Furnace Error Code Lookup

Find your furnace brand and model to look up error codes, causes, and fixes.

How Furnace Error Codes Work

When your furnace detects a problem, it displays an error code using LED lights on the control board. You can see them through the small viewing window on the front panel.

Important: error codes are different for each manufacturer. The same blinking pattern can mean completely different things on a Carrier vs. a Lennox. Some brands use blink counts, others use two-LED systems, and Lennox uses alphanumeric codes like E200. To look up your code, you need to know your furnace's brand and model number first.

Select Your Brand

Amana 4 models American Standard 2 models Bryant 3 models Carrier 4 models Coleman 1 model Goodman 5 models Lennox 2 models Payne 4 models Rheem 4 models Ruud 4 models Trane 2 models York 2 models

Commonly Searched Error Codes

Jump straight to a frequently looked-up furnace error code. Each guide covers the causes, whether it's a DIY fix, and when to call a pro.

Browse all brands & models →

Most Common Furnace Error Codes

While codes vary by brand, these issues come up most often across all furnace types:

Ignition failure — The furnace tries to light but can't sustain a flame. Usually a dirty flame sensor, which is a quick DIY fix.
Pressure switch fault — The furnace can't verify proper venting. Often caused by a blocked exhaust pipe or condensation in the pressure tube.
Limit switch lockout — The furnace overheated and shut down. Typically from a clogged filter or blocked vents restricting airflow.
Blower motor fault — The blower isn't running or is running at the wrong speed. Usually requires professional repair.

Find the exact code for your model by selecting your brand above.

DIY vs. Professional Repair

Some furnace problems are simple enough to fix yourself. Others require a licensed HVAC technician.

Safe to DIY

Replace or clean the air filter
Clean the flame sensor
Check and open blocked vents
Reset the furnace at the breaker
Check thermostat settings and batteries

Typical cost: $0 – $30 (parts only)

Call a Professional

Gas valve replacement
Control board replacement
Electrical wiring issues
Heat exchanger inspection
Any issue involving gas lines

Typical cost: $75 – $600+ (diagnosis + parts + labor)

Emergency Warning Signs

Stop troubleshooting and take action immediately if you notice:

Gas smell — Leave the house, do not flip any switches, call your gas company from outside
Carbon monoxide detector alarm — Evacuate immediately, call 911
Visible flames outside the burner area — Turn off the furnace and call an HVAC technician
Burning smell or smoke — Turn off the furnace at the breaker and call for service