Lennox Furnace Error Code E263

E263 means the furnace has entered a soft lockout because it exceeded the maximum number of allowed ignition recycles, with the last recycle ending in flame failure. The control board monitors every ignition attempt, and when repeated failures occur, it stops retrying to prevent unsafe conditions. The underlying cause is consistently tied to flame failure, which the E240 diagnostic path is designed to address.

The first step is to follow the E240 diagnostic path, since E263 is triggered by repeated E240 flame failure events. Start by inspecting the flame sensor for contamination and the hot surface igniter for damage, then verify gas pressure and check the burner assembly for debris. A qualified technician should perform this diagnosis, especially steps involving gas pressure measurement and component testing.

Repair costs depend entirely on what component is causing the repeated flame failures. Cleaning the flame sensor is inexpensive and sometimes covered under a standard diagnostic visit fee, while replacing a hot surface igniter typically costs between $150 and $350 including parts and labor. If the gas valve or control board is at fault, costs can range from $300 to $700 or higher depending on the specific parts required.

Because E263 is a soft lockout, the furnace may restart on its own after a waiting period without a manual reset. However, simply resetting the unit without addressing the root cause will result in the same ignition failures recurring and the code returning. A proper repair of the underlying flame failure issue is required to prevent the code from coming back.

The soft lockout is actually a safety feature that prevents the furnace from continuing to attempt ignition in an unsafe manner, so the unit has already stopped running on its own. You should not attempt to repeatedly reset and restart the furnace without identifying the cause, as doing so could mask a more serious fault. Leave the furnace off and contact a qualified technician to diagnose the flame failure issue.