2002 cavalier po440 code
My mom called me and informed me that her check engine light had come on. I checked the code and it was PO440. My mom'* car is a 2002 cavalier with a 2.2 L engine.
My brother and I started with changing out the gas cap and driving the car some. It took about a week before the light came back on and it had the same code. PO440.
I went to our local pull a part and got an extra canister, vent valve, purge valve, and vacuum lines. I started by changing out the canister and vent valve. It'* the easiest to get to. My mom called me and told me the light came back on. I checked the code and this time it was a PO446. Which showed the vent valve was not functioning right. I put her old vent valve back on and changed the wire connection to the vent valve. Checking the wires to make sure they had continuity before plugging it in (seen there was a tsb out there for this).
She drove it for about a week before the light came back on. This time it was back to the PO440 code. We changed the purge valve on the back of the motor and checked to make sure there was battery voltage to the purge valve. The code has come back again.
Since this is a tough code to diagnose is it possible to attach a connector to the green evap test port and attach a vacuum gauge to see if vacuum is actually being pulled while driving it?
All the vacuum lines visually look good and don't look broken or cracked.
Does anyone have any other suggestion as to what to check or look for?