HFC CEL actual code?

[roxta]

Hi Guys,

Did a search and couldn't find the actual code the engine throws when you install a HFC, just references to a CEL.
Has anyone scanned the CEL and knows the error? I've just had my engine rebuilt and threw in a HFC, just wanted to make sure that the HFC is the root cause.

[van462]

P0420

[punkalex1]

Sent from my SM-G920P using Tapatalk

[roxta]

Thanks guys. Guess I have some kinda small vacuum leak as I'm getting P0171 system too lean. My long term fuel trim is around 5-6% so not too bad...

[oshwi]

Do you have an o2 spacer on? If its working too efficiently it can cause a lean code

[van462]

Watch for oil leaks from the front and rear main seals. If your O2 lambda( may be called equivalance) is above 1.0 at idle there is an easy way to diagnose if it's an intake tract leak or an engine block leak. Remove the oil fill cap. Disconnect the pc to intake manifold hose from the intake manifold. Seal off the intake manifold with a Ziploc bag secured with a rubber band or tape wrapped tightly over the bag. This will hold for an idle run but won't withstand a full boost run.This allows the engine to vent gases thru the oil cap but isolates the pc valve and engine block leaks from the intake. Start and check the lambda reading again. If it goes to 1.0 the leak is in the block. If it remains above 1.0 it's leaking somewhere on the intake manifold itself or n80 valve. N80 leak not as likely it should trigger an additional code for evap.

Edit, since a hfc was installed. if an o2 space was used make sure it was placed on the rear o2 and not the front. Also a leaking turbo to hfc gasket or a loose o2 sensor can cause this code.