What Renault codes (P0299, P0401, P0203, P0562, P0420, P0341) actually mean on Renault engines — the real cause, the common misdiagnosis, and the honest UK repair cost.
These are the OBD fault codes we see most often on Renault vehicles in the workshop, with the real cause on Renault engines rather than the generic textbook definition, plus the honest independent-garage cost.
Renault fault codes explained
- P0299 — Turbo underboost on Renault — 1.5 dCi K9K and 1.6 dCi R9M commonly suffer turbo oil starvation and actuator failure. Typical UK cost £250–£1800.
- P0401 — EGR flow insufficient on Renault 1.5/1.6/2.0 dCi — sticky EGR valve and intake carbon, often paired with swirl flap issues on dCi 130/160. Typical UK cost £160–£680.
- P0203 — Injector circuit Cylinder 3 on Renault 1.5/1.6/2.0 dCi — Delphi injectors fail electrically, plus wiring harness corrosion on vans. Typical UK cost £180–£720.
- P0562 — System voltage low on Renault — alternator decoupler pulley failure on 1.5 dCi (often misdiagnosed as battery) plus harness corrosion on vans. Typical UK cost £80–£420.
- P0420 — Catalyst efficiency below threshold on Renault — 1.2 TCe, 1.6 dCi rare, but 1.2 TCe is the headline case. Typical UK cost £260–£1400.
- P0341 — Camshaft position sensor performance on Renault — 1.5 dCi K9K and 1.2 TCe H5F sensor failure. Typical UK cost £60–£260.
- P0011 — VVT 'A' over-advanced Bank 1 on Renault — 1.2 TCe H5F and 1.6 dCi R9M VVT solenoid and oil sludge. Typical UK cost £65–£480.
- P0087 — Fuel rail pressure too low on Renault — 1.5 dCi K9K and 1.6 dCi R9M lift pump / DRV. Typical UK cost £180–£1300.
- P2002 — DPF efficiency below threshold on Renault — K9K dCi DPF clogged with belt-in-oil debris (newer engines) and Megane regen failure. Typical UK cost £180–£1600.
- P2463 — DPF soot accumulation on Renault dCi — K9K/R9M over-soot, belt-in-oil contamination risk. Typical UK cost £180–£1600.
Codes are generic across manufacturers, but the fix is not. The same code on a Renault 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 Renault
A £20 reader pulls generic engine codes and nothing else. On a Renault 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 Renault
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 Renault 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 Renault 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 Renault? Any generic OBD-II reader will pull engine codes from a Renault built after 2001, but manufacturer-level codes from the gearbox, ABS and body modules need a tool that speaks the Renault protocols. That is why a garage scan often finds codes a cheap reader misses.
Will clearing a Renault 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 Renault 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.