If I suspect a faulty control board, how can I confirm it's the issue causing the E6 error?

Diagnosing a faulty control board requires more advanced troubleshooting. You'll need to check the board for any visible signs of damage (burnt components, swollen capacitors). Using a multimeter, you can test the voltage levels at specific points on the board as outlined in the service manual. Replacing the board is often the only way to confirm if it's the problem, but it's best left to a qualified technician.