Electronic gas water heater attempts to light but shuts down with E02; burner lights briefly or not at all.

Safety warning: Turn off power and gas before servicing. Use a non-contact tester to confirm power is off.

• 1. Clean flame sensor: Remove the burner assembly and locate the flame sensor rod. Lightly polish the rod with fine abrasive pad until shiny. Avoid touching with bare fingers afterward.
• 2. Check wiring and ground: Inspect the flame sensor wire for damage or loose connections at both the sensor and control board. Verify the burner assembly has a solid metal-to-metal contact with the burner bracket and manifold for proper grounding. Tighten mounting screws.
• 3. Verify electrical polarity: At the outlet, use a receptacle tester to confirm hot, neutral, and ground are correctly wired. American Water Heaters electronic models often require correct polarity for flame sensing. If incorrect, have an electrician correct the wiring.
• 4. Inspect burner flame: Restore gas and power, then observe through the sight glass. The flame should be steady and blue, contacting the flame sensor. Yellow, lifting, or unstable flames can cause E02; clean burner ports and ensure proper combustion air.
• 5. Control board check: If the flame is stable and sensor is clean but E02 persists, the gas control valve/ignition control module may have a failed flame sense circuit and should be replaced by a qualified technician.