P0442 on Your 2023 GMC Yukon
A P0442 code on your 2023 GMC Yukon indicates the engine control module detected a small leak in the evaporative emission system. On a vehicle just one to two years old, the cause is typically minor and should be covered under your GM warranty.
EVAP System Overview
The 2023 Yukon's 5.3L V8, 6.2L V8, or 3.0L Duramax diesel share the T1XX platform. P0442 applies only to the gasoline V8 engines. The EVAP system includes a purge solenoid valve, vent valve solenoid (near the spare tire on full-size GM SUVs), and charcoal canister connected by vapor lines running along the frame. The ECM detects leaks of approximately 0.020 inches through pressure monitoring.
Common Causes on a Newer Yukon
- Gas cap not fully seated (45%) — The most common trigger. Ensure the cap is twisted until it clicks firmly.
- Gas cap gasket contamination (20%) — Dirt or debris preventing a complete seal.
- EVAP hose connection looseness (15%) — A vapor line fitting that loosened from road vibration during the first year of driving.
- Vent valve solenoid issue (10%) — A defect in the vent valve solenoid near the spare tire preventing complete sealing.
- Purge solenoid valve issue (10%) — A minor seal imperfection in the purge valve.
Recommended Action
Check and reseat your gas cap first. If the code persists after two to three drive cycles, schedule a warranty appointment at your GMC dealer. The GDS2 diagnostic system provides comprehensive EVAP testing. Under warranty, all diagnosis and repair costs are covered.
Cost Estimates (Reference — $0 Under Warranty)
- Gas cap replacement: $15–$40
- EVAP line repair: $100–$280
- Vent valve solenoid: $120–$270
- Purge solenoid valve: $130–$280
Warranty
Your 2023 Yukon is within GM's 3-year/36,000-mile basic warranty, which covers EVAP components. The 5-year/60,000-mile powertrain warranty and federal 8-year/80,000-mile emissions warranty provide additional safety nets. Do not pay out of pocket — this should be a no-cost warranty repair.