Error Code Slow Amber Flash
Info

York TM9V080B12MP11 Error Code Slow Amber Flash: Normal Operation - Call for Heat

TL;DR
Your furnace is actively heating in response to a thermostat request — this is normal operation.
Disclaimer
This article is for informational purposes only and does not guarantee the accuracy or completeness of the information provided. Always turn off power and gas supply before attempting any repairs. If you smell gas, leave immediately and call your gas company. Consult a licensed HVAC technician for diagnosis and repair. Any actions taken based on this information are at your own risk.

What Does Code Slow Amber Flash Mean?

A slow-flashing amber LED on the York TM9V080B12MP11 control board means the thermostat is calling for heat and the furnace is either starting up or actively running a heating cycle. The two-stage variable-speed furnace is managing its startup sequence or modulating its output to meet the heating demand. This is completely normal.

During a typical cycle, the inducer motor starts first, followed by the pressure switch closing, the igniter warming up, the gas valve opening, and the burners lighting. The variable-speed ECM blower ramps up gradually to its target speed. The two-stage design means the furnace may operate at low fire for moderate demand and switch to high fire when more heat is needed.

If your furnace does not appear to be producing heat despite the amber flash, the startup sequence may be stalling at one of its stages. Watch for the LED to change to a red flash pattern, which would indicate a specific fault.

Contact a licensed HVAC technician if any of these apply:

Sources

  1. Installation Manual - Residential Gas Furnace Models TM9V*MP (96% AFUE Two Stage Variable Speed ECM Multi-position)

✓ Verified against manufacturer service manual — March 2026