ICP Error Codes & Diagnostic Codes

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

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

ICP error codes by equipment type

ICP Furnace error codes

Code	Meaning
1+2	Blower on after power-up (normal)
1+5	Blower motor lockout
2	Pressure switch did not open
2+5	Invalid model selection or setup error
3	Low pressure switch did not close or reopened
3+5	Gas valve fault (modulating valve)
4	Limit circuit fault
4+1	Blower motor fault
4+2	Inducer motor fault
4+3	Low/medium pressure switch open while medium/high switch closed
5	Abnormal flame-proving signal
6	Ignition proving failure
6+1	Ignition lockout
7	Limit circuit lockout
8	Gas heating lockout
9	Medium/high pressure switch or PSR relay did not close or reopened
10	Line voltage polarity
LED off	Amber status LED off - no power / blown 3 A fuse
LED steady ON	Amber LED on solid - control lockout / wrong model plug

ICP Heat Pump error codes

Code	Meaning
1	Long run time
2	System pressure trip
3	Short cycling
4	Locked rotor
5	Open circuit
6	Open start circuit
7	Open run circuit
8	Welded contactor
9	Low voltage
Red TRIP LED	Comfort Alert TRIP - Y1 call but compressor not running
TRIP + ALERT flashing together	Control voltage too low

Find codes by ICP model

ICP (F/G)9MAE Modulating Furnace

G9MAE0601714 G9MAE0602120 G9MAE0801714 G9MAE0802120 G9MAE1002122 G9MAE1202422

ICP N4H3 Heat Pump

N4H3

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.