When your 2021 GMC Yukon displays diagnostic trouble code P0306, the engine control module has detected misfires in cylinder 6. The 2021 Yukon uses V8 engines exclusively, making P0306 a valid diagnostic code requiring systematic troubleshooting.
2021 Yukon Engine Options
The 2021 GMC Yukon offers the 5.3-liter V8 producing 355 horsepower and the 6.2-liter V8 delivering 420 horsepower. Both engines have eight cylinders with Dynamic Fuel Management (DFM) cylinder deactivation technology.
DFM System Considerations
Both Yukon V8 engines feature DFM that can deactivate cylinders including #6 during light-load cruising. DFM lifter or solenoid issues can cause misfire symptoms during cylinder deactivation transitions.
Common Causes
Ignition coil failure, spark plug wear, DFM lifter problems, and fuel injector issues are typical across Yukon V8 engines.