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Carrier gas furnace code 19.1: Lost InteliSense communication with the thermostat
Gas furnace, Canada and United States
The control lost InteliSense communication with the thermostat. This fault only shows after InteliSense communication has worked at least once.
This needs a licensed gas technician. There is nothing safe to check yourself. Leave the covers on and book a professional.
Only some models show this code. Check the list below.
What causes it
-
A wiring fault on the R and Y wires between the control and the thermostat.
-
The thermostat is not set up for InteliSense communication.
How to read this code on your unit
The three-digit display sits on the furnace control behind the blower door. Through the sight glass in the door you see only the status light, which flashes the first two digits of the code. Count the short flashes for the first digit, then the long flashes for the second, so 3 short flashes followed by 3 long flashes is a 33.x code. Write down what you see before you open the door or switch the furnace off. The full code with its third digit shows on the control display only with the door removed and the door switch closed, which is a job for a technician. A technician can also look back at the last 7 faults in the FLt menu. Stored codes are erased by themselves after 72 hours of powered operation after the last fault, and the display shows non when no fault is stored.
Booking a licensed gas technician
Book a licensed gas technicianlicensed gas technician
- Turn the unit off and leave the covers on. Gas components must only be serviced by a licensed technician.
- Note the code, how often it appears, and the model and serial numbers from the rating label.
- Book a licensed gas technician and give them those details.
Models that show this code
43 models in 4 ranges
| Range | Models |
|---|---|
| 58SP0B/58SP1B | 58SP0B045V14-12, 58SP0B070V14-12, 58SP0B070V17-16, 58SP0B090V17-16, 58SP0B090V21-20, 58SP0B110V21-22, 58SP0B135V24-22, 58SP1B045V14-12, 58SP1B070V14-12, 58SP1B070V17-16, 58SP1B090V17-16, 58SP1B090V21-20, 58SP1B110V21-22, 58SP1B135V24-22 |
| 58TP0B/58TP1B | 58TP0B045V14-12, 58TP0B070V14-12, 58TP0B070V17-16, 58TP0B090V17-16, 58TP0B090V21-20, 58TP0B110V21-22, 58TP0B135V24-22, 58TP1B045V14-12, 58TP1B070V14-12, 58TP1B070V17-16, 58TP1B090V17-16, 58TP1B090V21-20, 58TP1B110V21-22, 58TP1B135V24-22 |
| 59TP6C | 59TP6C040V14-10, 59TP6C040V17-12, 59TP6C060V14-12, 59TP6C060V17-16, 59TP6C080V17-16, 59TP6C080V21-20, 59TP6C100V21-20, 59TP6C100V21-22, 59TP6C120V24-22 |
| 59TP7A | 59TP7A060V17-16, 59TP7A080V17-16, 59TP7A080V21-20, 59TP7A100V21-20, 59TP7A100V21-22, 59TP7A120V24-22 |
Where this comes from
- 58SP0B gas furnace, installation, start-up, operating and service instructions (58SP0B-01SI) , page 30, 44
- 59TP6C gas furnace, installation, start-up, operating and service instructions (59TP6C-03SI) , page 56, 76
- 58TP0B gas furnace, installation, start-up, operating and service instructions (58TP0B-01SI) , page 32
Checked against the manufacturer's manual on 11 October 2026.
Other Carrier gas furnace codes
| Code | Meaning | What you can do |
|---|---|---|
| 14.2 | Flame lost 3 times after 70 seconds of heating | Safe checks first, then a pro |
| 14.3 | Lockout after 7 flame losses in one heat request | Safe checks first, then a pro |
| 14.4 | Lockout after repeated pressure switch openings | Safe checks first, then a pro |
| 15.1 | Blower lockout, no blower speed signal | Call a pro |
| 15.2 | Blower lockout, blower never reached 500 rpm | Call a pro |
| 17.1 | Lost communication with the Bluetooth module | Call a pro |
| 21.1 | 24 volts sensed at the gas valve when there should be none | Safe checks first, then a pro |
| 22.1 | Flame proved while the gas valve is off | Safe checks first, then a pro |
| 23.1 | Flue or venting fault (depends on model) | Call a pro |
| 23.2 | Secondary pressure switch stuck closed | Call a pro |
| 23.3 | Pressure transducer senses over-pressure | Call a pro |
| 23.4 | Low pressure switch stuck closed | Call a pro |
See all communication fault codes on gas furnaces across brands.