Furnace error codes (page 7)
178 documented codes across brands, with ranked causes and repair costs.
Rheem furnace code chart (13) York furnace code chart (21) Goodman furnace code chart (24) Lennox furnace code chart (34) Trane furnace code chart (23) Carrier furnace code chart (30) Amana furnace code chart (9) American Standard furnace code chart (8) Bryant furnace code chart (16)
Goodman Furnace — 9 flashes Goodman Furnace 9 Flashes: High-Stage Pressure Switch Open Goodman 9 flashes means the high-stage pressure switch didn't close on high fire. Causes, safe checks, technician fixes and honest US costs. Bryant Furnace — Code 21 Bryant Furnace Code 21: Meaning, Causes & Fixes Bryant Code 21 means a gas valve wiring or relay fault on the control board. What it means, safe checks, and realistic 2026 US repair costs. Bryant Furnace — Code 22 Bryant Furnace Code 22: Meaning, Causes & Fixes Bryant Furnace Code 22 means flame is sensed with the gas valve off. Causes, safe checks, and repair costs from $0 DIY to $600+ for a gas valve. Bryant Furnace — Code 23 Bryant Furnace Code 23: Meaning, Causes & Fixes Bryant Code 23 means the pressure switch was stuck closed before the inducer ran. Causes, safe checks, technician fixes and $0–$350 repair costs. Bryant Furnace — Code 31 Bryant Furnace Code 31: Meaning, Causes & Fixes Bryant Furnace Code 31 means the pressure switch didn't prove. Causes, safe checks, fixes and real costs from $0 DIY to $1,200+ for inducer or vent work. Bryant Furnace — Code 34 Bryant Furnace Code 34: Ignition Proving Failure Fixes Bryant Furnace Code 34 means ignition proving failure. Causes: dirty flame sensor, igniter, gas, ground. Fixes and costs from $0 DIY to $400. Bryant Furnace — Code 42 Bryant Furnace Code 42: Inducer Motor Fault Fixes Bryant Furnace Code 42 means an inducer motor fault. Learn causes, safe checks, fixes, and repair costs from $0 DIY to about $1,200 for a new inducer. Bryant Furnace — Code 44 Bryant Furnace Code 44: Blower Calibration Fault Fixes Bryant furnace Code 44 means a variable-speed blower calibration fault. Learn the causes, safe checks, technician fixes and repair costs ($0–$900). Carrier Furnace — Code 12 Carrier Furnace Code 12: Meaning, Causes & Fixes Carrier Furnace Code 12 means power was interrupted during heating. Causes, safe checks, fixes and repair costs for US homeowners. Carrier Furnace — Code 21 Carrier Furnace Code 21: Gas Valve Relay Fault & Fixes Carrier Furnace Code 21 means a gas heating lockout from a shorted valve relay or mis-wired gas valve. Causes, fixes and pro repair costs inside. Carrier Furnace — Code 22 Carrier Furnace Code 22: Abnormal Flame-Proving Signal Carrier Furnace Code 22 means flame is sensed with the gas valve off. Causes, safe checks, technician diagnosis and repair costs explained. Carrier Furnace — Code 23 Carrier Furnace Code 23: Pressure Switch Did Not Open Carrier Furnace Code 23 means the pressure switch stayed closed before the inducer started. Causes, safe checks, fixes & repair costs. Carrier Furnace — Code 24 Carrier Furnace Code 24: Blown Secondary Fuse & Fixes Carrier Furnace Code 24 means the 3A low-voltage fuse is blown from a 24V wiring short. Causes, fixes, and repair costs for US homeowners. Carrier Furnace — Code 32 Carrier Furnace Code 32: Low-Pressure Switch Fault & Fixes Carrier Furnace Code 32 means the low-stage pressure switch did not close or reopened. Causes, fixes and repair costs from $0 DIY to $1,200+. Carrier Furnace — Code 42 Carrier Furnace Code 42: Inducer Motor Fault & Fixes Carrier Furnace Code 42 means an inducer motor fault. Learn the causes, safe checks, technician diagnosis and repair costs from $0 DIY to $1,200. Carrier Furnace — Code 43 Carrier Furnace Code 43: Pressure Switch Calibration Fault Carrier Furnace Code 43 means a pressure switch calibration fault. Causes: venting, tubing, inducer, switch. Fixes and US repair costs inside. Carrier Furnace — Code 44 Carrier Furnace Code 44: Blower Calibration Fault & Fixes Carrier Furnace Code 44 means a blower motor calibration fault on variable-speed boards. Causes, safe checks, fixes and repair costs explained. Carrier Furnace — Code 45 Carrier Furnace Code 45: Control Circuitry Lockout Fix Carrier furnace Code 45 means a control circuitry lockout from flame-sense, software, or gas-valve relay faults. Causes, fixes and repair costs. Goodman Furnace — 1 flashes Goodman Furnace 1 Flash: Ignition Failure Lockout Fixes Goodman furnace 1 flash means ignition failure lockout after 3 failed trials. Causes, safe checks, and repair costs from $0 DIY to $600+. Goodman Furnace — 2 flashes Goodman Furnace 2 Flashes: Pressure Switch Stuck Closed Goodman 2-flash code means the pressure switch is stuck closed. Causes, safe checks, tech diagnosis and repair costs from $0 DIY to $350. Bryant Furnace — Code 12 Bryant Furnace Code 12: Meaning, Causes & Fixes Bryant Furnace Code 12 means a blower call with no power. Causes, safe checks, and repair costs from $0 DIY to $600 for a control board. Bryant Furnace — Code 14 Bryant Furnace Code 14: Meaning, Causes & Fixes Bryant Furnace Code 14 means an ignition lockout. Causes, safe checks, and repair costs ($0 DIY to $600 pro) explained for homeowners. Carrier Furnace — Code 14 Carrier Furnace Code 14: Ignition Lockout Causes & Fixes Carrier Furnace Code 14 means ignition lockout after failed heat trials. Causes, safe checks, technician diagnosis and repair costs $0-$600. Carrier Furnace — Code 41 Carrier Furnace Code 41: Blower Motor Fault & Fixes Carrier Furnace Code 41 signals a blower motor fault. Learn causes, safe checks, diagnosis and repair costs from $0 DIY to $700 for a new motor.