Diagnostic trouble code P0306 on your 2024 GMC Terrain indicates a cylinder 6 misfire detection, creating an immediate diagnostic contradiction. The 2024 Terrain uses a four-cylinder engine exclusively, meaning there is no sixth cylinder to experience a misfire.
2024 Terrain Powertrain
The 2024 GMC Terrain uses the 1.5-liter turbocharged four-cylinder engine. This direct-injected turbo engine features only four cylinders numbered 1-4. No six-cylinder option is available.
Code Investigation
Since the Terrain lacks cylinder 6, P0306 represents diagnostic system malfunction. Possible causes include scanner errors, ECM software issues, or aftermarket device interference.
Diagnostic Steps
Verify with GM diagnostics. Remove OBD-II accessories. If symptoms exist, diagnose cylinders 1-4.