What Citroen codes (P244A, P0401, P0562, P0299, P0420, P0016) actually mean on Citroen engines — the real cause, the common misdiagnosis, and the honest UK repair cost.
These are the OBD fault codes we see most often on Citroen vehicles in the workshop, with the real cause on Citroen engines rather than the generic textbook definition, plus the honest independent-garage cost.
Citroen fault codes explained
- P244A — Differential pressure across DPF too low — on Citroen 1.6/2.0 HDi this is usually the pressure sensor or split pipework, not the DPF. Typical UK cost £60–£1800.
- P0401 — EGR flow insufficient on Citroen 1.6/2.0 HDi — identical PSA-group issue as Peugeot, very common on C3/C4/Berlingo doing short runs. Typical UK cost £180–£720.
- P0562 — System voltage low on Citroen — PSA Smart Charging system issues plus BSI (body computer) charging-strategy faults common on C3/C4. Typical UK cost £100–£420.
- P0299 — Turbo underboost on Citroën — PSA HDi VGT actuators and PureTech wastegate solenoids are the typical failure points. Typical UK cost £160–£1500.
- P0420 — Catalyst efficiency below threshold on Citroën — PSA THP and PureTech petrols suffer cat degradation from oil burning. Typical UK cost £240–£1300.
- P0016 — Crank/cam correlation Bank 1 on Citroën — 1.6 THP/VTi Prince engine timing chain stretch (DS3, C3, C4 Picasso). Typical UK cost £600–£2400.
- P2002 — DPF efficiency below threshold on Citroën HDi — same DV6/DW10 Eolys-additive story as Peugeot. Typical UK cost £140–£1400.
- P0087 — Fuel rail pressure too low on Citroën — 1.6/2.0 HDi mirroring Peugeot's lift pump / DRV story. Typical UK cost £180–£1400.
- P2463 — DPF soot accumulation on Citroën HDi — same Eolys/DPF story as Peugeot (C3/C4/Berlingo). Typical UK cost £140–£1400.
Codes are generic across manufacturers, but the fix is not. The same code on a Citroen usually points at a different component than it would on another make, which is why a make-specific diagnosis saves money before any parts are bought.
Reading codes properly on a Citroen
A £20 reader pulls generic engine codes and nothing else. On a Citroen the useful information often sits in the gearbox, ABS, body or comfort modules, and those need a tool that talks the manufacturer protocols. Just as important is the freeze-frame data stored with the code: engine speed, load, coolant temperature and fuel trims at the exact moment the fault was logged. That snapshot is usually what separates a failing sensor from a real mechanical problem, and it is the first thing we look at before anything is unbolted.
Why the same code costs different money on a Citroen
Each code on this page has a cost range rather than a price because the cheap cause and the expensive cause log identically. A split hose and a failed turbo can both set a boost code. Access matters too — some Citroen engines put the awkward part behind half the front end, and the labour, not the part, is what moves the bill. An honest quote names which cause has been confirmed and what the repair for that specific cause costs.
Getting a Citroen fault diagnosed
Bob's Mechanical Repairs is an independent, family-run garage in Birnam, Dunkeld, Perthshire, a couple of minutes off the A9. Bob has 32 years on the tools, and diagnostics are charged as diagnostic time with the findings explained in plain English and the repair priced before any work is agreed. An MOT is £54.85 if the car is due one at the same time.
Common questions
How do I read fault codes on a Citroen? Any generic OBD-II reader will pull engine codes from a Citroen built after 2001, but manufacturer-level codes from the gearbox, ABS and body modules need a tool that speaks the Citroen protocols. That is why a garage scan often finds codes a cheap reader misses.
Will clearing a Citroen fault code fix it? No. Clearing the code only erases the record. If the fault is still present it returns on the next drive cycle, and in the meantime the readiness monitors are reset, which can stop the car passing an emissions check.
How much is a Citroen diagnostic at an independent garage? An hour of diagnostic time is typically £50–£90 in the UK, against £110–£180 at a main dealer. It almost always costs less than the part it stops you buying by mistake.