Working on particulate filter systems is now a daily practice for workshops, especially on modern diesel engines. Clogged filters, faulty sensors, and incomplete regenerations are common problems that require technical expertise and the proper use of electronic diagnostics.
For PSA Group engines (Peugeot and Citroën), the system has a unique feature: the use of a specific additive (cerin), which requires additional management and resetting.
PSA FAP System: More Complex Management
Unlike other systems, the PSA DPF uses an additive that facilitates filter regeneration by lowering the combustion temperature of the particulate matter.
This involves:
- Need to top up the additive (cerin);
- Constant level monitoring via the control unit;
- Reset and initialization procedures after each intervention.
These diagnostic operations may not be immediate and, if not performed correctly, may prevent the definitive resolution of the problem.
Case study: clogged DPF and insufficient additive level
One of the most common situations concerns the 1.6 HDi engine, where a clogged particulate filter and insufficient additive level can be found simultaneously.
The following fault codes may be present in the ECU:
- P1454 – indicates excessive additive addition, often due to difficult regenerations that have worsened the filter clogging.
- P15B3 – additive level below the minimum threshold.
Intervento corretto: non solo sostituzione
Resolving the problem requires a comprehensive approach:
- Cleaning the DPF (or replacement in the most severe cases);
- Restoring the cerine level;
- Resetting and initializing via diagnosis.
Simply replacing or topping up without performing the electronic procedures almost always leads to the errors reappearing.
Topping up the additive: what you need to know
In PSA engines, the additive reservoir consists of an internal bag inserted into a plastic container.
After filling, however, the system does not automatically recognize the new level, requiring diagnostic intervention.
Reset and initialization procedure
To complete the intervention correctly, it is necessary to operate on the control unit using a diagnostic tool:
Update of interventions performed
In the Settings / Programming menu, you must:
- Report the cleaning or replacement of the DPF;
- Record the additive topping up.
Initialize fuel consumption
Next, you must access the Learning menu and perform:
- Enter the estimated amount of cerine accumulated in the filter;
- The value must be consistent with the vehicle’s mileage (e.g. 110,000 km → 49 grams of cerine – value to be entered: 0049)
Why resetting is essential
If this procedure is not performed correctly:
- The P1454 code will not be clearable;
- The control unit will continue to consider the filter saturated;
- The particulate filter system will not function properly.
Only after a complete initialization will it be possible to clear the fault codes and restore proper system operation.
Conclusion
In PSA particulate filter systems, the electronic component is as crucial as the mechanical one.
Proper repairs involve more than simply cleaning/replacing the filter or topping up the additive; they require a precise and complete diagnostic procedure, without which the problem cannot be considered resolved.