P242F on Mercedes-Benz
Diesel Particulate Filter Restriction - Ash Accumulation (Bank 1)
P242F on Mercedes-Benz vehicles indicates diesel particulate filter restriction - ash accumulation (bank 1). Au7o has documented this code across 3 Mercedes-Benz models — most commonly on B-Class, GLS, V-Class. P242F is a generic diesel emissions code indicating the engine control module has detected excessive restriction in the Diesel Particulate Filter (DPF) caused by ash accumulation rather than recoverable soot. Unlike soot, ash cannot be burned off through normal or forced regeneration, so this typically signals the DPF is reaching the end of its service life and needs cleaning or replacement. The condition reduces exhaust flow and can trigger reduced-power (limp) mode if left unaddressed. Typical repair costs on Mercedes-Benz range from $60 to $2,500, depending on the specific model and root cause.
Common Causes of P242F
- •DPF at end of service life with accumulated non-combustible ash from engine oil additives
- •Excessive oil consumption (worn rings/valve seals) loading the filter with ash
- •Use of non-low-ash (non-CJ-4/low-SAPS) engine oil
- •Repeated incomplete or failed regeneration cycles over time
- •Faulty DPF differential pressure sensor giving high restriction readings
- •Clogged or saturated DPF substrate requiring professional cleaning or replacement
P242F on Mercedes-Benz by Model
Mercedes-Benz B-Class(1 issue)
- OM651 Diesel DPF and EGR Clogging (B180 CDI / B200 CDI)2013-2019
The 2.2L OM651 diesel in B180 CDI / B200 CDI variants is prone to diesel particulate filter (DPF) blockage and EGR-valve carbon fouling, especially on short urban trips where the exhaust never reaches regeneration temperature. Symptoms include reduced power (limp mode), increased fuel consumption, frequent failed regenerations, and warning lights. Carbon buildup in the EGR valve and intake also causes hesitation and rough running. The OM651 timing chain can also stretch and rattle, compounding diesel reliability concerns.
Mercedes-Benz GLS(1 issue)
- OM656 Diesel Emissions System Clogging (EGR/DPF/AdBlue SCR) and Limp Mode2020-2025
EU-market GLS 350d/400d models with the OM656 3.0L inline-six diesel suffer from sensitivity in the exhaust aftertreatment chain. The EGR (AGR) valve, diesel particulate filter (DPF) and SCR/AdBlue system are sensitive to poor fuel quality, short-trip driving and temperature swings. Clogged DPF, a dirty/sticking EGR valve, or a faulty EGR differential-pressure sensor cause power loss, failed regenerations, dashboard warnings and limp-home mode. A German motor-talk owner thread on the GLS X167 400d documents poor acceleration that resolves after a restart, traced to a replaced EGR differential-pressure sensor under warranty. This primarily affects diesels not sold in the US, so it is especially relevant to the EU market.
Mercedes-Benz V-Class(1 issue)
- DPF Regeneration Failure / Blockage (Short-Trip Use)2015-2020
The Euro 6 diesel particulate filter on the W447 needs periodic high-temperature regeneration to burn off soot. V-Class vehicles used for short urban trips never reach regen temperature, so soot accumulates, regen attempts fail, and the DPF eventually clogs. This brings warning lights, sluggish performance, increased fuel consumption and limp mode (capped around 2,500 rpm). The aggressive Euro 6 emissions hardware makes the W447 particularly sensitive to short-trip duty.
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View P242F across all makes →Frequently Asked Questions
What does P242F mean on Mercedes-Benz?▼
P242F stands for "Diesel Particulate Filter Restriction - Ash Accumulation (Bank 1)." P242F is a generic diesel emissions code indicating the engine control module has detected excessive restriction in the Diesel Particulate Filter (DPF) caused by ash accumulation rather than recoverable soot. Unlike soot, ash cannot be burned off through normal or forced regeneration, so this typically signals the DPF is reaching the end of its service life and needs cleaning or replacement. The condition reduces exhaust flow and can trigger reduced-power (limp) mode if left unaddressed. On Mercedes-Benz specifically, this code is documented across 3 models.
What causes P242F on Mercedes-Benz vehicles?▼
Common causes on Mercedes-Benz: DPF at end of service life with accumulated non-combustible ash from engine oil additives, Excessive oil consumption (worn rings/valve seals) loading the filter with ash, Use of non-low-ash (non-CJ-4/low-SAPS) engine oil, Repeated incomplete or failed regeneration cycles over time, Faulty DPF differential pressure sensor giving high restriction readings. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P242F on a Mercedes-Benz?▼
Repair costs on Mercedes-Benz range from $60 to $2,500, depending on the specific model and root cause.
Which Mercedes-Benz models have P242F documented?▼
Au7o has documented P242F on 3 Mercedes-Benz models: B-Class, GLS, V-Class.