What Audi codes (P0171, P0341, P2015, P0420, P0401, P0203) actually mean on Audi engines — the real cause, the common misdiagnosis, and the honest UK repair cost.
These are the OBD fault codes we see most often on Audi vehicles in the workshop, with the real cause on Audi engines rather than the generic textbook definition, plus the honest independent-garage cost.
Audi fault codes explained
- P0171 — System too lean (Bank 1) on Audi — PCV diaphragm in the rocker cover on the 2.0 TFSI EA888, plus common diverter valve failures. Typical UK cost £140–£380.
- P0341 — Camshaft position sensor performance on Audi — on 2.0 TFSI it's the cam follower and HPFP wear, on 3.0 TDI it's the timing chain. Typical UK cost £50–£4500.
- P2015 — Intake manifold runner position sensor / flap motor — the famous 2.0 TDI CR P2015 fault on Audi/VW/Skoda. Typical UK cost £320–£750.
- P0420 — Catalyst efficiency on Audi petrol — on TFSI engines this is regularly the rear O2 sensor or oil consumption (cat-fouling), not the cat. Typical UK cost £160–£1100.
- P0401 — EGR flow insufficient on Audi 1.9/2.0/3.0 TDI — same VAG-group issue as VW but more often combined with intake-manifold carbon problems on A4/A6. Typical UK cost £250–£950.
- P0203 — Injector circuit Cylinder 3 on Audi 2.0/3.0 TDI — same VAG injector platform as VW but A4/A6 access is tighter; IMA coding is mandatory. Typical UK cost £300–£1200.
- P0106 — MAP sensor performance on Audi 2.0 TSI/TFSI and 2.0 TDI — same VAG MAP/IAT sensor failures as VW, plus PCV diaphragm issues on EA888. Typical UK cost £100–£360.
- P0562 — System voltage low on Audi — VAG battery registration mandatory; missing it is the #1 cause on A3/A4/A6 post-2010. Typical UK cost £100–£480.
- P0100 — MAF circuit malfunction on Audi — same VAG Bosch HFM failures as VW, plus more common across A4/A6 2.7/3.0 TDI V6. Typical UK cost £120–£360.
- P0304 — Cylinder 4 misfire on Audi — VAG TSI/TFSI coil failure, 2.0 TDI injector or glow plug, plus carbon-fouled plugs on 2.0 TFSI EA113. Typical UK cost £120–£720.
- P0741 — Torque converter clutch on Audi — applies to torque-converter autos (Tiptronic ZF6HP/8HP); DSG/S tronic uses different codes. Typical UK cost £320–£1600.
- P0299 — Turbo underboost on Audi — on 2.0 TFSI it's PCV/diverter valve, on 2.0/3.0 TDI it's the VGT actuator or charge pipe leaks. Typical UK cost £180–£1600.
- P0128 — Coolant temp below thermostat regulating temperature on Audi — same EA888/EA189 thermostat housing issue as VW. Typical UK cost £160–£620.
- P0011 — Intake cam over-advanced on Audi — EA888 chain tensioner failure and VVT solenoid sludging. Typical UK cost £240–£2200.
- P0301 — Cylinder 1 misfire on Audi — coil pack, injector or carbon-build-up on direct-injection EA888. Typical UK cost £60–£480.
- P0410 — Secondary air injection on Audi — 2.0 TFSI and 1.4 TSI combi-valve and pump failures. Typical UK cost £180–£950.
- P0430 — Bank 2 cat efficiency on Audi V6/V8 — typically upstream misfire damage, lazy rear O2 or coolant ingestion on 3.0T/4.2 FSI. Typical UK cost £260–£2800.
- P0302 — Cylinder 2 misfire on Audi — EA888 coil pack or EA189 injector copper-washer leak. Typical UK cost £85–£750.
- P0016 — Crank/cam correlation Bank 1 on Audi — 1.4/1.8/2.0 TSI EA888/EA111 chain tensioner failure, rattle on cold start. Typical UK cost £750–£2200.
- P0087 — Fuel rail pressure too low on Audi diesel — HP pump wear or in-tank lift pump on 2.0/3.0 TDI common rail. Typical UK cost £180–£1800.
- P2002 — DPF efficiency below threshold on Audi TDI — clogged DPF, failed regen sequence on 2.0/3.0 TDI. Typical UK cost £180–£1800.
- P0017 — Crank/cam correlation Bank 1 sensor B on Audi — exhaust cam adjuster fault on EA888/EA111 (sister code to P0016). Typical UK cost £750–£2200.
- P0089 — Fuel pressure regulator on Audi — 2.0 TFSI HPFP weak roller follower and 2.0/3.0 TDI DRV. Typical UK cost £180–£1600.
- P0234 — Turbo overboost on Audi — 2.0 TFSI EA113/EA888 wastegate actuator and 3.0 TFSI supercharger bypass. Typical UK cost £140–£850.
- P0193 — Fuel rail pressure sensor high on Audi — 2.0 TFSI / TDI sensor failure (false high reading). Typical UK cost £150–£380.
- P0507 — Idle speed higher than expected on Audi — vacuum leak from PCV / cracked intake hoses on 1.8/2.0 TFSI. Typical UK cost £140–£480.
- P0455 — EVAP gross leak on Audi — fuel cap, purge valve and charcoal canister vent failure. Typical UK cost £25–£320.
- P2463 — DPF soot accumulation on Audi — EA189/EA288 TDI DPF over-soot from failed regens (sister code to P2002). Typical UK cost £140–£1800.
- P0118 — Coolant temperature sensor reading open-circuit on Audi — usually the sensor or its brittle plug, occasionally a thermostat housing leak soaking the connector. Typical UK cost £40–£260.
- P0030 — Bank 1 sensor 1 heater circuit fault on Audi TFSI — connector heat damage common on longitudinal engines. Typical UK cost £100–£340.
- P0036 — Bank 1 sensor 2 heater fault on Audi TFSI — sensor wear or heat-damaged connector on longitudinal engines. Typical UK cost £110–£360.
- P0402 — EGR flow excessive on Audi TDI — same EA189/EA288 carbon issue as VW, plus 3.0 TDI CR EGR cooler failures. Typical UK cost £280–£1400.
- P0130 — Bank 1 sensor 1 circuit fault on Audi TFSI — wideband sensor response failure on EA888/EA837. Typical UK cost £150–£460.
- P242F — DPF ash mass limit on Audi TDI — 2.0/3.0 TDI end-of-life DPF, more common on Sportback/estate short-run cars. Typical UK cost £850–£2500.
- P0421 — Warm-up cat efficiency below threshold on Audi TFSI — manifold cat failure on EA888, often preceded by coil pack or wideband sensor drift. Typical UK cost £400–£2100.
Codes are generic across manufacturers, but the fix is not. The same code on a Audi 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 Audi
A £20 reader pulls generic engine codes and nothing else. On a Audi 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 Audi
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 Audi 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 Audi 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 Audi? Any generic OBD-II reader will pull engine codes from a Audi built after 2001, but manufacturer-level codes from the gearbox, ABS and body modules need a tool that speaks the Audi protocols. That is why a garage scan often finds codes a cheap reader misses.
Will clearing a Audi 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 Audi 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.