p0454 p0455

[msarles1]

anyone ever tackle these 2 codes? if cleared will come back within 20 miles. any suggestions? 2009 denali 6.2

 

[OR VietVet]

P0454 is the EVAP system pressure sensor problems.

P0455 is the EVAP system :

• Missing or loose fuel cap
• Incorrect fuel filler cap used
• Fuel filler cap remains open or fails to close
• Foreign matter caught in fuel filler cap
• Leaking EVAP Canister
• Leaking EVAP System Hose
• Leaking Fuel Tank
• Faulty Fuel Tank Pressure Sensor

The common denominator is the pressure sensor. You can lead with that and cross your fingers. I did my entire system when I did mine but some do have luck here, going piece by piece.

 

[Joseph Garcia]

Welcome to the Forum from NH.

Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.

I hope that you will become a participating member in the Forum's discussions.

Pics of the truck, please.

I cannot personally help you with your question; however, other members on this Forum that are much more knowledgeable than me will chime in.


By pure definition:

P0454 is a diagnostic trouble code (DTC) for "Evaporative Emission Control System Pressure Sensor Intermittent". This can happen for multiple reasons and a mechanic needs to diagnose the specific cause for this code to be triggered in your situation.

The P0455 code indicates that there is a large leak in the EVAP system, but this is somewhat misleading. What the code really indicates is that the EVAP system has a gross leak.

 

[Fless]

The P0455 code indicates that there is a large leak in the EVAP system, but this is somewhat misleading. What the code really indicates is that the EVAP system has a gross leak.

Or it could mean that the fuel tank pressure sensor is giving faulty readings. Need a good diagnosis to pinpoint the issue. A purge and seal procedure would go a long way...