Carrier Error Code and Repair Guides - 72 Guides
Carrier HVAC troubleshooting hub with 72 guides for fault codes, alarms, symptoms, parts checks, and repair decisions.
Use this page when your Carrier furnace, air conditioner, heat pump, or mini split is flashing a fault. Start with the exact code, then open the fix guide to diagnose airflow, ignition, sensor, pressure switch, board, or communication problems before you order parts or book a service call.
Tip: search the exact brand, model, and code together, for example "Carrier error code 13" or "Carrier pressure switch fault".
Start With These Carrier Guides
Carrier 31 Error Code — Pressure Switch Fix Carrier 31 pressure-switch guide for inducer draft, hoses, condensate traps, vent blockages, manometer checks, and part decisions. Carrier Chiller Alarm Codes - 30XA, 30XV, 30HXC, 19XR Carrier chiller alarm guide for 30XA, 30XV, 30HXC, and 19XR units: ComfortLink history, pressure trips, sensors, oil, and resets. Carrier Geothermal Error Codes - Low Pressure, Freeze, ECM Decode Carrier geothermal low-pressure, high-pressure, freeze protection, condensate, ECM blower, water-temperature, and Infinity communication faults. Carrier Infinity Error 178 - Indoor to Outdoor Communication Fault Carrier Infinity 178 means the indoor and outdoor units lost communication. Check low-voltage wiring, terminals, boards, and data-line continuity. Carrier Rooftop Unit Error Codes Carrier RTU guide for 48 and 50 Series flash codes, ignition lockouts, limit trips, pressure faults, economizer alarms, and control-board checks. Carrier VRF System Error Codes Guide Carrier VRF error codes point to EEV, thermistor, compressor, pressure, communication, drain, and controller faults.
Carrier FAQ
Where should I start with Carrier error codes?
Start with the exact Carrier model and displayed code or alarm, then open the closest guide on this page. Match the symptom, recent service history, and any secondary codes before resetting the equipment or ordering parts.
Do Carrier fault codes always mean a bad control board?
No. Many Carrier codes point to airflow, water flow, sensors, wiring, power quality, filters, switches, or operating conditions. Check the simple causes in the guide before replacing an expensive board.
When should I stop troubleshooting a Carrier fault myself?
Carrier HVAC equipment can hide unsafe ignition, refrigerant, high-voltage, or combustion problems behind a simple blinking code. Stop and use the repair checklist or compare service options when the guide points to gas, refrigerant, line voltage, sealed-system work, food-safety temperatures, or repeated faults after a reset.
| Error Code | What It Means | Guide |
|---|---|---|
| Carrier 31 Error Code | Pressure Switch Fix | Fix → |
| Carrier Chiller Alarm Codes | 30XA, 30XV, 30HXC, 19XR | Fix → |
| Carrier Geothermal Error Codes | Low Pressure, Freeze, ECM | Fix → |
| Carrier Infinity Error 178 | Indoor to Outdoor Communication Fault | Fix → |
| Carrier Rooftop Unit Error Codes | Carrier RTU guide for 48 and 50 Series flash codes, ignition lockouts, limit trips, pressure faults, economizer alarms, and control-board checks. | Fix → |
| Carrier VRF System Error Codes Guide | Carrier VRF error codes point to EEV, thermistor, compressor, pressure, communication, drain, and controller faults. | Fix → |
| Carrier Infinity Error 168 | Carrier Infinity 168 guide for system communication faults, ABCD bus wiring, thermostats, furnace boards, outdoor boards, and setup checks. | Fix → |
| Carrier 30XA Chiller Fault Codes | Carrier 30XA chiller fault guide for air-cooled alarms, pressure faults, flow trips, sensors, compressors, fans, and controls. | Fix → |
| Carrier 58MVB Furnace Error Codes | Carrier 58MVB furnace flash-code guide for pressure switch, limit, flame-sense, inducer, igniter, ECM blower, and gas-valve faults. | Fix → |
| Carrier 13 Error Code | Limit Switch Lockout Fix | Fix → |
| Carrier 21 Error Code | Gas Heating Lockout Fix | Fix → |
| Carrier Furnace Error Code 13 Limit Lockout | Carrier code 13 guide for limit-switch lockout, overheating, airflow restrictions, code 33 differences, blower checks, filters, and safety limits. | Fix → |
| Carrier 24ANA Heat Pump Error Codes | Carrier 24ANA heat-pump fault guide for Performance Series LED codes, pressure trips, defrost faults, sensors, and board checks. | Fix → |
| Carrier 54 Error Code | Low Pressure Switch Soft Lockout | Fix → |
| Carrier AquaSnap Chiller Fault Codes | 30RB/30RQ Guide | Fix → |
| Carrier Infinity Error 179 Communication Fault | Carrier Infinity 179 guide for lost equipment communication, ABCD bus wiring, thermostat faults, furnace boards, fuses, and outdoor unit checks. | Fix → |
| Carrier 34 Error Code | Ignition Proving Failure | Fix → |
| Carrier Furnace Error Codes | Complete Guide | Fix → |
| Carrier Greenspeed Heat Pump Error Codes: Complete Guide | Carrier Greenspeed variable speed heat pump error codes and fault diagnostics. Infinity system fault codes, causes, and technician fixes. | Fix → |
| Carrier Infinity Zoning System Error Codes | Complete Guide | Fix → |
| Carrier WeatherMaker Rooftop Unit Error Codes: Complete Guide | Carrier WeatherMaker RTU error codes for 48 and 50 Series commercial rooftop units. Flash codes, fault descriptions, and technician-level fixes. | Fix → |
| Carrier Zone Controller Error Codes | Complete Guide | Fix → |
| Carrier 11 Error Code | No Ignition Furnace Lockout | Fix → |
| Carrier 12 Error Code | Blower Runs After Heat | Fix → |
| Carrier 13 Soft Lockout | What's Different from Hard Lockout | Fix → |
| Carrier 14 Error Code | Ignition Lockout | Fix → |
| Carrier 22 Error Code | LSOM Stall Fault on Single-Stage Furnaces | Fix → |
| Carrier 23 Error Code | Draft Safeguard Switch Fault | Fix → |
| Carrier 24 Error Code | Secondary Voltage Fuse Open | Fix → |
| Carrier 24ACC Air Conditioner Error Codes | Carrier 24ACC guide for AC flash codes, high- and low-pressure trips, compressor protection, thermistors, contactors, and board checks. | Fix → |
| Carrier 25 Error Code | Flame Sense Fault | Fix → |
| Carrier 32 Error Code | Pressure Switch Stuck Closed | Fix → |
| Carrier 33 Error Code | Limit Switch Open | Fix → |
| Carrier 40MAQ / 40MVC Mini Split Error Codes | Communication, Sensor, and Protection Faults | Fix → |
| Carrier 41 Error Code | Blower Motor Fault Fix | Fix → |
| Carrier 42 Error Code | Inducer Motor Fault | Fix → |
| Carrier 43 Error Code | Rollout Switch Open Fix | Fix → |
| Carrier 44 Error Code | Open Igniter Circuit | Fix → |
| Carrier 45 Error Code | IFC Control Board Fault | Fix → |
| Carrier 46 Error Code | IFC Board Self-Diagnosis Fault | Fix → |
| Carrier 48 Error Code | Induced Draft Motor Lockout | Fix → |
| Carrier 48XLC Packaged Unit Error Codes | Carrier 48XLC packaged-unit fault guide for pressure trips, ignition faults, economizer issues, sensors, airflow, and board checks. | Fix → |
| Carrier 52 Error Code | Repeated High-Limit Soft Lockout | Fix → |
| Carrier 56 Error Code | Induced Draft IFC Fault | Fix → |
| Carrier 58 Error Code | Flame Sense Fault | Fix → |
| Carrier 58CVA Furnace Error Codes | Carrier 58CVA furnace guide for flash codes, pressure switches, ignition lockouts, limit trips, flame sensing, inducer faults, and resets. | Fix → |
| Carrier 58UX Furnace Error Codes | Carrier 58UX furnace guide for LED flash codes, pressure switches, limit trips, flame-sense faults, polarity errors, and lockouts. | Fix → |
| Carrier AC E3 Error Code: IPM Module Fault Diagnosis and Fix | Carrier E3 points to an IPM fault. Check condenser airflow, voltage, refrigerant charge, compressor windings, and board damage before replacement. | Fix → |
| Carrier Code 33 Limit or Rollout Fault | Carrier code 33 guide for limit-switch and rollout faults, airflow, filters, blower speed, gas pressure, heat exchangers, and resets. | Fix → |
| Carrier E3 Error Code | Inverter Heat Protection Fault | Fix → |
| Carrier Error Code 24 | Secondary Voltage Fuse Open | Fix → |
| Carrier Error Code 51 | Control Fault (Secondary) | Fix → |
| Carrier Error Code 61 | Rollout Switch Lockout | Fix → |
| Carrier Error Code 65 | Inducer Motor Fault | Fix → |
| Carrier Error Code 66 | Pressure Switch Fault | Fix → |
| Carrier Furnace E1 Error Code | Infinity Communication Fault | Fix → |
| Carrier Furnace Error Code 13 | Limit Circuit Lockout Fix | Fix → |
| Carrier Furnace Error Code 31 | Pressure Switch Open Fix | Fix → |
| Carrier Heat Pump E1 Error Code | Causes & Fix | Fix → |
| Carrier Heat Pump E4 Error Code | Causes & Fix | Fix → |
| Carrier Heat Pump E5 Error Code | Defrost Fault: Causes & Fix | Fix → |
| Carrier Heat Pump E6 Error Code | Outdoor Temp Sensor Fault | Fix → |
| Carrier Infinity 24ACC6 Error Codes | Carrier Infinity 24ACC6 guide for pressure trips, thermistors, compressor protection, discharge sensors, communication faults, and board checks. | Fix → |
| Carrier Infinity Communication Error Codes | Carrier Infinity communication codes point to thermostat, indoor unit, outdoor unit, or bus faults. Check ABCD wiring, module power, and zoning. | Fix → |
| Carrier Infinity XC21 Error Codes | Carrier Infinity XC21 guide for low-pressure, high-pressure, communication, compressor-protection, outdoor fan, thermistor, and lockout faults. | Fix → |
| Carrier Mini-Split E4 Discharge Temp Fault | Carrier mini-split E4 guide for compressor discharge temperature faults, refrigerant issues, dirty coils, fan problems, and thermistor checks. | Fix → |
| Carrier Mini-Split F0 Low Refrigerant Code | Carrier mini-split F0 guide for low refrigerant and leak-detection faults, shutdown steps, leak checks, pressure sensors, and HVAC technician repair. | Fix → |
| Carrier Mini-Split P4 Inverter Overheat | Carrier mini-split P4 means the inverter module overheated. Check coil airflow, outdoor fan, clearance, heat sink, wiring, and board faults. | Fix → |
| Bryant Furnace Error Codes | Bryant furnace code guide for LED flashes, two-digit faults, Evolution diagnostics, Carrier-shared boards, ignition, limit, and pressure-switch checks. | Fix → |
| Best Furnace Igniter Replacement: Universal and Brand-Specific Picks | Choose a furnace igniter replacement by matching style, voltage, bracket, and brand fit before ordering a universal or OEM part. | Fix → |
| Furnace Blinking 3 Times | Cross-Brand Comparison Guide | Fix → |
| How to Reset a Furnace After Lockout | Per-Brand Reset Procedures | Fix → |