Fault codeP0455

MODERATE

Evaporative Emission Control System Tank Detected (gross leak)

What this code means

Evaporative Emission Control System Tank Detected (gross leak).

P0455 is a generic code: it means the same thing on every make. P0455 belongs to family P04xx — Emission controls. Its page explains how to read a code and groups all its codes by part.

Fuel vapour recovery (EVAP)

The EVAP system traps fuel vapour from the tank in a charcoal canister, then burns it in the engine through a purge valve. A vent valve and a pressure sensor let the control unit test the system for leaks, often after the car has been parked.

Symptoms

Like P0442, no effect on driving. The code indicates an outright leak: no vacuum builds in the evaporative system at all. It very often appears right after filling up — cap forgotten or not put back properly — and sometimes with a clear smell of petrol.

Common causes

Fuel cap missing, loose or of the wrong type
Hose disconnected or burst between tank, canister and engine
Vent solenoid stuck open
Broken canister, often after an impact or stone strikes
Rusted filler neck or failed tank gasket

How to diagnose it

Check the cap first, and do not hesitate to replace it: an original cap costs little and settles most cases. Clear the code and wait a few trips.

If the code persists, look for a disconnected hose by eye, especially near the canister — often under the rear of the car. A workshop smoke test shows a leak this size immediately.

Watch it live in Klaro

With an OBD2 adapter plugged in, these live readings show the part at work, when your car reports them:

Commanded evaporative purge
Evap system vapor pressure
Fuel level

What to do

Have it checked this week. The car remains usable, but the fault will not clear itself and will fail the roadworthiness test.

Clearing a code switches the light off but repairs nothing: if the fault remains, the code comes back. Clearing a fault code yourself →

Repair cost

Cap: €10 to €30. Hose: €5 to €40. Solenoid: €30 to €100. Canister: €80 to €300.

How to read this code

PPowertrain
0standardised code
4Emission controls
55P0455