PCV hose cause code?

I’ve had a check engine light on in my 3.5 Pontiac G6 for awhile now. It’s an emission code (can’t remember what code but evap leak). The solenoid by canister was also tripping a code that disappeared after I changed it. However, the evap code still persists. Last night while changing my oil I noticed the intake air hose to the crankcase had broke at the case and wasn’t connected. It’s the hose that runs from the engine intake to the crankcase for the PCV system.

Im replacing the hose regardless, but my question is; would the intake hose for the PCV system being loose cause an evap leak code?

Im thinking no but it’d be nice if it was that simple.


Please post your exact fault code and I will post some bulletins, if I can

As far as that broken PCV hose, in my opinion, that would cause a P0171 lean code, not an evap code

If the evap code was for a leak, check if the cap seal is intact. Also check to make sure the threaded portion hasn’t partially separated from the cap

I’ll have to dig around and see if I can find the code.

I changed the gas cap as well, after I’d intermittently get the “check gas cap” on the display. Still didn’t help anything.


Thanks for the added information

Since you got the “check gas cap” message, you definitely have an evap minor or major leak code

That much we know. Any other codes we don’t know about, until you post them

I have a question . . .

Has any professional mechanic attempted to diagnose and repair your evap problems? The guy would ideally have a scan tool capable of performing the evap service bay test and and also commanding the vent valve closed, so that he could use the evap/smoke machine to check for leaks.

Here’s another scenario, which I have personally experienced, but is a little more uncommon. An electrically faulty fuel tank pressure sensor can generate an evap leak code. I am NOT advising you to run out and replace this just yet, as it can be hard to get to, and you’d have to be sure it is the problem.

Food for thought . . .

There’s no connection between the PCV and evap. As db4690 mentioned, you likely have an evap system leak.

The evap leak is the only code I have. At first, there was an evap code and vent solenoid code. The solenoid was only 20 bucks so I figured I’d replace it and give it a shot. Now the evap code is the only code I have. This has all taken place in the last year and a half. I have a few mechanic friends I used to work with with the scanner, just haven’t made it out to their place yet. Eventually I’ll get it in and hooked up to the smoker.


Too bad you aren’t my neighbor

My scanner is GM capable, and I have my own personal evap/smoke machine in my garage

Since my shop’s evap/smoke machine broke, and it became clear it won’t be replaced any time soon, I bought my own and claimed it as a tax deduction. I bring it to work as needed.


That is too bad. Lol.

There’s no other way besides smoke to find the leak is there? I’ve visually inspected the tubes but didn’t find anything.

Often the smoker can’t even find it, but it’s your best bet from here.
Sometimes I wonder if many of these EVAP codes aren’t triggered by bad Fuel Tank Pressure Sensors (FTPs), poor sensitivity perhaps. An open FTP would trigger a code, but I’m not sure a poor sensitivity curve would.


The smoke certainly helps

You might be able to see a bad cap (bad seal, threads separating from the housing) or rotted and/or cracked evap hoses, as well as a rusted filler pipe or leaking fuel filler hose