York, Luxaire and Coleman furnace flash codes

York's furnace controls store the last five faults and will replay them on demand — which makes them unusually good at diagnosing an intermittent problem, and unusually easy to wipe by accident.

Also covers: Luxaire, Coleman — same manufacturer, same controls, same codes.

York, Luxaire and Coleman are the same manufacturer and share integrated furnace control boards. These boards use colour as well as count: a green heartbeat means idle, an amber heartbeat means a call for heat, and counted red flashes are faults. Their most useful feature is a stored fault history — the last five faults, replayed by pressing the LAST ERROR button on the control board.

Worth knowing before you count

The stored history is the most valuable thing these boards offer and the easiest to destroy. Holding the same button for five seconds clears the memory. If a furnace has been faulting intermittently, get the history read before anyone resets anything.

How York furnaces signal codes

Colour comes first on these boards. A green heartbeat is idle, an amber heartbeat is a call for heat, and counted red flashes are faults — with rapid flashing and a solid LED as separate signals in their own right. The fault history works through the LAST ERROR button on the control board: press and release it for under five seconds and the LED replays up to five stored codes, newest first, with two seconds between them. Two green flashes means nothing is stored. Holding the button five seconds or longer clears the memory and confirms with three green flashes — and one documented limitation is that solid-LED control faults are never included in the replay. Because the button sits on the board inside the cabinet, next to live terminals, the reading itself is technician work; the useful thing a homeowner can do is know the history exists and ask for it to be read before anyone cycles power or resets the furnace.

The York codes people look up most

Seven red flashes — the one-hour lockout after ignition retries are exhausted — is the code behind most cold-morning searches. Three red flashes is the pressure switch refusing to close, a draft and venting question before it is a switch question. Four red is the open high limit, usually airflow; five red is a tripped rollout, which is combustion escaping where it should not be and is not a reset-and-hope code. Nine red points at grounding or reversed polarity — the house wiring rather than the furnace — and twelve red is an open hot surface igniter, the most predictable wear item on the list. Eleven red, a limit held open by blower failure, moves the diagnosis to the blower motor itself.

Which York furnaces these pages cover

These pages are written from the UTEC control board table in Johnson Controls technical service letter ST-045-09, covering boards 539617, 542760, 542766 and 542767 and their S1-series equivalents, fitted across York, Luxaire and Coleman single-stage PSC, two-stage PSC and two-stage ECM variable speed furnaces. The previous generation of White-Rodgers Emerson boards reads differently on ten counts, four of which change the diagnosis — the board part number, printed on a label on the board itself, settles which table applies.

What the common York fixes cost

Twelve red flashes ends at the hot surface igniter: $150–350 installed, part only $20–60 universal. Rapid amber's low flame sense current usually means flame sensor cleaning at $80–200. Pressure switch codes (three red, six red) run $150–400 with the flue checked first, and an open limit at four red is $150–350 plus finding the airflow cause. Eleven red's blower failure spans $400–700 for a PSC motor and $700–1,200 for an ECM — with the $150–350 capacitor-only fix worth ruling out on a PSC that hums but will not spin. A solid LED pointing at the control itself is $400–900 installed, plus $75–150 of diagnosis into what killed it.

York, Luxaire and Coleman

1 red flash — Flame sensed with the gas valve off
1 amber flash — Normal operation with a call for heat, Emerson boards
2 red flashes — Pressure switch stuck closed, or an inducer error
2 amber flashes — Normal operation with a call for second stage heat
3 red flashes — Pressure switch open, or first stage pressure switch open
3 double red flashes — Second stage pressure switch stuck open
3 amber flashes — Second stage heat present with no first stage call
4 red flashes — Open high limit switch
4 amber flashes — Cooling called with no fan call
5 red flashes — Open rollout switch
6 red flashes — Pressure switch cycle lockout
7 red flashes — One hour lockout after ignition retries
8 red flashes — Lockout on recycles, flame dropouts
9 red flashes — Grounding, reversed polarity, or reversed transformer leads
10 red flashes — Gas valve energised with no call for heat
11 red flashes — Limit switch open more than five minutes — blower failure
12 red flashes — Open hot surface igniter
Amber heartbeat — Normal operation with a call for heat
Fault code retrieval — How to read and clear stored fault codes on York UTEC boards
Green heartbeat — Normal operation, no call for heat, no active errors
Rapid amber flashing — Low flame sense current
Rapid red flashing — Twinning error or incorrect 24 volt phasing
Solid LED — Control fault detected
Steady off — No power to the board, or control failure
Which York control board you have — York used two control board generations with different code meanings

Other manufacturers

This site is a reference, not a substitute for a licensed HVAC technician. Gas appliances can leak carbon monoxide and cause fire. Anything involving gas lines, the heat exchanger, or the flame sensing circuit should be handled by a licensed professional. Pages are written with AI assistance from the sources listed on each page and checked against them before publishing.