good morning ,

Today we are writing some notes on the problems of clogged FAP in FCA Group cars.

In particular, we look at what to do when the car does not perform and the diagnosis in the engine ecu shows the following error codes:

• P2452 - Differential pressure sensor
• P2454 - Differential pressure sensor
• P1206 - 1 DPF clogging level
• P2002 - 2 DPF clogging level

Error P2452 : The cause of the fault is electrical; before replacing the differential sensor, check the wiring and connections for short circuits, open circuits and loose contacts.

Error P2454 : If the vehicle has travelled less than 1000 km, the cause of the fault could be a build-up of water/moisture in the exhaust system due to repeated short journeys; perform a forced regeneration. If the vehicle has travelled more than 1000 km perform a forced regeneration.

Error P1206 and 2002 : These errors occur when the vehicle makes short journeys with continuous switching on and off, not allowing the engine to reach thermal regulation.

Depending on the distance travelled and the error present, proceed as described below:

• If the vehicle has travelled less than 1,000 km, the cause of the fault could be a build-up of water/moisture in the exhaust system due to repeated short journeys; perform a forced regeneration.
• If the vehicle has travelled more than 1000 km and error P1206 is present, perform a forced regeneration.
• If the vehicle has travelled more than 1000 km and error P2002 is present, DO NOT regenerate, and replace the DPF.

However, it is important to consider that the parameter - Particulate Filter Clogging - is a fictitious calculation performed by the engine control unit. If the engine control unit detects an error in this calculation, it will cause the DPF system to malfunction and the MIL warning light to come on and the P1206 error to be generated.

A second important consideration is the following in the case of use "NORMAL of the vehicle, i.e. when many kilometres a day are travelled on state roads, motorways, without stopping. In these cases, the causes of incorrect functioning of the FAP system are to be sought in other various origins:

• 1 - Incorrect functioning of engine thermostat .Incorrect functioning of the thermostat causes the particulate accumulated in the DPF to be miscalculated.Check that the engine water temperature is always > 85C.Change thermostat.
• 2 - Incorrect reading of the air flow through the air flow meter . In this case, check the actual measured air mass value.
• 3 - Incorrect Injector Operation . In this case, check the Injection Timing Correction Factor (between -2 and +2 mm3/injet with engine at idle and steady state)
• 4 - Presence of oil in the suction circuit.Check for the presence of oil in the suction circuit, checking the presence of oil in all pipes from the compressor inlet to the suction manifold inlet.
• 5 - Turbocharger problems check presence of oil at compressor outlet, analysis of the condition of the pipes and intercooler, check of the difference between target and measured pressure,acceleration response delay,failure to reach max. boost pressure
• 6 - EGR valve problems.Check for blockage, valve and manifold clogging, valve and wiring electrical problems. 
• 7 - Condensation Check whether water (condensation) has accumulated in the DPF filter. This happens on new cars with low mileage and which have not yet regenerated. This causes a false reading of the differential pressure sensor (high pressure - clogged filter - error P1206). The engine control unit switches on the Malfunction Indicator Light MIL.
• 8 - Oil leakage from valve guides.Check for possible oil leakage from one or more valve guides, which generates an uncalculated PM percentage.Check for oil fouling in the combustion chamber (piston top and injectors) and not in the intake.
• 9 -Driving behaviour . In such cases, check how the car is being driven. In particular, check whether the customer carries out the required maintenance. Good reading to all and best regards . Antonio