Goodman Error Codes & Diagnostic Codes

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

Goodman error codes and diagnostic codes: look up a code to see what it means, the likely causes and the steps to fix it.

Goodman error codes by equipment type

Goodman Air Conditioner error codes

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

Goodman Air Handler error codes

Code	Meaning
E0F	Condensate switch open - high water in drain pan
E05	Air handler fuse open
Eb0	Blower motor not running with a demand present
Eb1	Control lost communication with the blower motor
Eb2	Motor horsepower does not match shared data
Eb3	Blower limiting on power, temperature or speed
Eb4	Blower motor lost rotor control or high current
Eb5	Blower motor failed to start 10 times
Eb6	Blower shut down for voltage or power module temperature
Eb7	Blower motor missing shared data / failed to start 40 times
Eb9	Airflow lower than demanded
EC1	Communication error with the outdoor unit
Ed0	No shared data on the network
Ed1	Invalid shared data
Ed4	Shared data rejected by the control
RDS 2 flashes	Control board internal fault (leak detection board)
RDS 3 flashes	R32 sensor communication fault
RDS 4 flashes	R32 sensor internal fault
RDS fast flash	R-32 leak alarm (or system verification test)
RDS steady on	Delay mode after leak alarm or fault

Goodman Furnace error codes

Code	Meaning
E10	Grounding fault / poor neutral connection
E11	Flame rollout switch open
EE0	Lockout - too many ignition retries (3)
EE1	Pressure switch closed at start of heating cycle
EE2	Pressure switch did not close (inducer runs, no ignition)
EE3	High (primary) limit open
EE4	Flame sensed with no call for heat
EE5	Open fuse (short in low voltage wiring)
EE6	Low flame signal
EE8	High-stage pressure switch closed at start of heating cycle
EE9	High-stage pressure switch did not close
EEA	Reversed line polarity or grounding error
EEb	External gas valve error - valve not energized when it should be
EEC	Internal gas valve error - valve energized when it should not be
EEE	Internal control fault (IRQ loss)
EEH	Twinning error
EEJ	Inducer relay error
EEL	Igniter relay / igniter circuit fault
EEn	Igniter open

Goodman Heat Pump error codes

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

Find codes by Goodman model

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 error codes by equipment type

Goodman Air Conditioner error codes

Goodman Air Handler error codes

Goodman Furnace error codes

Goodman Heat Pump error codes

Find codes by Goodman model

Goodman/Amana GM9C96/AM9C96

Goodman/Amana GM9S80/AM9S80

Goodman/Amana GM9S96/AM9S96

Goodman/Amana R-32 AMST/AWSF/ACSF air handlers

Goodman/Amana R-32 GLXS/ALXS

Goodman/Amana R-32 GLZS/ALZS

Goodman/Amana R-410A GSX/ASX/DSX (ANX/SSX/VSX)

Goodman/Amana R-410A GSZ/ASZ/DSZ (ANZ/SSZ/VSZ)

Goodman/Amana ComfortNet ASXC/GSXC/DSXC

Goodman/Amana ComfortNet ASZC/GSZC/DSZC

Goodman/Amana ComfortBridge AVPTC/MBVC

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