A P0303 diagnostic code on your 2022 Cadillac XT6 indicates the engine control module has detected repeated misfires in cylinder 3. The three-row luxury crossover uses GM's proven 3.6L V6 engine.
3.6L V6 Engine Layout
The 2022 XT6 uses the LGX 3.6L V6 producing 310 horsepower with direct fuel injection. Cylinder 3 is located on the driver's side (left) bank at the rear position.
Common Causes
- Ignition Coil Failure: Individual coil-on-plug units can fail
- Spark Plug Wear: Iridium plugs eventually need replacement
- Fuel Injector Problems: Direct injection deposits
- Carbon Buildup: GDI technology leads to valve deposits
- Intake Manifold Leaks: Gasket or vacuum line failures
Diagnostic Approach
Use a GM-compatible scanner for detailed diagnostics. Monitor misfire counts and fuel trim data. Test ignition components through swap testing. Check for V6-specific issues like carbon buildup.
Repair Solutions
Replace failed ignition coils with AC Delco components. Install GM-specified iridium spark plugs. Clean or replace fuel injectors as needed. Consider carbon cleaning for higher mileage vehicles.