Goodman Heat Pump Error Codes

Updated October 13, 2026 · by Aurora Star Tech Inc.

44 Goodman Heat Pump error codes and diagnostic codes, with causes and troubleshooting steps for each. Select a code, or find your model below.

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Goodman Heat Pump error codes list

Code	Meaning	Severity
01	Low side fault or low pressure switch trip	High
02	High side fault or high pressure switch trip	High
03	Short cycling	Medium
04	Locked rotor	Critical
05	Open circuit - compressor off over 4 hours	High
06	Open start circuit	Critical
07	Open run circuit	Critical
08	No line voltage	High
09	Low 24 V control voltage	Medium
A2	Outdoor air temperature sensor fault	Medium
A3	Outdoor coil temperature sensor fault	High
b0	Indoor blower not running when it should be	High
b9	Indoor airflow lower than requested	Medium
CoreSense 1	Yellow 1 flash - long run time (low side)	Medium
CoreSense 2	Pressure trip - yellow 2 flashes (red 2 = lockout)	High
CoreSense 3	Short cycling / pressure switch cycling - yellow 3 (red 3 = lockout)	Medium
CoreSense 4	Locked rotor - yellow 4 (red 4 = lockout)	Critical
CoreSense 5	Moderate run trip - yellow 5 (red 5 = lockout)	High
CoreSense 9	Red 9 flashes - PROT output overcurrent	High
CoreSense solid red	Solid red TRIP - call present but compressor not running	High
d0	No shared data on the network	High
d1	Invalid shared data on the network	High
d2	System mismatch - indoor unit cannot supply required airflow	Medium
d3	Configuration mismatch - shared data does not match hardware	High
d4	Shared data from the loader rejected	High
E5	Outdoor control low-voltage fuse open	High
EE	Outdoor control fault - compressor relay contacts welded	High
H8	High line voltage	High
L1	Lockout - low pressure switch tripped 3 times	High
L2	Lockout - high pressure switch tripped 3 times	High
L6	Lockout - open start circuit detected 4 times	Critical
L7	Lockout - open run circuit detected 4 times	Critical
L8	Low line voltage	High
P0	Compressor protector open	High
Yellow 1 flash	Low side fault / low pressure trip / low pressure lockout (older ComfortNet board)	High
Yellow 2 flashes	High side fault / high pressure trip / high pressure lockout (older ComfortNet board)	High
Yellow 3 flashes	Short cycling (older ComfortNet board)	Medium
Yellow 4 flashes	Locked rotor (older ComfortNet board)	Critical
Yellow 5 flashes	Open circuit (older ComfortNet board)	High
Yellow 6 flashes	Open start circuit / lockout (older ComfortNet board)	Critical
Yellow 7 flashes	Open run circuit / lockout (older ComfortNet board)	Critical
Yellow 8 flashes	Low or high line voltage (older ComfortNet board)	High
Yellow 9 flashes	Low 24 V control voltage (older ComfortNet board)	Medium
Yellow ON + Red ON	Compressor protector open (older ComfortNet board)	High

Find codes by Goodman model

Heat Pump troubleshooting guides

No heat - R-32 GLZS/ALZS heat pump Goodman · Heat Pump
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Reversing valve not shifting - ComfortNet heat pumps Goodman · Heat Pump

Homeowner help: AC Running But Not Cooling: What to Check · Heat Pump Not Heating or Blowing Cold Air

General guidance for qualified technicians. The manufacturer's installation and service manual and local codes always take priority. Aurora Star Tech is not affiliated with, endorsed by or sponsored by any equipment manufacturer; brand and model names are used only to identify equipment and belong to their owners.

Goodman Heat Pump error codes list

Find codes by Goodman model

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