C3 Picasso 1.6hdi MOT Emissions fail....

[GiveMeABreak]

To clarify this - not necessarily!

Yes - under normal circumstances where the pouch has been replaced or the tank has been filled up and the additive counter in the Engine ECU has been reset.
No - If the additive pouch / tank has not been replaced, but the additive ECU has been reset. Some unscrupulous people may reset the additive counter without replacing the additive when selling on a car to get rid of the warning! The ECU thinks there is now a full supply of additive, so the warning about the additive level being low won't come on. The next warning you will get will be about the 'Risk of Clogging' of the particle filter, as without the additive fluid, the exhaust temperatures need to be about a 100 °C higher to burn the particulate matter off and this will only happen on longer, more sustained journeys of course.

As I mentioned, the additive tank system has no physical measurement of the level of fluid remaining, it is estimated. It therefore relies on the additive ECU being reset. If this is not done, the ECU has no way of knowing the additive or pouch has been replenished.

[sadssandiford]

Cheers Marc but where will I get the risk of clogging message?
What message would I get with a blocking dpf/dpf differential pressure disparity?

[GiveMeABreak]

• For low additive, the SERVICE warning lamp will remain on and will be accompanied by a message on the multi-function screen.
• For the start of particle filter saturation, the SERVICE light will come on temporarily along with an associated message on the multi-function screen. As soon as the traffic conditions permit, regenerate the filter by driving at a speed of at least 40 mph until the warning lamp goes off.

The pressure sensors are used by the engine ECU to determine levels of blockage and trigger regeneration / warnings.

[sadssandiford]

When the car is doing a regeneration does the car give any indications?
Only reason I ask is as I've never seen any messages about it!
Also, can you force the car to do a regeneration??

[GiveMeABreak]

No, the process is automatic and happens without you being aware - at anything from about every 200 to 450+ miles depending on driving habits and journeys.

If you happen to have the windows open and are stopped when regeneration is happening, you may detect a slight noise in the engine, but normally nothing else.

Yes, you can force a regeneration, but requires suitable Diagnostic equipment like Diagbox to initiate the process. It is not recommended unless absolutely necessary, due to the extreme heat generated and the toll it takes on surrounding components as the car is stationary. It has to be done away from anything flammable and not on tarmac or grass for obvious reasons of fire / burning.

[sadssandiford]

Hi all, got the engine carbon cleaned yesterday, which was very informative! The guy took me through everything, including showing me past mot emission results, both pre and post carbon clean.
Anyway, the clean took 60 mins of idling the car while hydrogen gas at a measured rate was fed into the intake.
Long story short, took the car back for MOT retest and it's passed.....!
The plate limit for my car is 0.5 and the measured results were 0.64, 0.61, 0.15, 0.2, 0.15 and gave me an average reading of about 0.3, so a pass!
I also put 10L of Shell VPower Diesel into a tank with about 15L of Tesco diesel, so that may of helped.
All in all, its passed so another year's motoring....

[GiveMeABreak]

Well done!

[mickthemaverick]

All's well that ..... etc. Well done!!

[sadssandiford]

All thanks to the members on here, again many thanks everyone!

[Sar123]

My friend had similar issues on her 1.6HDi C4 Picasso and I removed the dpf, soaked it in brick acid for 90 minutes and then back flushed, forward flushed and back flushed again. Re-assembled and no trouble ever since. The only thing I would advise is to protect the radiator matrix while you are working. it is vulnerable to a slip, at least it was on the C4 Picasso!! The whole job cost her £12 for the brick acid and me £85 for a replacement radiator!!

Just out of interest where did you buy the brick acid from? I might have to do what you did to my c4

[mickthemaverick]

I got it from Wickes, you should be able to find it in any builder's merchant. It is basically diluted Hydrochloric Acid which is sold in various forms but I find the brick acid the easiest to source!