Carrier furnace codes
A furnace reports faults on a small status LED on the control board, seen through the sight glass in the blower door, or on a two-digit display. Watch a full cycle of the pattern and count the flashes, including the pause between groups, before you decide what you saw. The code chart is on the label inside the blower door.
Models covered: 58STA, 58STX.
All 15 codes
Continuous OffNo power to the control board (LED stays dark) (pro repair)Continuous OnNormal: control board has 24 volt power (LED steady on) (DIY)Rapid FlashingLine voltage polarity reversed (LED flashing rapidly) (pro repair)11No previous fault code stored (DIY)12Blower on after power up (DIY)13Limit circuit lockout (pro repair)14Ignition lockout (pro repair)21Gas heating lockout (pro repair)22Abnormal flame-proving signal (flame sensed with gas valve off) (pro repair)23Pressure switch did not open (pro repair)24Secondary voltage fuse is open (DIY)31Pressure switch did not close or reopened (pro repair)33Limit circuit fault (pro repair)34Ignition proving failure (pro repair)45Control circuitry lockout (pro repair)
About Carrier codes
This page lists the fault codes this brand documents, with likely causes and a short repair path. The codes apply to model numbers such as 58STA and 58STX; check the label on your unit to confirm yours.