Quick answer: Trane and American Standard furnaces use the same control boards. On most models, 2 blinks is an ignition lockout, 3 blinks is a pressure switch fault, 4 blinks is an open high limit or rollout switch, 5 blinks is flame sensed with the gas valve off, 6 blinks is a polarity or grounding problem, and 7 blinks is a gas valve circuit fault. A slow, steady blink is normal. Some newer models use two-digit codes, so check the label on your blower door.
Safety first: if you smell gas, do not reset or relight anything. Leave the home and call your gas utility (Nicor Gas 1-888-642-6748, or North Shore Gas 1-866-556-6005) or 911 from outside.
Trane and American Standard Blink Code Chart
| Blinks | Typical meaning | Common causes |
|---|---|---|
| Slow steady blink | Normal operation | No fault |
| Off or solid | No power or control fault | Switch off, breaker, fuse, door switch, failed board |
| 2 blinks | Ignition lockout | Dirty flame sensor, igniter, gas supply |
| 3 blinks | Pressure switch fault | Blocked vents, condensate trap, hose, inducer |
| 4 blinks | High limit or rollout switch open | Dirty filter, blower problem, blocked flue |
| 5 blinks | Flame sensed with gas valve off | Gas valve leaking through, control fault |
| 6 blinks | Reversed polarity or poor ground | Wiring problem at the furnace |
| 7 blinks | Gas valve circuit fault | Gas valve coil, wiring or control board |
The Trane Codes We See Most
2 blinks: ignition lockout
Usually a dirty flame sensor or a worn igniter. Flame sensor cleaning is $245, and igniter replacement is $305 flat-rate.
3 blinks: pressure switch
Very common in January and February, when snow blocks the PVC vents or condensate freezes. See our pressure switch guide.
4 blinks: limit or rollout
Start with the filter. If a rollout switch is tripping, have the venting and heat exchanger inspected before using the furnace.
Safe Checks Before You Call
- Replace the filter.
- Clear the vent pipes outside.
- Check the condensate drain.
- Reset power once.
What Trane Code Repairs Cost
| Common repair behind a furnace code | Our flat-rate price |
|---|---|
| Flame sensor cleaning and flame signal test | $245 |
| Flame sensor replacement | $275 |
| Hot surface igniter replacement | $305 |
| Pressure switch hose replacement | $250 |
| Pressure switch replacement | $355 |
| High-efficiency condensate trap cleaning or replacement | $290 |
| High limit switch replacement | $340 |
| Flame rollout switch replacement | $325 |
| Flue or PVC vent pipe repair | $435 |
| Inducer motor replacement | $570 to $1,410 |
| Control board replacement | $475 to $1,505 |
| Gas valve replacement | $505 to $1,120 |
| Blower motor replacement | $830 (PSC) to $2,220 (variable speed) |
Prices are flat-rate with parts and labor, as of November 2026. The $75 diagnostic is waived when you approve the repair, and Comfort Club members save 10 to 15% on repairs. Exact pricing depends on your furnace model and whether the part is in stock on our trucks.
Seeing a Trane code in the Northwest Suburbs?
Pure Comfort Heating and Cooling services every major furnace brand from our shop in Streamwood, IL. Diagnostics are $75, or $99 on evenings, weekends and holidays, and the fee is waived when you approve the repair. You approve a flat-rate price before any work starts, and phones are answered 24/7.
Other Error Code Guides
- Furnace blinking light codes by brand
- Lennox furnace error codes
- Carrier, Bryant and Payne furnace codes
- Goodman, Amana and Daikin flash codes
- Furnace pressure switch errors
Frequently Asked Questions
Are Trane and American Standard codes the same?
Yes. Both brands are made by the same company and use the same control boards and blink codes.
What does 3 blinks mean on a Trane furnace?
Three blinks means a pressure switch fault, usually caused by blocked vent pipes, a clogged condensate trap, a cracked hose or a weak inducer.
What does 4 blinks mean?
Four blinks means the high limit or rollout switch opened, usually from restricted airflow such as a dirty filter.
Do you repair Trane and American Standard furnaces?
Yes, throughout the Northwest and West Suburbs, with a $75 diagnostic that is waived when you approve the repair.
We diagnose and repair furnaces from our shop in Streamwood across Streamwood, Bartlett, Hoffman Estates, Schaumburg, Elgin, Hanover Park, Roselle, Arlington Heights and the rest of the Northwest and West Suburbs. See our furnace repair page for flat-rate prices.