Help with p0455 2019 tahoe 5.3

[Jeremy Stephens]

I am aware im posting for a 2019 in a 2018 subforum. The tahoe runs a year behind the trucks. I have a 2019 tahoe 5.3 that just gave a p0455 code. Mass evap leak. I do have a upr catch can installed but I don't think it is the culprit. 

The only symptoms the truck has is a slight mileage drop and a smell in the cabin of used oil that comes and goes.

I do not have issues filling the tank with fuel, no gurgling or anything. 

I did order a vapor can purge solenoid that installs near the throttle body just to have a starting point.

I have not seen any loose hoses. 

Is there a repeat offender that causes this code?

Where else should I look?

[newdude]

1 hour ago, Jeremy Stephens said:

I am aware im posting for a 2019 in a 2018 subforum. The tahoe runs a year behind the trucks. I have a 2019 tahoe 5.3 that just gave a p0455 code. Mass evap leak. I do have a upr catch can installed but I don't think it is the culprit. 

The only symptoms the truck has is a slight mileage drop and a smell in the cabin of used oil that comes and goes.

I do not have issues filling the tank with fuel, no gurgling or anything. 

I did order a vapor can purge solenoid that installs near the throttle body just to have a starting point.

I have not seen any loose hoses. 

Is there a repeat offender that causes this code?

Where else should I look?

 

 

Large leak would be a damaged EVAP canister, stuck open EVAP vent valve, stuck closed purge valve or blocked purge line.

 

Ideal thing instead of throwing parts at it is a scan tool and a smoke test.  Smoking the system and then commanding the vent solenoid and purge solenoid would verify their operation.  It can also pinpoint a leak elsewhere say the fuel sending unit, the top rusted and a hole opened up.  

Edited February 11, 2023 by newdude

[Jeremy Stephens]

Thanks, I appreciate the help. Is there a decently affordable scan tool for this application?

[newdude]

12 minutes ago, Jeremy Stephens said:

Thanks, I appreciate the help. Is there a decently affordable scan tool for this application?

 

 

Around $1000 for a good bi-directional diagnostic tool.  There might be some in the 600-800 range but not sure.  Smoke machine, not cheap.  

 

Or its $150-200 for a shop to smoke and diag it.  

Edited February 11, 2023 by newdude