Risk of dpf clogging, no check engine/dpf light, P1442 and P2566

[Cisco]

Hoping someone can help with issues regarding dpf/exhaust additive/who knows what on my 2014 Peugeot Express with the 2 l hdi diesel engine (well, it's a Toyota Proace but the platform is identical).
Symptoms I have:

- "risk of dpf clogging" and "engine fault: repair needed" warning messages on the display to the right, along with the red triangle warning light on the dash but no check engine or dpf light
- code P1442, permanent (additive system: adding impossible or additive level fault)
- code P2566, intermittent (turbo position repeat signal valve blocked when engine switched off)
- May or may not be related to the current issue, but I had some instances of a vacuum leak during acceleration, throwing the same p2566 code, with a brief hissing sound and loss of power; I had been planning to try and fix that by replacing the turbo actuator solenoid but haven't done that yet
- I checked manually that the additive tank is indeed full by unbolting it and sloshing it around.
- The warning light came on just after filling up the diesel tank. Since then it's been driving slower - it almost feels like the turbo is not kicking in at all.
- According to my scanner, an Autel maxidas ds708, the dpf soot loading is at 94%, 310 km since last regen, and I have 1.2 l of eolys additive out of the 1.6 l of a full tank. The pressure before and after the dpf is a few millibars, always below 10 even when revving in neutral. I tried a forced regen but nothing happened. The estimated life left on the dpf is 11000 km. The dpf temperature sensor reads realistic values, under 100 degrees with the engine off, between 100 and 200 when driving.

At this point, I'd appreciate it if someone could help me figure out what steps to take next to troubleshoot better. I'm thinking maybe some sensor went bad in the dpf, or perhaps the additive pump is broken? Or maybe the dpf is just nearing the end of it's life and the van is just warning me? Is it in fact the turbo?
I wonder if I should just get my hands on the proper psa diagbox to have more detailed and reliable readings.

Thanks to everyone - it's my first time posting, but going through other discussions on this forum has helped me out a lot in the past. I am happy to share more details if it helps but I didn't want to make this post too long

[mickthemaverick]

My course of action in this situation would be to remove the dpf and clean it manually, many videos on Youtube on how to do that, then reset the codes, refit the dpf and see what happens. Minimal cost and either a cure or one possibility eliminated. Personally I clean DPFs by 30 mins soak in brick acid followed by forward and backward flushing with a low pressure hose until clear water comes out both ends. Then dry thoroughly with a hot air tool and refit.

[Huskyxantia]

My experience of this and the repeated warning.
Everything I mention can be found in videos on YouTube, things to check and test.

Glow plugs for ohm resistance
All looms from glow plugs and 02 sensors
Check 02 sensors of ohm resistance
Check the engine bay fuses 30amp ones
Clean if they are grubby..change if blown
There's sprays that goes into the dpf via the top removal of the 02 sensor , as I say youtube covers all of these just search how to clean or Check then what ever your working on

[Cisco]

Thanks to both of you. I would have hoped that, if the issue is a clogged dpf, I would have gotten some more specific codes... but I guess it can't hurt to clean it at this point. I was hoping to avoid this as the pressure difference at the filter wasn't that bad after all. Anyway, I will check the things noted by Husky first

[Huskyxantia]

The dpf sensor is fairly cheap on ebay sometimes these break down , pipe work can suffer splits even tiny ones can give false positives too

[Cisco]

Nice. Is there any chance some of you knows precisely what triggers code P1442?

As soon as I have a bit of time, I'll look into the various sensors too to see if they are reading incorrect values. It would be helpful to know what resistance the sensors should be: do you know a good resource to look it up? I only know the additive pump should be around 20 ohm but don't know the dpf pressure sensors, temperature sensors and o2 sensors.

Many thanks, btw: you are really helping me out!

[mickthemaverick]

Have a read through here, it may give you an idea or two, https://www.engine-codes.com/p1442.html

[Huskyxantia]

Short circuit to positive, check the harness of it they can break in the little connector plugs, road dirt water grit and so on, possible fuse too