DPF Clogging

[Steve Walsh]

I get quite a few '' Risk of particle filter clogging'' Messages pop up. Even after a motorway run in 5th gear to keep engine speed up.

Any advice going off the photos enclosed., I have cleared the faults numerous times and even tried a non gen pressure sensor, that one also caused a different fault to pop up so I changed it back.

VF7**************[VIN obfuscated, can be read by forum staff]

All advice very welcome

Steve

[GiveMeABreak]

Not sure what you mean by a non gen pressure sensor...

Do you mean the differential pressure sensor?

If so, it is essential these pipes ('c' & 'd') are not inverted.

"c" HI: Particle filter upstream information input (diameter 4,32 mm).
"d" REF: Particle filter downstream information input (diameter 4,32 mm).
"e" White marking.
"f" Electrical connector.
"g" Diaphragm.

Note the sensor range voltage to pressure is 0.5V to 5V. 0.5V (Engine Off) represents 0 Bar with 4.1V representing 0.9 Bar (filter clogged)

Regarding the particle filter - I'm not sure about those readings. It says that the distance travelled since the filter was replaced has been 100,000 KMs yet distance remaining before replacement is showing as 200,000 kms. Now for the 2.0 HDi for the particle filter should be checked at between 112,000 to 120,000 miles which is about 193,000 kms. So according to that you've done 100k and have another 200k to go which does not make sense as 300k is far too long for the life of a filter. So.... has the engine ECU wrongly been told the filter has been replaced when it hasn't to get rid of previous warnings?

The blockage doesn't seem too bad if that data is correct as referring to the figures I quoted above the scale is 0 to 900 mbars and you show 7 mbars....

Here's your fault descriptor:

Fault Code P1490: Particle emission filter differential pressure sensor: Particle filter overloaded. The number of regeneration requests aborted 2. The ECU changes to kilometric regenerations.

Conditions of disappearance of the fault: Driving for 5 minutes
Down-grade modes if fault present: Message on the multifunction display: Risk of particle filter clogging.

Symptoms: Jerking/stalling, Lack of power, Noise.
Suspect Areas: Pneumatic meter of the turbo air cooler by-pass, Particle filter, Particle filter differential pressure sensor, Particle filter upstream temperature sensor, Soft pouch of the particle filter additive reservoir, Additive pump, catalytic converter, Anti-return valve (Between the reservoir and the additive hose), Customer making very short journeys, Lack of additive in the reservoir

[Steve Walsh]

Hi Marc

I suspect your right about the ecu being told the DPF had been replaced, when it had not. I have had the car for 10 months, It had about 176000 km on when I got it and now has 194850 km
The DPF looks like original and is a one piece exhaust unit front to back.
When I started to get Fault code P1490. I bought a non genuine Differential Pressure Sensor, the Millibar readings where the same as original but after driving it, another fault code appeared, I cant remember the code but It said Diff. Press sensor voltage not correct, so I refitted the original.
I suspect I will have to change the DPF soon,
I am now wondering if the ECU has been told that the eolys was refilled and the job not done.
The car came from a private seller, But............Her brother has a small Citroen Garage here in France.. He obviously would have access to Lexia.

Thanks for the info

Steve

[GiveMeABreak]

So the exhaust is in 3 main parts:

Your catalytic Converter / DPF is A
The Particle Filter Pipe mid section is B
The Rear Box is C

First thing I would do is get the correct pressure sensor fitted - I wouldn't take chances with aftermarket possibly cheaper parts for this as the whole system depends on correct info being received.

The differential Pressure Sensor is item (1) below and that is part number: 1618Z9, priced at £91.52 inc. UK VAT from Citroen for a genuine part.

I've seen them used here in France from about 19.75 Euros:
https://eurofrance24.com/sensor-fap-966 ... 618z9.html

Additive: Unfortunately, the only way to determine the actual amount in the additive tank is to physically remove and empty the the additive tank and measure the fluid if you suspect the estimated reading to be incorrect. It does seem it is regenerating, but has 2 aborted attempts recorded (for whatever reason - this may just be interrupted for example).

If the engine ECU has been told the DPF has been replaced, it will also reset the amount of additive dumped into the filter and reset the values back to zero. Yours is currently reading 6 grammes.

Now I can tell you that on this engine (DW10BTED4) on the earlier MK II C5 that had a separate additive ECU (now undertaken by the engine ECU on the X7) the amount of Cerine (non-combustible components) dumped into the particle filter would be about 127 grammes for a 6 speed manual at 75,000 miles distance and 99 grammes for an automatic.

Those readings are for the DW10BTED4 (RHR-RHL) engines on the MK II, and you have the later RHF fitted on your X7, so even if we allow for the slightly different engine you can see something isn't quite right.

This could be a bit of skulduggery by an unscrupulous previous owner to tell it the DPF has been replaced to sell the car on, but I can't say that for sure, but the readings do not appear correct even if the filter was replaced as Cerine dumped into the filter is too low for 100,000 kms of travel.

[Steve Walsh]

Thanks for all that Marc, I have just ordered sensor from eurofrance24, I will fit that and take it from there, Fairly sure my exhaust system is 1 piece including DPF, Middle pipe and rear silencer.

Best regards

Steve

[GiveMeABreak]

I can assure you it is not one part Steve.

The particle filter is just one section as you can see here: the intermediate pipe connects to the right, and ditto for the rear box.

[Steve Walsh]

Hi Marc

Just been under the car and the exhaust system is definitely 1 piece, there is also Citroen Logo on rear silencer.. Looks like the picture you have labelled with the red a,b,c. But all in 1 piece with no joins.

Steve

[GiveMeABreak]

No, not possible, just a tight fit and you'll find the joins are probably covered with a collar that makes it look like one piece. It is designed so individual parts can be replaced, as it would be prohibitively expensive and probably against the EU regs to make one have to replace the entire system including the catalyst and DPF if you only need a rear box.

I can assure you that they are in 3 parts!

The collars are shown for the part above as item (22). Let me put it another way - you cannot get an all-in-one one piece replacement.

[GiveMeABreak]

And if you still need convincing:

The bi-conical connections are shown at (8). The joins are probably hidden by the heat shields or muck.

Reference	Designation	Engraving
(1)	pre-catalyst	TR PSA K433
(2)	Pressure take-off (Before )	-
(3)	catalytic converter (With hose)	TR PSA K403 (*)
(4)	Particle filter	TR PSA F014 (*)
(5)	Pressure take-off (Rear )	-
(6)	Middle piping	-
(7)	Exhaust rear silencer	PSA 4295
(8)	Bi-conical connections (66 mm diameter)	-

[Steve Walsh]

Well Marc, I will have to take your word for it, I trust everything you say regarding Citroens but I have been under the car with a torch and cant see any joints, it is very clean and nothing hidden. If I get chance tomorrow i will get it up on axle stands and have another look.

Thanks

Steve

[Steve Walsh]

Hi Marc
Just been back under my car, and the only conical joint with a clamp is the front pipe up behind the engine. It is different from the picture you put on.

I have just received my replacement Differential pressure sensor, so hoping that cures my problem

Steve

[GiveMeABreak]

Can't quite tell which area the last part is, but looks like a joined area to me - partially masked by the heat shield:

Best of luck with the repair.