Which models this covers
Carrier 58CVA/58CVX variable-speed two-stage gas furnaces (Troubleshooting Guide TG-GFC80-02). Ultra-low-NOx models (58SU0A) use a different table. Bryant furnaces are Carrier-built, but we didn’t find a Bryant-branded chart to confirm. Codes differ between control boards, so check the code chart printed on your unit or in its manual if your model isn’t listed.
How to read the code
Look through the sight glass on the blower door. Count the short flashes (first digit), then the long flashes (second digit). Steady on means normal 24V power. Off means no power. Very rapid flashing means 115V polarity is reversed.
Status codes (58CVA/58CVX)
| Code | What it means | What to do |
|---|---|---|
| 11 | No previous code stored | None. |
| 12 | Blower ran after power-up | None. This is normal after a power interruption. |
| 13 | Limit circuit lockout (limit open over 3 minutes, or 10 trips) | Check for a dirty filter and closed or blocked vents. It auto-resets after 3 hours. If it repeats, call a pro.Pro |
| 14 | Ignition lockout (see code 34) | Make sure the gas is on. It auto-resets after 3 hours. If it repeats, call a pro.Pro |
| 15 | Blower motor lockout | Call a pro.Pro |
| 21 | Gas heating lockout (no auto-reset) | Call a pro.Pro |
| 22 | Flame proved with gas valve off (leaky or stuck gas valve) | Turn off the furnace and gas. Call a pro urgently.Pro |
| 23 | Pressure switch didn’t open | Call a pro.Pro |
| 24 | 24V fuse open (short in low-voltage wiring) | Call a pro.Pro |
| 25 | Model plug or setup error | Call a pro.Pro |
| 31 / 32 | High-heat / low-heat pressure switch didn’t close (venting, inducer or wind) | Check outside vent pipes for snow, ice or blockage. If clear, call a pro.Pro |
| 33 | Limit circuit fault | Replace a dirty filter and open blocked vents or registers. If a rollout switch tripped, call a pro.Pro |
| 34 | Ignition proving failure | Check that the manual gas valve is on and gas service is on. If so, call a pro (often the flame sensor).Pro |
| 41 | Blower motor fault | Call a pro.Pro |
| 43 | Low-heat pressure switch open while high-heat switch closed | Call a pro.Pro |
| 45 | Control circuitry lockout | Turn power off and on to reset. If it repeats, call a pro (the board may need replacing).Pro |
Sources
These codes are transcribed from the manufacturer’s own documentation. Many websites repeat codes that don’t match the manuals, so when in doubt, trust the chart on your unit.
- Carrier Troubleshooting Guide TG-GFC80-02 (58CVA/58CVX)
- Carrier Ultra-Low NOx troubleshooting guide (different codes)
Code pointing to a big repair? Check whether to repair or replace before you pay for it.
Frequently asked questions
What does code 33 mean on a Carrier furnace?
Code 33 is a limit circuit fault: the furnace got too hot and the safety limit opened. The most common homeowner-fixable causes are a dirty air filter and closed or blocked supply vents and return grilles. If it continues, or a rollout switch tripped, call a pro.
What does code 34 mean on a Carrier furnace?
Code 34 is an ignition proving failure: the furnace tried to light but didn’t sense flame. First check that the gas valve at the furnace is on and your gas service is on. If so, a technician should check the flame sensor and ignition.
How do I reset a Carrier furnace code?
Many lockouts (13, 14) reset automatically after 3 hours. You can also turn the furnace power switch off for 10 seconds and back on. If the same code returns, there’s an underlying problem to fix.