Lennox Error Code 71517: Indoor fan motor failure (Air Handler)

Updated October 13, 2026 · by Aurora Star Tech Inc.

Lennox error code 71517 on a air handler means: Indoor fan motor failure. It is also called Lennox diagnostic code 71517.

High severityAir HandlerAlso Furnace

Homeowner? What Lennox code 71517 means for you

Call a technician Your air handler is reporting: Indoor fan motor failure. The air handler has locked out or cannot run properly. One reset is fine; if the code comes back, it needs a licensed technician to find the cause.

Safe things you can check yourself

Check the thermostat: right mode (Heat or Cool), set a few degrees past room temperature, and fresh batteries if it uses them.
Make sure the unit has power: its on/off switch (often looks like a light switch near the unit) is ON and the breaker in the electrical panel is not tripped.
Look at the air filter. If it is grey and clogged, replace it; a blocked filter causes many shutdowns.
Try one reset: turn the power off for 30 seconds, then back on. If the code comes back, stop resetting and call a technician.

Call (647) 657-2977 Book a service call

Licensed technicians serving Vaughan, Toronto and the GTA.

What does Lennox error code 71517 mean?

Superheat/suction pressure values outside expected range. (S40 system diagnostics) S30/S40 thermostat alert code 71517.

Applies to: Lennox communicating air handlers and EIM-equipped indoor units in S30/S40 smart thermostat systems

Common causes of Lennox code 71517

See description

Safety: Gas, electrical and refrigerant work must be done by a licensed technician. Turn off power and gas before servicing, never bypass a safety control, and always follow the manufacturer's manual for your exact model.

Other Lennox Air Handler codes

Code	Meaning
545	Zone 4 temperature sensor fault
546	Zone sensor parameters reset after power restore
547	Zone sensor parameters reset from system interruption
548	Zone humidity sensor error
551	Zone sensor lost communication
71511	Duct or filter blockage
E105	Wiring issue / communication problem
E114	AC line frequency / distortion problem
E115	Low secondary (24 VAC) voltage
E116	High secondary (24 VAC) voltage
E117	Poor ground
E120	Unresponsive device

All Lennox Air Handler error codes →

Lennox code 71517: homeowner questions

What does Lennox code 71517 mean?

Indoor fan motor failure. Superheat/suction pressure values outside expected range. (S40 system diagnostics) S30/S40 thermostat alert code 71517.

Is it safe to keep using my air handler with code 71517?

It depends on the cause. The air handler has locked out or cannot run properly. One reset is fine; if the code comes back, it needs a licensed technician to find the cause.

Can I reset Lennox code 71517 myself?

You can try one reset (power off for 30 seconds, then on). If Lennox code 71517 comes back, the cause is still there and a licensed technician should check it.

Who can fix Lennox code 71517 near me?

Aurora Star Tech Inc. repairs Lennox air handlers in Vaughan, Toronto and across the GTA. Call (647) 657-2977 or book a service call online.

Troubleshooting guides

Two horizontal lines on display (soft disable) - Lennox communicating Lennox · Air Handler

Source: Lennox Residential Communicating Systems Alert Code Guide (V2) 100017 (3/2023), Table 2 Alert Codes and Troubleshooting, p.50. Written in our own words as a summary; always check the original manual.

General guidance for qualified technicians. The manufacturer's installation and service manual and local codes always take priority. Aurora Star Tech is not affiliated with, endorsed by or sponsored by any equipment manufacturer; brand and model names are used only to identify equipment and belong to their owners.