Subaru bóxer (gasolina EJ and FB and diésel EE20)Particulate filter (DPF/FAP)
Clogged particulate filter on the EE20 diesel on the Subaru bóxer
Why this rating?
Medium severity: It can leave you stranded or get worse if ignored, without destroying the engine.
Frequency common: Gebrauchtwagenberater says the filter clogs "frequently" on cars up to the end of 2010; AUTO BILD lists it among the problems of the diesel XV I, where 32% of reader-owners of the diesel report engine problems (without distinguishing which), and the Polish article says the filter started to cause problems. There is no statistic specific to this fault.[1][2][3]
Symptoms
- AUTO BILD lists a rising engine oil level alongside clogged particulate filters; it also records owners without that problem.[2]Oil level rises: other faults that cause it · Garage soon
Why it happens
The sources describe the filter clogging but do not explain its cause. The Polish article clarifies the design: the first Legacy and Outback had an open filter (similar to a catalytic converter) for the first two model years and then switched to dry filters, which burn off the soot by injecting extra fuel.[1][3]
If it is not repaired: AUTO BILD associates clogged filters with a rising oil level; the sources do not explain that relationship or cite other consequences.[2]
Affected cars and years
Gebrauchtwagenberater places it mainly on diesel Imprezas up to the end of 2010; AUTO BILD cites it for the XV I, whose diesel has been sold since late 2011, so it is not limited to the early years.[1][2]
| Version | Years | Codes |
|---|---|---|
| 2.0 D 147-150 hp Euro 4 (EE20, 2008-2010) | 2008–2010 | EE20 |
| 2.0 D 147-150 hp Euro 5 (EE20, 2010-2015) | 2010–2015 | EE20 |
| 2.0 D 147-150 hp Euro 6 (EE20, 2015-2018) | 2015–2018 | EE20 |
Models fitted with the affected versions
Subaru
- Subaru Forester III2008–2013
- Subaru Forester IV2012–2018
- Subaru XV I2011–2017
- Subaru Outback IV2009–2014
- Subaru Outback V2015–2021
- Subaru Impreza III2007–2011
- Subaru Legacy V2009–2014
How much it costs to repair
Includes: Cleaning or replacement of the EE20 particulate filter.[1]
No open source publishes the price of this repair.
Prices in Spain, including VAT. A workshop hour costs on average €38–66 at independent garages and €77–134 at dealerships in Spain, depending on the region and the brand. How we calculate costs
How to check for it before buying a used car
Parts needed
The part or kit that fixes this fault, according to the sources.
- Buy part at Autodoc (affiliate link, opens in a new tab)
EE20 diesel particulate filter (DPF)[4]
Traps the soot from the exhaust; on the Euro 4 EE20 it sits next to the turbo to make use of the heat, according to English Wikipedia.
Affiliate links to Autodoc: if you buy, MotorFiable may receive a commission at no cost to you. Check compatibility using the registration number or the VIN before ordering. More information
How to prevent it
- Avoid limiting use to short urban trips, which make filter regeneration difficult (general advice, not from the cited sources).
Recalls, campaigns and claims
As of 9 October 2026, we have no record of recalls, campaigns or extended manufacturer warranties for this fault. Check with an official dealer using the chassis (VIN) number: they will tell you whether the car has any outstanding campaign.
What owners say
Frequently asked questions
Which years of the Subaru diesel have the most particulate filter problems?
Gebrauchtwagenberater places them mainly on cars built up to the end of 2010; AUTO BILD still cites it on the diesel XV I, which was sold from 2011.[1][2]
Did the first diesel Legacy and Outback have a different type of filter?
According to Autoblog's Polish article, for the first two model years they had an open filter, similar to a catalytic converter, and then dry filters that burn off the soot by injecting extra fuel.[3]
Is it normal for the oil level to rise in a diesel Subaru?
AUTO BILD lists it among the problems of the diesel XV I, although it also cites owners without that problem. If the level rises between services, have it diagnosed at a garage; the sources do not explain the cause.[2]
What can you do now?
We will put you in touch with a partner only if you authorise it in the form.
Other Subaru bóxer faults
- Critical severityFrequency: CommonLubricationBearing wear and crankshaft failure on the EE20 dieselOn the first EE20 boxer diesels (Legacy and Outback built from autumn 2007 to February 2009; Impreza 2007-2009) the crankshaft bearings could fail and break the crankshaft, destroying the engine. AUTO BILD cites two causes: silicone in the sump and bearings with incorrect clearance.Appears at around 65,000 km
- High severityFrequency: OccasionalCylinder head and blockDamaged cylinder head gasket on the EJ petrol enginesDamaged cylinder head gaskets are cited on the EJ petrols (2.0 and 2.5), especially on older cars; Wikipedia records frequent failures of the single-layer gasket on the EJ251, and SlashGear places Subaru's switch to multi-layer steel gaskets around 2010.
- Medium severityFrequency: OccasionalInjectionImprecise injectors and sooty EGR valve on the EE20 dieselThe EE20's Denso injectors can work imprecisely and produce a knocking noise, and soot in the injectors and EGR valve can lead to expensive repairs; AUTO BILD cites 500-800 euros per injector in Germany.
- Medium severityFrequency: OccasionalIgnitionShort-circuiting ignition coils on the Forester, XV and Impreza (2016-2019)Two British campaigns (2020 and 2021) affect 2,338 Forester, XV and Impreza cars built from September 2016 to October 2019: one reprograms the control unit because the coil stays powered after the engine is switched off, and the other replaces all the coils, which can short-circuit and leave the car unable to start.
- High severityFrequency: RareCylinder head and blockValve spring breakage on models built in 2013 and 2014In 2019 the DVSA recorded a recall for possible valve spring breakage on the Forester, Impreza, XV, Outback, Legacy and BRZ built in 2013 and 2014 (812 cars in the UK); the fix is to replace all the springs.
- Medium severityFrequency: RareTransmissionLeaking CVT gearbox oil cooler hose on the Legacy and Outback (2010)In 2010 the DVSA recorded a recall of 404 British Legacy and Outback cars for a CVT gearbox oil cooler hose that could break, causing loss of drive and oil on the road; a modified hose is fitted.
More faults with the particulate filter on other engines and cars
- 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.
- High severityFrequency: Common2.0 Ingenium diéselFuel dilution of the oil linked to particulate filter regenerationsYes: on short trips and in urban use, the Ingenium diesel's particulate filter does not always complete regeneration, and some of the diesel injected to burn off the soot ends up mixing with the engine oil, which reduces its ability to lubricate.
- High severityFrequency: CommonMZR-CDOil dilution from leaking injector seals and DPF regenerationsOn the 2.0 and 2.2 MZR-CD, injector seals that age badly and incomplete particulate filter regenerations on short journeys can let unburnt diesel into the sump, diluting the oil and leaving the engine with less lubrication.
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Sources
Every fact on this page links to its source. If you find an error, let us know.
- Subaru Impreza III – Bekannte Probleme & SchwachstellenGebrauchtwagenberater · Motoring press · published 6 September 2023 · consulted 9 October 2026 · in German
- Subaru XV I im Gebrauchtwagen-Test: «Vorsicht vor dem Boxer-Diesel!»AUTO BILD · Motoring press · published 17 December 2019 · consulted 9 October 2026 · in German
- Jak to działa: silnik Boxer Diesel w samochodach SubaruAutoblog (Spider's Web) · Motoring press · published 29 August 2018 · consulted 9 October 2026 · in another language
- Subaru EE engine (diesel), en «List of Subaru engines»Wikipedia (en) · Other source · consulted 9 October 2026