Audi P0455

EVAP gross leak on Audi — fuel cap, purge valve and charcoal canister vent failure.

Audi P0455 — EVAP gross leak on Audi — fuel cap, purge valve and charcoal canister vent failure. Typical UK independent garage cost: £25–£320.

What actually causes P0455 on a Audi

Audi P0455 — fuel cap first, then purge solenoid (N80), then charcoal canister vent valve. Smoke test reveals all.

Audi engines that log P0455

• A3/A4/A6 1.4/1.8/2.0 TSI
• Q3/Q5 2.0 TSI

How we diagnose P0455 on a Audi

1. Fuel cap replacement and test
2. Smoke-test EVAP
3. N80 purge valve test
4. Vent valve test

The common misdiagnosis to avoid

Charcoal canister replacement is rarely needed — solenoid is the usual fault.

Audi P0455 repair cost in the UK

Expect £25–£320 including parts and labour at an independent garage. Main-dealer quotes on Audi 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

Audi P0455 — fuel cap and N80 are 80% of these.

Codes usually seen alongside P0455 on Audi

• P0440
• P0441
• P0456

Symptoms drivers report with P0455

• Engine warning light appears within a mile of filling up — sometimes the cap wasn't clicked shut
• Strong smell of petrol vapour around the car after parking on a hot day
• MPG barely affected — you'll only notice on the fuel receipts over a month
• MOT emissions test passes but the MIL means an MOT visual fail on any car registered 2018+
• Paired codes: P0440 (generic EVAP), P0441 (purge flow), P0446 (vent circuit), P0455 keeps returning

Repairs that clear P0455

• Refit fuel cap
• Inspect hoses

For the generic, all-makes explanation of this code — meaning, every known cause and UK cost bands — see our P0455 guide.