FAQ
TL;DR: 205 km average between last five DPF regenerations shows the filter is not yet blocked [Elektroda, willyvmm, post #16825645] “Sensor sees 0 mbar as if DPF isn’t there” [Elektroda, andrzej20001, post #16826789] Correct the cause—usually ash load or bad pressure reading—before damage spreads.
Why it matters: Ignoring the early warning doubles the risk of limp-mode and costly DPF replacement.
Quick Facts
• Peugeot/Citroën OEM pressure sensor 1618.Z9: 0–100 mbar range [Elektroda, willyvmm, post #16829592]
• Healthy idle pressure: 3–7 mbar; >200 mbar under load signals clogging [Elektroda, adam7009, post #16829266]
• Normal regeneration interval: 600–800 km highway driving [Elektroda, andrzej20001, post #16825692]
• Additive dose: ≈10 ml per refuel; ECU stores calculated quantity [Elektroda, willyvmm, post #16825645]
• DPF cleaning €100–€200; new filter €400–€600 [AutoExpress, 2022]
What triggers the “Risk of particle filter clogging” message?
The ECU compares estimated soot loading with recent regeneration distance and differential pressure. When predicted ash mass nears the filter limit or regeneration frequency drops below ≈300 km, it lights the warning even if back-pressure is still low [Elektroda, willyvmm, #16825645; #16826218].
Does the warning always mean the DPF is blocked?
No. In the thread the filter showed only 18 % filling and 40 mbar at 3 300 rpm, yet the message appeared. Short trips, interrupted regenerations or sensor errors can all raise perceived risk [Elektroda, willyvmm, #16825645; #16826299].
What differential pressure values are considered normal on the 1.6 HDi?
Expect 3–7 mbar at idle, 30–60 mbar at 3 000 rpm, and under 200 mbar at full load. Zero or constant high readings indicate sensor or hose faults [Elektroda, adam7009, post #16829266]
How far apart should regenerations occur in everyday driving?
Highway use stretches intervals to 600–800 km, while city stop-and-go can shorten them below 300 km. If intervals fall under 200 km, investigate soot causes [Elektroda, andrzej20001, post #16825692]
Can repeated short trips really trigger the warning?
Yes. Each aborted regeneration leaves extra soot. Five consecutive interruptions can raise calculated loading by 10 – 20 % and force an early alert [Elektroda, willyvmm, post #16826218]
How do I test the differential-pressure sensor?
- Disconnect both hoses and attach a hand vacuum/pressure pump.
- Compare live ECU value with an external manometer every 10 mbar.
- Replace the sensor or leaking hose if deviation exceeds ±5 mbar [Elektroda, zyganps, post #16828607]
Could a faulty sensor hose mimic a blocked or empty DPF?
Yes. A leak before the sensor shows negative or near-zero pressure; a leak after it shows constant positive pressure. Both force extra regenerations [Elektroda, willyvmm, post #16826685]
How much additive should remain, and does the car measure the tank level?
EDC16 stores a calculated volume; it may not have a physical float. Thread readings showed 900 ml in ECU memory versus 1 500 ml in the additive module, still acceptable above 500 ml [Elektroda, willyvmm, post #16826403]
When should I clean instead of replace the DPF?
If idle pressure stays below 7 mbar and soot load under 50 %, ultrasonic or chemical washing restores flow for €100–€200. Cracked substrates, melted monoliths, or >250 mbar readings need a new unit [Elektroda, ptr92, #16826618; AutoExpress, 2022].
How do I reset the ECU after cleaning or replacing the filter?
Use diagnostic software to log in to the additive ECU, choose “DPF replacement,” confirm VIN, and zero the soot-load counter. This takes under two minutes [Elektroda, ptr92, post #16826618]
What happens if the sensor reads 0 mbar at idle?
The ECU assumes the filter is missing, clamps EGR and increases post-injection. That raises fuel use by up to 8 % and triggers the risk message [Elektroda, andrzej20001, post #16826789]
Edge case: What if someone drilled the DPF core?
A punctured monolith drops pressure to nearly zero yet leaves the housing intact. The ECU enters regeneration loop, emission test fails instantly, and a fine of up to €2 000 applies in many EU states [“EU Type-Approval Rules”, 2021].
How can I perform a safe forced regeneration while stationary?
- Connect diagnostic tool, coolant ≥70 °C.
- Engage forced regeneration; hold 2 000 rpm until fan stops (~20 min).
- Check pressure drop; abort if it exceeds 250 mbar [Elektroda, Cysiek89, post #16826382]
![[1.6 HDI 187kkm FAP 109KM] - Risk of particle filter clogging: see handbook](https://obrazki.elektroda.pl/4402602600_1510920878.jpg "[1.6 HDI 187kkm FAP 109KM] - Risk of particle filter clogging: see handbook")
