York Furnace Slow Amber Flash
StatusShown as: Amber LED on two seconds, off two seconds, repeating
Normal operation with a call for heat. The control has received a W signal from the thermostat and is running the heating sequence. Not a fault.
Manual wording: “SLOW AMBER FLASH: Normal operation with call for heat.”
Documented for: TG8S, TG9S, TM9E, TM9V, TM8Y, TM9Y
Likely causes, most common first
- Normal heating operation with a thermostat call for heat
When to call a technician
No service needed. If the furnace is showing this code but no warm air reaches the rooms, have a technician check the blower and ductwork.
A York furnace throwing this code repeatedly has a reason — clearing the code without fixing the cause just hides it.
Sources
- Installation Manual - Single Stage PSC Residential Gas Furnaces, TG9S and GG9S Series (95.5% AFUE Multi-position), 1083287-UIM-A-0114 (Johnson Controls Unitary Products (York), TG9S*MP, GG9S*MP single-stage PSC 95.5% AFUE gas furnaces) · checked 2026-08-25
- Installation Manual - Single Stage PSC Residential Gas Furnaces, TG8S*MP / TGLS*MP / GG8S*MP / GGLS*MP (80% AFUE Multi-position / Standard Low NOx), 998491-UIM-B-1013 (Johnson Controls Unitary Products (York), TG8S*MP, TGLS*MP, GG8S*MP, GGLS*MP 80% AFUE single-stage gas furnaces) · checked 2026-08-25
- Installation Manual - Single Stage ECM Residential Gas Furnaces, TM9E Series (95% AFUE Multi-position), 1083163-UIM-A-0214 (Johnson Controls Unitary Products (York), TM9E*MP single-stage ECM 95% AFUE gas furnaces) · checked 2026-08-25
- Installation Manual - Two Stage Variable Speed ECM Residential Gas Furnaces, TM9V Series (96% AFUE Multi-position), 1083294-UIM-A-0114 (Johnson Controls Unitary Products (York), TM9V*MP two-stage variable-speed ECM 96% AFUE gas furnaces) · checked 2026-08-25