What Hyundai codes (P0011, P0420, P0171, P0299, P0016, P0087) actually mean on Hyundai engines — the real cause, the common misdiagnosis, and the honest UK repair cost.
These are the OBD fault codes we see most often on Hyundai vehicles in the workshop, with the real cause on Hyundai engines rather than the generic textbook definition, plus the honest independent-garage cost.
Hyundai fault codes explained
- P0011 — VVT actuator over-advanced on Hyundai 1.6 GDI / 2.0 GDI — often related to the well-documented Theta II / Gamma engine concerns and oil consumption. Typical UK cost £180–£600.
- P0420 — Catalyst efficiency on Hyundai — on 1.6 GDI petrol (Theta II family) the famous engine bearing failures damage the cat with debris. Typical UK cost £180–£1300.
- P0171 — System lean on Hyundai — Gamma 1.6 GDi intake valve carbon and PCV oil mist. Typical UK cost £20–£550.
- P0299 — Turbo underboost on Hyundai 1.6 CRDi and 1.0/1.4 T-GDi — VGT actuator or charge-pipe split. Typical UK cost £180–£1200.
- P0016 — Crank/cam correlation Bank 1 on Hyundai — Theta II 2.0/2.4 GDi chain wear and Kappa 1.0/1.4 T-GDi OCV. Typical UK cost £180–£2400.
- P0087 — Fuel rail pressure too low on Hyundai — 1.6 CRDi U2 lift pump and HP pump wear. Typical UK cost £180–£1400.
- P0234 — Turbo overboost on Hyundai — 1.6 CRDi VGT actuator stuck and 1.0/1.4 T-GDi wastegate. Typical UK cost £160–£1100.
- P2002 — DPF efficiency below threshold on Hyundai — 1.6/2.0 CRDi U2/R-line DPF clogging on i30/Tucson/Santa Fe. Typical UK cost £180–£2200.
- P0341 — Camshaft position sensor performance on Hyundai — Theta II / Gamma / Kappa CMP sensor. Typical UK cost £100–£400.
Codes are generic across manufacturers, but the fix is not. The same code on a Hyundai 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 Hyundai
A £20 reader pulls generic engine codes and nothing else. On a Hyundai 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 Hyundai
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 Hyundai 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 Hyundai 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 Hyundai? Any generic OBD-II reader will pull engine codes from a Hyundai built after 2001, but manufacturer-level codes from the gearbox, ABS and body modules need a tool that speaks the Hyundai protocols. That is why a garage scan often finds codes a cheap reader misses.
Will clearing a Hyundai 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 Hyundai 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.