p0446
Moderate
GMC · Trucks
EVAP Vent Control Circuit
Quick Answer
Error code P0446 on your GMC Trucks means: EVAP Vent Control Circuit. This is usually fixable — see the step-by-step guide below.
Affected Models
Likely Causes
How to Fix It
1
Inspect EVAP vent filter element
2
Test vent solenoid resistance with ohmmeter
3
Check wiring harness for damage
4
Verify vacuum supply to vent valve
5
Replace vent solenoid if testing confirms failure
Pro Tip
This fix requires some technical knowledge. If you're unsure about any step, consider contacting support or a qualified technician.
Parts You May Need
EVAP vent solenoid
Vent filter element
Wire harness connector
Vacuum tubing
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