P0442 on Your 2024 GMC Terrain
A P0442 code on your 2024 GMC Terrain indicates a small evaporative emission system leak detected by the engine control module. On a brand-new compact SUV, this is typically caused by something minor — and your warranty covers the repair completely.
EVAP System Overview
The 2024 Terrain's 1.5L turbocharged engine uses GM's standard EVAP system with a purge solenoid valve, vent valve solenoid, and charcoal canister. The ECM runs sealed-system pressure tests to detect leaks equivalent to approximately 0.020 inches. The Terrain's compact design means shorter EVAP routing and fewer connection points compared to GM's larger vehicles.
Likely Causes on a New Terrain
- Gas cap not fully seated (45%) — The single most common P0442 trigger. Ensure the cap clicks firmly into position after fueling.
- Gas cap gasket contamination (20%) — Dirt or debris on the gasket surface preventing a full seal.
- Factory EVAP connection issue (15%) — A vapor line fitting that vibrated loose during early driving.
- Vent valve solenoid defect (10%) — A rare manufacturing defect preventing complete sealing during the leak test.
- Purge solenoid valve defect (10%) — A factory seal imperfection in the purge valve.
What to Do
Check your gas cap first — remove, clean the gasket, and reseat firmly. If the code persists after a couple of drive cycles, bring your Terrain to a GMC dealer for warranty service. The dealer's GDS2 diagnostic system provides comprehensive EVAP testing. All repairs on a 2024 model are warranty-covered.
Cost Estimates (Reference — $0 Under Warranty)
- Gas cap replacement: $15–$35
- EVAP line repair: $80–$200
- Vent valve solenoid: $110–$240
- Purge solenoid valve: $110–$240
Full Warranty Coverage
Your 2024 Terrain is covered under GM's 3-year/36,000-mile basic warranty, 5-year/60,000-mile powertrain warranty, and federal 8-year/80,000-mile emissions warranty. EVAP components are covered under basic warranty. Do not pay out of pocket — all P0442 repairs should be free at your GMC dealer.