DPF pressure sensor

[vileorange]

Hello everyone.

Is is my first post here and I need some advice.
I recently bought Citroen Grand Picasso 2015 1.6 diesel with a "normal" autobox. The car drives ok and I don't have any issues.
I got myself an OBD device with FAP Android app just to see what is going on there.
For some reason, the DPF pressure sensor is showing a weird value that is too high. I went there to see if there is something wrong with the sensor, but I could not find it. From the internet, I learned that it should be just above the alternator, but there is nothing there. No pipes, no plug, no sensor. I did not have a chance yet to raise the vehicle to trace the pipes from DPF to sensor. Start-stop feature stays turned off at all times. There is no error codes or messages on the dash. Recently add 7 liters of Ad-blue just to keep it topped up. Battery is over 70%. The car did 106000 miles

Tomorrow I booked an "Ultimate Safety check" at my local Citroen dealership
Please advise

[GiveMeABreak]

The pressure in the particle filter will rise - that is expected, as the filter becomes full of soot. Then, after regeneration it will fall back again. This is how it works.

What isn't normal though is that your filter is regenerating on average every 4 miles! Do you leave the engine running whilst stationary or do extremely short journeys?

The filter shouldn't be regenerating every few miles..... what sort of journeys are you undertaking?

These readings would suggest the filter is getting near full capacity and is remaining full after regeneration, which usually means it is full of ash which can't be burned off.

Might be time to have the filter checked and cleaned out assuming the readings are correct and there isn't a problem with the sensor. 106k miles is getting near the life of the particle filter which can vary according to driving conditions.

[vileorange]

Hello, thank you very much for your reply.
I don't drive too much. For last 2 weeks car been mostly stationary. I drove few times on the motorway (under 50 miles) and localy to get some adblue.
The pressure according to that program is higher that turbocharger pressure.
Car drives without any issues and is quite agile if you put the foot down.
According to Citroen website this car has 2 recalls pending. I will see what Citroen dealer will advise tomorrow.
Is it possible to locate the pressure sensor without jacking up the car?

I forgot to mention that pressure stays constant at all times

[GiveMeABreak]

The turbo pressure has nothing to do with the particle filter pressure.

The particle filter has upstream (a) and downstream (b) pressure sensors for which the pipes for each are shown below. The sensor itself is located in the engine bay.

See what the dealership says, but I suspect at this mileage they will advise on a filter replacement. You can have them deep cleaned. There are places that can do this, but you will need a professional level diagnostic tool to advise the engine ECU that the filter has been replaced if you do opt to clean the existing one. I doubt the FAP app can do this.

[vileorange]

Thank you, Marc, for your time and effort.
Would you say from the height of your experience that pressure is way too high for the car to start? Given the fact that pressure is always constant could it be that someone somehow changed the program in the car to trick it not to show any fault codes?
Something tells me that something is really not right here either with my diagnostic method or the car itself. I got about 2 weeks left to return the car back to the dealership I bought it from....

[RichardW]

There's only one sensor, it's differential. It's on the firewall behind the battery somewhere. I wouldn't trust values from a device like that - if the car is happy, leave well alone!!

[vileorange]

There's only one sensor, it's differential. It's on the firewall behind the battery somewhere. I wouldn't trust values from a device like that - if the car is happy, leave well alone!!

Thank you very much, Richard. I am just worried that's all. I browsed internet for DPF problems and it seems that 35-50 mbar is when people start having problems. Mine shows over a 1000mbar and it always stays the same regardless if car is running or not. I will see how much dealers diagnostics cost and what they say about pictures above. Also start-stop is off permanently and impossible to turn on. Again 0 codes.
Since I bought the car there was zero issues over almost 300miles I drove it, including a long run from London. Car drives really good and is comparable to 3.0 Petrol Lexus I had before.

[GiveMeABreak]

Stop Start has nothing to do with the DPF.
Stop Start won't work if the prerequisite conditions are not met, which is most likely in your case to be poor battery health, given that it is not run regularly, so is gradually discharging. If the battery charge is anything under 80% then start stop won't operate.

The other thing is that if you are not running the car regularly and when you do use it, if the trips are short, then the vehicle is not going to get up to operating temperature. The exhaust gasses need to be at least 450°C in order for assisted regeneration to kick in and then the cycle needs to have enough time to complete.

If the cycle is interrupted, then the filter is never going to get a chance to regenerate.

You may need to take it on a good run of at least 20-30 minutes at a minimum of 40 mph (and I'd suggest you keep it in 4th or 5th to give the engine a chance to get to temperature more quickly.

[vileorange]

@GiveMeABreak If its not too much trouble can I please have a picture of an exhaust assembly from Citroen Diagnostics?
Am I right to assume that there is a Catalytic converter coming from the manifold then some pipe with urea injector and then a DPF as a separate unit?
My vin code is VF7**************[VIN obfuscated, can be read by forum staff]

[GiveMeABreak]

@vileorange:

If you need an original, genuine part number or part diagram, and can't already find the info you need on the Forum, we do ask for a membership upgrade for official parts data as we are in turn charged for this. It will cover you for future part number requests for up to 2 years, so excellent value.

If interested, links are below, we already have your VIN above.

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[vileorange]

Hello Everyone.
Just to wrap it up:
When the Fap pressure is unreasonably high, but the car drives OK (there could be an error and there could be no errors) it means that the deferential preassure sensor is:
1)Defective
2) Unplugged
3) Broken wires/corossion

In my case the sensor was unplugged and after plugging it in everything went back to normal. Preassure is perfect and filter in in perfect working condition.