Emissions control: EGR, DPF, catalytic converter and AdBlueGeneric OBD-II codeUrgency: Garage soon
Code P242F: particulate filter (DPF) with excess ash
P242F means: diesel particulate filter restriction due to ash accumulation.[1][2] The ECU continuously calculates the ash accumulated in the diesel particulate filter (DPF) using a model that combines the accumulated exhaust gas flow, the differential pressure across the filter, the exhaust temperature and the kilometres driven since the filter was last cleaned or replaced. P242F is logged when the calculated ash reaches the maximum calibrated by the manufacturer.[1]
What code P242F means
The ECU continuously calculates the ash accumulated in the diesel particulate filter (DPF) using a model that combines the accumulated exhaust gas flow, the differential pressure across the filter, the exhaust temperature and the kilometres driven since the filter was last cleaned or replaced. P242F is logged when the calculated ash reaches the maximum calibrated by the manufacturer.[1]
Ash is not soot. It is the incombustible residue left when the filter burns off soot in a regeneration, and it comes mainly from oil additives, from the oil the engine consumes and from trace metals in the fuel. Unlike soot, it is not removed by a regeneration: it builds up and, when the filter fills with ash, it has to be cleaned or replaced.[1][3][4]
It is a generic OBD-II code (it starts with P2), with the same definition on any make. On VW Group cars, Ross-Tech describes it more generally as "Diesel Particulate Filter (Bank 1): Restricted/Clogged" (blocked filter) and recommends checking the filter load and carrying out a service regeneration; its notes refer to the VW Crafter with the 2.5 CR-TDI engine.[5][6]
Original definition (SAE J2012): Diesel Particulate Filter Restriction - Ash Accumulation[1][2]
Causes of P242F
From most to least likely, according to the sources.
- 1Ash accumulated through use: the filter has reached the end of its cleaning interval or of its service life. Many manufacturers set a maintenance schedule for removing the ash and, if the car is near that mileage, it is the first suspect.[1][2][3][4]
- 2More ash than normal because of an engine that consumes oil or excessive use of engine or fuel additives.[1][2]
- 3Faulty filter pressure sensor, with blocked or broken sensing pipes or an open or short-circuited electrical circuit, giving a wrong reading.[2][7]
- 4Ineffective regenerations, for example because of short journeys. Ross-Tech mentions, for VW Crafters used mostly on short runs, a specific software for that use.[2][5]
Symptoms
- Particulate filter warning light on the instrument cluster.[2]DPF warning light: faults that cause it
- Engine warning light on.[5]Engine warning light: faults that cause it
- Loss of power.[2]Less power: faults that cause it
- If you keep driving, the filter restricts the flow of gases more and more and the car may go into limp mode, with limited power.[4][7]Limp mode: faults that cause it
- Regenerations, both passive and active, that fail again and again.[2]
- Strong smell of diesel and excessive smoke.[2]
How to diagnose P242F
In order: from the most likely and cheapest to check to the most expensive.
- 1Read the codes and the freeze-frame data, and note them down: they will help you if the code is intermittent. Check the wiring and connectors of the pressure sensor, especially where they pass close to hot exhaust parts or sharp edges.[2]
- 2Check how many kilometres the filter has done since it was last cleaned or replaced and compare that with the ash-removal interval recommended by the manufacturer. Also ask whether additives have been used in excess or whether regenerations have been ignored.[1][2]
- 3With the diagnostic tool, look at the filter load and the other engine codes. On VW Group cars, the diagnostics also let you see the filter's ash value and the pressure sensor offset.[5][8]
- 4If the code returns straight away, test the pressure sensor with a multimeter to the manufacturer's specifications; if it is correct, check that the sensing pipes are not blocked or broken (when replacing them, use heat-resistant silicone tubes) and check the electrical circuit.[2]
- 5Check the ECU software version and the filter part number. On VW Crafter 2.5 CR-TDI models there are several generations of filter, and using the software from another generation damages the filter.[5]
- 6If the sensor, pipes and circuit are fine and the calculated ash is high, a regeneration will not solve it: the filter has to be cleaned at a specialist workshop or replaced.[2][3][4]
Can I keep driving with P242F?
Garage soon
The sources do not talk about immediate danger, but they do describe a filter that has reached its limit. PartsAvatar says the solution is to replace the filter, HELLA that it must be cleaned or replaced when it fills with ash, and Wikipedia that accumulated ash increases the restriction and can end up blocking the filter, with loss of power or limp mode. RACE advises against driving in limp mode because it increases exhaust pressure and temperature and can damage other components.[2][3][4][7]
Documented faults related to P242F
Known faults of specific engines and cars, with their repair cost, the affected years and their sources.
Particulate filter (DPF/FAP): the most serious faults by engine and car
- High severityFrequency: Very frequentOM651EGR and particulate filter clogging, and emissions software updatesThe particulate filter and EGR clog up with short journeys, as on any diesel with these systems. In addition, Germany's KBA required software updates on several models with this engine between 2018 and 2021 because of a function that reduced EGR outside a temperature range.Repair (garage): €800–€2,500
- High severityFrequency: Common1.3 MultijetIncomplete particulate filter regenerations and oil dilutionIn heavy urban use, with short journeys that do not let the particulate filter regeneration finish, unburnt diesel passes into the sump and dilutes the oil; the level can rise on the dipstick and the oil loses its ability to lubricate. Repeated many times, it speeds up engine wear.
- High severityFrequency: Common2.0 HDiDPF clogging on additive-type systems (Eolys/cerine)The additive-type diesel particulate filter (DPF) of the 2.0 HDi clogs relatively easily on short journeys, especially on the 107/110 and 136-140 hp versions. The anti-pollution warning light comes on and, if ignored, the car loses power and may end up needing a new DPF.
- High severityFrequency: Common1.6 and 2.0 MultiJet IISaturated diesel particulate filter (DPF) from incomplete regenerationsIn urban use with short journeys, the particulate filter does not manage to complete its regeneration and becomes saturated; garages recommend a weekly motorway run to avoid it. The filter itself is among the weak points flagged in the 1.6 and 2.0 MultiJet II after a certain mileage.
Oil consumption: the most serious faults by engine and car
- Critical severityFrequency: Very frequent2.0/2.2 D-4DWarped cylinder head gasket and oil consumption on the 2.2 D-4DYes: the 2.2-litre block (2AD-FTV and 2AD-FHV D-CAT) has numerous documented cases of warped cylinder head gaskets and oil consumption or dilution in the Avensis, RAV4, Auris, Corolla Verso and Verso, with repairs that sometimes require replacing the engine.Appears at around 40,000 km
- Critical severityFrequency: Common1.2 and 1.4 TSIPiston breakage and oil consumption in the 1.4 TSI twinchargerThe 1.4 TSI twincharger (turbo and supercharger) built up to 2012 can crack the pistons between the rings, with oil consumption, misfires and loss of compression. Volkswagen strengthened the pistons and rings on the 2012 CTHD engines.
- Critical severityFrequency: Common1.2 TCeExcessive oil consumption and engine failure1.2 TCe and 1.2 DIG-T engines built from 2012 to mid-2016 can burn more than 1 litre of oil per 1,000 km because the piston rings do not seal properly; carbon damages the valves and the engine can fail. There was no recall: the dealer network reprograms and replaces rings or the engine.Repair: €5,000–€10,000
- Critical severityFrequency: Common1.33 Dual VVT-iExcessive oil consumption from piston wearYes: 1.33 Dual VVT-i (1NR-FE) units built before 2013 can use far more oil than normal because of a factory defect in the pistons, acknowledged by Toyota in a technical bulletin. In the most serious cases it ends in engine replacement. Toyota corrected it with revised parts from 2013.Appears at around 130,000 km
Engine sensors: the most serious faults by engine and car
- High severityFrequency: Occasional2.0 DTI and 2.2 DTIVP44 injection pump and air mass meter failureGerman Wikipedia documents recurring failures of the Bosch VP44 injection pump and the air mass meter in the early years of this engine. An owner testimony for this engine describes the pump being replaced at 192,500 km, at a cost the owner calls «prohibitive».
- Medium severityFrequency: Common2.0 TDIClogged particulate filter or faulty pressure sensorThe 2.0 TDI's particulate filter clogs if the car mostly makes short journeys, because it never gets to regenerate; sometimes the fault is just the differential pressure sensor. Cleaning it costs around €200 and replacing it, €800 to €3,000.Repair (garage): €800–€3,000
- Medium severityFrequency: Common1.4 and 1.6 8vCrankshaft position sensor failure (TDC sensor)The crankshaft position sensor (capteur PMH, or TDC sensor) appears repeatedly in the reliability sources for the Clio II, the Kangoo I and the Dacia Logan I with this engine, with hard cold starting or stalling as the main symptoms. It is a cheap part, but the failure can leave you stranded.
- Medium severityFrequency: Common1.4 and 1.6 16vCrankshaft position sensor failureThe crankshaft position sensor (capteur PMH) appears repeatedly in the reliability sources for almost every generation with this engine, with hard cold starting, stalling or the car cutting out unexpectedly. It is a cheap part, but the failure can leave you stranded.
P242F by make
Documented faults that can trigger P242F in each make's engines and cars.
- P242F on Seat11
- P242F on Škoda11
- P242F on Volkswagen11
- P242F on Toyota10
- P242F on Opel9
- P242F on Citroën8
- P242F on Fiat8
- P242F on Mazda8
- P242F on Peugeot8
- P242F on Alfa Romeo7
- P242F on Audi7
- P242F on Nissan7
- P242F on BMW6
- P242F on Renault6
- P242F on Volvo6
- P242F on DS5
- P242F on Ford5
- P242F on MINI5
- P242F on Dacia4
- P242F on Hyundai4
- P242F on Jeep4
- P242F on Kia4
- P242F on Lancia4
Frequently asked questions
What is the difference between P242F and P2463?
Both indicate a blocked particulate filter, but for different reasons. P2463 is caused by soot, which is removed by burning it off in a regeneration. P242F is caused by ash, the incombustible residue left after soot is burned and which a regeneration does not remove: the filter has to be cleaned or replaced. P2002, by contrast, does not measure blockage but filtering efficiency.[1][3][9][10]
Can P242F be cleared with a regeneration?
If the origin really is ash, no: the regeneration burns the soot, but the ash stays in the filter, and it has to be cleaned at a specialist workshop or replaced. There is an apparent exception: on VW Group cars, Ross-Tech describes P242F as a blocked filter and recommends checking the load and carrying out a service regeneration, so it is worth having the garage check the real filter load first.[3][4][5]
Why does ash build up in the filter?
Ash comes from oil additives, from the oil the engine consumes and from trace metals in the fuel, and builds up with the kilometres. Excessive use of engine or fuel additives can speed up the process.[1][2]
Can I drive with P242F?
You can normally get to a garage, but you should not put it off: a filter full of ash restricts the flow of gases, can reduce power and, if the car goes into limp mode, RACE advises against driving like that because it increases exhaust pressure and temperature.[4][7]
How often does the ash in the filter need to be cleaned?
There is no single interval: most modern diesel manufacturers recommend a maintenance schedule for removing the ash, and it varies by engine. Check your car's maintenance schedule.[2]
Will I pass the MOT with code P242F?
If the code has switched on the engine warning light, no: with that light on, the inspection records a serious defect, and on Euro 5 and Euro 6 cars the ITV (Spain's roadworthiness inspection, similar to the MOT) also reads the OBD diagnostic system. Repair the fault before you go; clearing the code just before the inspection does not help either, because it counts as a serious defect.[11]
Not sure what is wrong with your car? Describe what you notice in the symptom diagnosis or see all fault codes.
Sources
Every fact on this page links to its source. If you find an error, let us know.
- P242F Fault Code Definition & Info | TaTThe Automotive Technician (TaT) · Technical documentation · consulted 2 October 2026
- PartsAvatar.ca - P242F OBD II Error Code SolutionPartsAvatar · Technical documentation · published 17 May 2023 · consulted 2 October 2026
- El sistema DPF (Filtro de Partículas Diésel) - Boletín InformativoHELLA · Manufacturer · published 2015 · consulted 2 October 2026 · in Spanish
- Diesel particulate filterWikipedia · Other source · consulted 2 October 2026
- P242F/009263 - Diesel Particulate Filter (Bank 1): Restricted/CloggedRoss-Tech · Technical documentation · consulted 2 October 2026
- On-board diagnosticsWikipedia · Other source · consulted 2 October 2026
- ¿Qué es el sistema antipolución del coche y qué averías puede sufrir?RACE · Motoring press · published 25 September 2026 · consulted 2 October 2026 · in Spanish
- 18885/P2453/009299 - Diesel Particle Filter Differential Pressure Sensor: Implausible SignalRoss-Tech · Technical documentation · consulted 2 October 2026
- P2463 Fault Code Definition & Info | TaTThe Automotive Technician (TaT) · Technical documentation · consulted 2 October 2026
- P2002 - Particulate Trap Efficiency Below Threshold - Bank 1 | TaTThe Automotive Technician (TaT) · Technical documentation · consulted 2 October 2026
- Desmontando mitos: ¿puede pasar mi coche la ITV con el testigo de «avería motor» encendido?Diariomotor · Motoring press · published 8 March 2021 · consulted 2 October 2026 · in Spanish