When it comes to BMW vehicles, one of the most common diagnostic trouble codes is P0455, which is an EVAP Control System Large Leak Detected code. This code is triggered when the powertrain control module (PCM) detects a leak in the EVAP system. The EVAP system collects and stores fuel vapors from the fuel tank and sends them to the engine for combustion. To diagnose this code, the engine must be started, the battery voltage must be at least 11.5 volts, all electrical components must be off, the parking brake must be engaged to keep the daytime running lights off, the automatic transmission must be in the park, and the exhaust system must be adequately sealed. The underlying causes of this code may include aftermarket EVAP hardware that is non-conforming to specifications, an EVAP canister tube, EVAP canister purge outlet tube, or EVAP return tube that is disconnected or cracked, a stuck closed EVAP canister purge valve, or a damaged canister.
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Causes and Solutions of P0455
| Cause | Solution |
|---|---|
| Aftermarket EVAP hardware non-conforming to specifications | Replace with OEM parts |
| EVAP canister tube, EVAP canister purge outlet tube, or EVAP return tube disconnected or cracked, or canister is damaged | Replace the damaged parts |
| EVAP canister purge valve stuck closed, or canister damaged | Clean or replace the canister purge valve |
| Fuel | Repair or replace the fuel system components |
Damaged Fuel System Components
One of the most common causes of the BMW Code P0455 is a damaged fuel system component, such as a fuel line, fuel filter, or fuel pump. If the fuel system component is damaged, the fuel system pressure will drop, and the EVAP system will not be able to collect and store fuel vapors from the fuel tank properly. To diagnose this issue, the fuel system must be inspected for leaks, and any damaged components must be replaced.
Stuck Closed EVAP Canister Purge Valve
The EVAP canister purge valve is responsible for releasing the stored fuel vapors from the EVAP system. If the purge valve is stuck closed, the EVAP system cannot release the fuel vapors properly, and the P0455 code will be triggered. To diagnose this issue, the purge valve must be checked for proper operation, and if it is found to be stuck closed, it must be cleaned or replaced.
Non-Conforming Aftermarket EVAP Hardware
Some aftermarket EVAP hardware may not be conforming to the manufacturer’s specifications, which can lead to the P0455 code being triggered. To diagnose this issue, the EVAP system must be inspected for aftermarket components, and if any are found, they must be replaced with original equipment manufacturer (OEM) parts.
Conclusion: How to Fix BMW Code P0455
The BMW Code P0455 is an EVAP Control System Large Leak Detected code, which is triggered when the powertrain control module (PCM) detects a leak in the EVAP system. To fix this code, the engine must be started, the battery voltage must be at least 11.5 volts, all electrical components must be off, the parking brake must be engaged to keep the daytime running lights off, the automatic transmission must be in the park, and the exhaust system must be adequately sealed. The underlying causes of this code may include aftermarket EVAP hardware that is non-conforming to specifications, a stuck closed EVAP canister purge valve, a damaged fuel system component, or a damaged canister. The EVAP system and fuel system components must be inspected to diagnose and repair this issue, and any damaged parts must be replaced. By following these steps, you can quickly fix the BMW Code P0455 and keep your vehicle running smoothly.