The P0206 code indicates an issue with the injection circuit for cylinder 6. Since your engine is running fine, here are a few things you might want to check:
1. Wiring and Connectors: Inspect the wiring and connectors associated with the fuel injector for cylinder 6. Look for any signs of damage, corrosion, or loose connections.
2. Fuel Injector: Even though the engine runs well, it might be worth testing or swapping the injector for cylinder 6 with one from another cylinder to see if the code changes.
3. ECM/PCM Update: Sometimes, a simple software update to your engine control module can resolve issues like this. It might be worth checking with a dealer or a trusted mechanic to see if there are any available updates.
4. Ignition System: While less likely since the engine isn't running rough, it wouldn't hurt to check the spark plug and ignition coil for that cylinder, just to rule out any underlying issues.
5. Clearing the Code: If you haven’t already, try clearing the code and see if it comes back. Sometimes codes can be triggered by transient issues, especially with used vehicles.