Status LED flashes nine times, furnace may not start or may behave erratically.

Safety First: Turn off power before touching the control board or wiring.

This code indicates an internal fault in the control board.

• Power cycle: Turn off power at the service switch or breaker for at least 5 minutes, then restore power and observe if the code clears.
• Inspect board and connectors: Look for burnt traces, swollen components, or corrosion. Reseat multi-pin connectors firmly.
• Check for moisture: Ensure there are no water leaks from humidifiers, condensate lines, or roof/vent penetrations dripping onto the board.
• Verify proper grounding: Loose grounds can cause erratic board behavior. Tighten ground screws and ensure cabinet is bonded.

When to call a professional: If the 9-flash code persists after power cycling and visual inspection, the control board likely needs replacement and setup by a qualified technician.