DPF ash saturation on Vauxhall diesel — Z19DTH and A20DTH end-of-life DPFs.
Vauxhall P242F — DPF ash saturation on Vauxhall diesel — Z19DTH and A20DTH end-of-life DPFs. Typical UK independent garage cost: £600–£1800.
What actually causes P242F on a Vauxhall
Astra H 1.9 CDTi: EGR/DPF share the intake carbon story — cars with high urban use hit P242F at 100–120k miles. Insignia 2.0 CDTi A20DTH sees P242F alongside the well-known timing chain wear at 90k miles.
Vauxhall engines that log P242F
- 1.9 CDTi Z19DTH (Astra H, Vectra C, Zafira B)
- 2.0 CDTi A20DTH (Insignia, Astra J)
- 1.7 CDTi A17DTS
How we diagnose P242F on a Vauxhall
- Tech2 DPF ash mass and regen history
- Fix upstream issues (EGR, injector spray) FIRST
- Off-vehicle ultrasonic clean where possible
- OE Delphi/Denso DPF if replacement needed
The common misdiagnosis to avoid
Replacing DPF without addressing the reason it saturated — EGR still carbon-locked will kill the new DPF fast. Fix EGR/injectors first, DPF second.
Vauxhall P242F repair cost in the UK
Expect £600–£1800 including parts and labour at an independent garage. Main-dealer quotes on Vauxhall 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
Astra H 1.9 CDTi — clean the EGR and check injectors before spending on a DPF. Root cause matters.
Codes usually seen alongside P242F on Vauxhall
- P2002
- P244A
- P0402
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.