Depollution Fault 1.6 HDI GP

[Delvey]

I had an issue with a depollution fault on a 1.6 HDI C4 Grand Picasso. A new exhaust pressure sensor has solved this issue after checking diagbox to see the issue. I then ran a forced regeneration on the motorway last night as the level of soot read 98%, but again came with the depollution message. The regen seemed to be going fine until depollution fault again which stopped the regen process. This only occurs during motorway driving (speeds over 60mph)

I have read this could be caused by an actuator, is there a way to check in diagbox? Or could it be the turbo pressure solenoid needs replacing?
As for the soot level, it is now 5% and stayed like that all the way home. Could this be a false reading?

[GiveMeABreak]

Hi and welcome.

So from your screenshot, you have the BOSCH EDC16C34 Injection System.#

Any issue in the Air / Fuel Circuit will prevent or interrupt the regeneration process.

Fault P0234 has the following information: (Click to Zoom Table)

So check out the 'Suspect Areas' at the bottom and work you way through.

[Delvey]

Thanks for the information. Is the turbocharging pressure sensor the MAP? Is there anyway to diagnose a faulty sensor using diagbox? Same question with the position sensor, Is this the actuator? MAP sensor is not expensive but if not faulty do not want to replace
Interesting that driving with the accelerator fully depressed for 5 minutes solves the issue, will try that next time it happens
A faulty turbocharger does not seem like the issue, I know these need regular oil changes which it has had to prevent build up of carbon in the pipes.

[GiveMeABreak]

Here is where the main sensors are for reference:

(2) Water Temp Sensor (6) Engine Speed Sensor (7) Camshaft Position Sensor (8) Temp Sensors (GO + Support) (9) Air Intake Pressure Sensor (10) Mass Airflow Meter (11) Air Intake Temp Sensor (12) Diesel HP Sensor

Here are the Turbo unions for Ref:

(1) Vacuum Solenoid Valve (3) Vacuum Reserve (5, 6 & 7) Air Turbo Unions

[Delvey]

Thanks. Look like the Vacuum solenoid Valve is round the rear. I shall double check that first for any loose hoses/splits etc

[GiveMeABreak]

Good idea to start with the likely causes first and a split turbo hose can cause all sorts of rough running.

[Delvey]

Good idea to start with the likely causes first and a spit turbo hose can cause all sorts of rough running.

Will check that as well. Under non-motorway urban conditions the car is fine and throws up no error codes.

[Delvey]

Is this the correct page for monitoring turbo pressure?
Not had time to check any pipes etc however when I do want to ensure the correct parameters are being monitored

This is the car not stationary with me applying throttle. So the measured value is higher than the reference value even when not under any kind of load
Thanks in advanced

[Delvey]

Starting to hate the car now
Doing an oil/filter change today, and as you can see an air intake pipe is missing! It was there 2 weeks ago

And can I replace it with some standard rubber tubing? If so what is the diameter?
From the picture below, is the apart circled the turbo filter?


And to add more insult to injury, the fan for the radiator is no longer attached, seems to have broken from the mounting.

[Delvey]

Quick update, sorry for all the bothering
Diagbox is showing the below

So the position indicator is constantly 100%, even when driving. Could this be the issue? Would it be a faulty actuator or faulty sensor?
Also, the pipe to the right of the turbo I disconnected and it had no suction, is this correct?

[MikeT]

There is indeed a mismatch between turbo position reference (command) and position indicator (sensor).
If you can get someone to start the engine for you, you should observe the actuator arm being pulled down ~12mm.

[Delvey]

There is indeed a mismatch between turbo position reference (command) and position indicator (sensor).
If you can get someone to start the engine for you, you should observe the actuator arm being pulled down ~12mm.

Thanks. I am on holiday until next weekend but will try that when I return

[Delvey]

There is indeed a mismatch between turbo position reference (command) and position indicator (sensor).
If you can get someone to start the engine for you, you should observe the actuator arm being pulled down ~12mm.

Not replied for a while as been on holiday and started a new job
The actuator is moving on engine start. The car seems to behaving itself and not gone into limp mode recently. I need to plug it into diagbox to see the readings however
Anyone know the part number for the orange washer to the right of the turbo? Mine is in bad shape, is quite brittle and has various cracks in it

[RichardW]

Anyone know the part number for the orange washer to the right of the turbo? Mine is in bad shape, is quite brittle and has various cracks in it

If you mean the bit in the inlet hose to the turbo, then it's:

Part Number Description Quantity Price excl. VAT Price incl. VAT Total incl. VAT Selection
00001434C8 SLEEVE 1 15.72 GBP 18.86 GBP 18.86 GBP

Quite dear for a little piece of rubber

[Delvey]

Thats the one, thanks
A little cheaper on ebay, blood expensive like you said
https://www.ebay.co.uk/itm/Citroen-1-6- ... 2185509937