York furnace Fault code retrieval: How to read and clear stored fault codes on York UTEC boards
These boards store the last five faults and replay them on demand. Pressing the LAST ERROR button briefly plays them back, most recent first; holding it for five seconds clears the memory.
Applies to: York, Luxaire and Coleman gas furnaces using the UTEC integrated furnace control boards documented in Johnson Controls Unitary Products technical service letter ST-045-09, including boards 539617, 542760, 542766, 542767 and their S1-series equivalents.
What it means
Most furnace controls show you only what is happening now. York's UTEC boards keep an array of the last five faults and will replay them, which changes what is possible during a service call — an intermittent fault that has cleared can still be recovered. The procedure is specific. Press and release the LAST ERROR button for more than a fifth of a second and less than five seconds, and the LED flashes up to five stored codes, newest first, with two seconds between them. If nothing is stored, you get two green flashes. Holding the same button for at least five seconds clears the memory and confirms with three green flashes. One limitation is documented: solid LED error codes are not replayed.
Most common causes
- Not applicable — this is a procedure rather than a fault condition.
How to diagnose it
- Locate the LAST ERROR button on the control board. Reading the codes means opening the cabinet and working next to live terminals, so this is a technician task rather than a homeowner one.
- Press and release for more than one fifth of a second and less than five seconds to replay stored codes.
- Expect the newest fault first and the oldest last, with two seconds between each.
- Two green flashes means no faults are stored.
- Note that solid LED error codes are not included in the replay, so a control fault indicated by a steady light will not appear in the history.
How to fix it
- Do not clear the fault memory before a technician has read it. The stored history is the most useful thing the board has to offer on an intermittent fault.
- To clear deliberately, hold the LAST ERROR button for at least five seconds and look for three green flashes confirming the memory is empty.
- Record the codes before clearing them, in order, since the sequence itself is informative.
- This procedure means working at a live control board inside the furnace cabinet, alongside high voltage terminals. It is technician work, in the same way the equivalent Carrier procedure is. What a homeowner can usefully do is know the stored history exists and ask for it to be read before anyone clears it.
Notes
The five-fault history is genuinely valuable and easy to destroy. The instinct on arriving at a dead furnace is to cycle power or press buttons, and either can lose a record that would have explained an intermittent problem that has defeated two previous visits.
Related
- Green heartbeat — Normal — no call for heat
- 9 red flashes — Grounding, reversed polarity, or reversed transformer leads
All codes for this manufacturer
York, Luxaire and Coleman furnace flash codes — every code, with what differs between models.