P0446 Code 01 & 02 on 1998 GMC S10 4.3L Engine - Evaporative Emission System Issue
I have a 1998 GMC S10 with a 4.3-liter engine and the check engine light has come on. The diagnostic trouble codes detected are P0446-01 and P0440-02. Generic code description: Evaporative Emission Control System Vent Control Circuit Malfunction. My vehicle has been driven approximately 170,000 kilometers with no major engine work performed in the past two months (only a Positive Crankcase Ventilation valve replacement). Can anyone help me understand what this code means in simpler terms? Is there a specific component or location where I should look for the fault? Thank you. P-Nut
You'll likely need to consult a repair manual or at least understand how the evaporative emissions system works on this model. A solenoid or vent valve is a common suspect in such cases. I've personally replaced these components on multiple GM trucks, so it's worth checking those parts first.