HVAC Code Lookup

York Furnace: 2 Flashes

A York furnace LED pattern starting with 2 flashes matches 5 documented codes: 2 red flashes, 2 green flashes, 2 amber flashes (YP9C modulating), 2 red flashes (YP9C modulating), 2 green flashes (YP9C modulating). Watch the full pattern (short vs. long flashes) to tell them apart — all 5 are explained below.

Code 2 red flashes: The pressure switch is closed when it should be open

Soft lockoutShown as: Two red flashes, then a two-second pause, repeating

The pressure switch is closed when it should be open. Before each heat cycle the control checks that the pressure switch contacts are open; if they are already closed it will not allow the ignition sequence to start.

Manual wording: “2 RED FLASHES: This indicates that the pressure switch is closed when it should be open... Check for a faulty pressure switch or miswiring.”

Documented for: TG8S, TG9S, TM9E, TM9X, TM8X, TM9T, TM8T, TM9V, TM8Y, TM9Y

Likely causes, most common first

  1. Faulty pressure switch stuck closed
  2. Miswired pressure switch

What you can safely check yourself

  • Turn the furnace off at the service switch for a minute and back on once to see whether the code clears

When to call a technician

A stuck-closed pressure switch is a safety interlock failure. It must be tested and replaced by a technician - never jumper or bypass it.

A York furnace throwing this code repeatedly has a reason — clearing the code without fixing the cause just hides it.

Sources

Full page for York code 2 red flashes

Code 2 green flashes: There are no error codes stored in the control board's memory

StatusShown as: Two green flashes after pressing the LAST ERROR button

There are no error codes stored in the control board's memory. This is what the board answers when the LAST ERROR button is pressed and the fault history is empty.

Manual wording: “If there are no error codes in memory, the LED will flash two green flashes.”

Documented for: All UPG boards with a LAST ERROR button

Likely causes, most common first

  1. No stored faults in the control's five-code memory

When to call a technician

Not a fault. If the furnace is still misbehaving with no stored codes, a technician will need to watch it through a full cycle.

A York furnace throwing this code repeatedly has a reason — clearing the code without fixing the cause just hides it.

Sources

Full page for York code 2 green flashes

Code 2 amber flashes (YP9C modulating): Normal operation with a call for heat

StatusShown as: Two amber flashes, two-second pause, repeating

Normal operation with a call for heat. Not a fault.

Manual wording: “Two Amber Flashes - Normal operation with call for heat.”

Documented for: YP9C, YPLC modulating furnaces

Likely causes, most common first

  1. Normal heating operation

When to call a technician

No service needed.

A York furnace throwing this code repeatedly has a reason — clearing the code without fixing the cause just hides it.

Source

Full page for York code 2 amber flashes (YP9C modulating)

Code 2 red flashes (YP9C modulating): The pressure switch is closed while inducer pressure is below the switch setpoint - the switch is closed when it should be open, so the control will not start

Soft lockoutShown as: Two red flashes, two-second pause, repeating

The pressure switch is closed while inducer pressure is below the switch setpoint - the switch is closed when it should be open, so the control will not start.

Manual wording: “Two Red Flashes - Pressure switch closed with inducer pressure below pressure switch setpoint (switch is closed when it should be open). Check pressure switch and pressure transducer.”

Documented for: YP9C, YPLC modulating furnaces

Likely causes, most common first

  1. Faulty pressure switch stuck closed
  2. Faulty pressure transducer

What you can safely check yourself

  • Turn the furnace off at the service switch for a minute and back on once to see whether the code clears

When to call a technician

A stuck pressure switch is a safety interlock failure. It must be tested and replaced by a technician - never jumper it.

A York furnace throwing this code repeatedly has a reason — clearing the code without fixing the cause just hides it.

Source

Full page for York code 2 red flashes (YP9C modulating)

Code 2 green flashes (YP9C modulating): Indicator for 'No error codes in memory'

StatusShown as: Two green flashes after pressing the LAST ERROR button

Indicator for 'No error codes in memory'. Not a fault.

Manual wording: “Two Green Flashes - Indicator for "No error codes in memory".”

Documented for: YP9C, YPLC modulating furnaces

Likely causes, most common first

  1. No stored faults in the control's five-code memory

When to call a technician

Not a fault. Johnson Controls states only a qualified service technician should use the fault-history feature.

A York furnace throwing this code repeatedly has a reason — clearing the code without fixing the cause just hides it.

Source

Full page for York code 2 green flashes (YP9C modulating)

Other York codes