G
p0449
Moderate
GMC · Trucks
EVAP Vent Valve Circuit
Quick Answer
Error code P0449 on your GMC Trucks means: EVAP Vent Valve Circuit. This is usually fixable — see the step-by-step guide below.
Affected Models
Likely Causes
  1. Failed vent solenoid valve
  2. Wiring issue in vent valve circuit
  3. Clogged EVAP charcoal canister
  4. Vacuum line damage
  5. PCM malfunction
How to Fix It
1
Locate EVAP vent valve under vehicle
2
Test solenoid valve with multimeter
3
Inspect vacuum hoses for damage
4
Check electrical connector for corrosion
5
Replace vent valve if solenoid test fails
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 valve solenoid
Vacuum hose
Electrical connector
Hose clamp
Related Error Codes
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