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KB Home / Equipment / Package Units / York / PG3 / PG3 - Status/Diagnostic Codes

PG3 - Status/Diagnostic Codes

Article ID: 781
Last updated: 3 Dec, 2025

York Package Unit: PG3

Re: Status Codes / Diagnostic Codes

These York package units have a control board inside the unit control compartment that will flash a diagnostic code that shows the operating status of the unit.

Status/Diagnostic Codes
Status LED A2L LED Condition Solution
Slow Green Off Normal Operation - no calls from thermostat
Rapid Green Off Indicates the single-stage DSI control board is in factory test mode
Slow Amber Off Normal Operation - with a call for HEATING
Rapid Amber Off Low flame signal
  • Flame signal below 1.5 microamps
  • Check flame sensor
  • Check gas pressure
4 Amber Off No Call for G
  • Check low voltage wiring
1 Red Off Flame sensed with gas valve off
  • Stuck gas valve
  • Shorted flame sensor 
  • Faulty control
2 Red Off Pressure switch stuck closed
  • Bad pressure switch
  • Inducer fan relay stuck on
3 Red Off Pressure switch stuck open
  • Bad pressure switch
  • Bad inducer fan
  • Bad inducer fan relay
  • Blocked or restricted vent
  • Condensate drainage issue
4 Red Off Limit switch open / open fuse
  • Bad limit
  • Low airflow
  • Over-Fired
5 Red Off Limit circuit open more than 15min / Tripped rollout
  • Bad switch
  • Cracked heat exchanger
  • Bad inducer motor
  • Over-Fired
6 Red Off

4 open pressure switch faults in one heating cycle
  • Bad pressure switch
  • Bad inducer fan
  • Bad inducer fan relay
  • Blocked or restricted vent
  • Condensate drainage issue
7 Red Off 3 failed ignition attempts
  • Bad igniter
  • Dirty flame sensor
  • No gas flow
8 Red Off Flame was established but later lost - 5 times in one heating cycle
  • Dirty flame sensor
  • Combustion air problem
9 Red Off Grounding or line polarity fault
  • Look for loose or missing Ground wire
  • Try reversing transformer power
10 Red Off Gas valve circuit shorted
  • Check gas valve wiring
11 Red Off Limit circuit open between 5-15min
  • Bad limit
  • Blower failure
4 & 5 Ton Models with A2L Sensor
Rapid Red On Indicates an A2L refrigerant leakage or potentially gas leakage
  • Owner to notify service personnel as soon as possible. Maintain power to the unit and try to keep the house ventilated by opening windows if possible.
  • Service personnel to locate refrigerant leak point(s) and repair. Adjust unit charge and get unit back to proper functions.
  • Note: There is potential for the A2L sensor to detect gas or propane leakage. If the service person can not find refrigerant leakage, check on gas pipe leaks and other gas heat components for leakage. Change to new parts after you confirm gas heat component leak(s).
1 Red On Occurs only on power up. Indicates the A2L sensor is not connected to the A2L terminal of the single-stage DSI control board
  • Ensure the correct A2L sensor is properly plugged in the A2L terminal of the single-stage DSI control board.
  • Ensure the A2L sensor cable is not damaged.
2 Red On ndicates the A2L sensor is not connected to the A2L terminal of the single-stage DSI control board
  • Ensure the correct A2L sensor is properly plugged in the A2L terminal of the single-stage DSI control board.
  • Ensure the A2L sensor cable is not damaged.
3 Red On Indicates the A2L sensor may have failed or broken
  • Replace to a new part, and ensure it is the correct A2L sensor.

Fault Code Retrieval:  With no thermostat call push and release the LAST ERROR button.  The LED will flash up to 5 stored fault codes, beginning with the most recent.  If there are no codes in memory, the LED will flash two green flashes.

Clear the Fault Codes:  Push and hold the LAST ERROR button for at least five seconds.  The LED will flash three green flashes when the memory has been cleared.

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Article ID: 781
Last updated: 3 Dec, 2025
Revision: 9
Access: Public
Views: 0
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