this of course!

Plus, although the PSA diagnostic program and equipment itself is extremely complex, if it s working properly them yes, you do just plug it into the OBD port.

Lastly, just to make extra clear what Marc said, 'live data' means watching the laptop screen as it displays all sorts of engine parameters on the fly as they are generated and are always changing, so that when the fault reoccurs, it is possible to see exactly what everything else was doing at that exact moment. It's like a teacher being told that kid 1 pushed kid 2 over in the playground - is the solution to tell kid 1 off or kid 2, or someone else entirely?