BMW P242F

DPF ash accumulation on BMW N47/N57 diesel — end-of-life DPF, often at 130–160k miles.

BMW P242F — DPF ash accumulation on BMW N47/N57 diesel — end-of-life DPF, often at 130–160k miles. Typical UK independent garage cost: £900–£2400.

What actually causes P242F on a BMW

BMW N47/N57 DPFs are more durable than the PSA/VAG competition and often reach 150k+ miles. When P242F sets it's usually genuine end-of-life. INPA/ISTA reads exact ash mass in grams.

BMW engines that log P242F

• N47 2.0d (F30 320d, E90 320d)
• N57 3.0d (F10 530d, F30 335d)
• M47 2.0d (older 320d)

How we diagnose P242F on a BMW

1. ISTA DPF ash mass reading (grams)
2. Confirm > 120g and regen count high
3. Ultrasonic clean if cell OK — good success rate on N57
4. Genuine BMW DPF or reputable reman if replacement

The common misdiagnosis to avoid

Fitting a pattern DPF — BMW ECU logs a substrate error within 500 miles because differential pressure profile is wrong. Genuine BMW or reman-with-warranty only.

BMW P242F repair cost in the UK

Expect £900–£2400 including parts and labour at an independent garage. Main-dealer quotes on BMW are usually higher for the same job, and the spread exists because the cheap cause and the expensive cause throw the same code — pay for the diagnosis before you pay for parts.

Bob's workshop tip

BMW N57 530d — the DPF often cleans well. Try that route before £2,000 on a new one.

Codes usually seen alongside P242F on BMW

• P2002
• P244A
• P246C

Symptoms drivers report with P242F

• DPF warning light on the dash steady (not flashing) — often accompanied by 'Engine System Fault, Service Now'
• Reduced Engine Power warning / limp mode after another attempted regen
• Car has done multiple 'passive regens' recently (higher revs at motorway cruise, warm smell like burning) that ended incomplete
• MPG dropped 5–12 mpg over recent months as the DPF partially blocked
• Slight loss of turbo response and top-end power, engine feels 'flat'
• Exhaust smells 'hot' or 'sulphurous' after a long drive — sign of forced-regen attempts

Repairs that clear P242F

• Replace or professionally clean DPF

For the generic, all-makes explanation of this code — meaning, every known cause and UK cost bands — see our P242F guide.