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Lennox Error Code 71001: Wireless extender internal data fault (Furnace)

Updated · by Aurora Star Tech Inc.

Lennox error code 71001 on a furnace means: Wireless extender internal data fault. It is also called Lennox diagnostic code 71001.

Medium severityFurnace

Homeowner? What Lennox code 71001 means for you

Check, then call Your furnace is reporting: Wireless extender internal data fault. This is often caused by something simple. Try the safe checks below; if the code returns, book a service call before it turns into a no-heat or no-hot-water emergency.

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.
  • Make sure the furnace front door or panel is closed properly; many furnaces will not run with the door switch open.
  • Look at the air filter. If it is grey and clogged, replace it; a blocked filter causes many shutdowns.
  • Outside, make sure the intake and exhaust pipes or vent cap are not blocked by snow, ice, leaves or a nest.
  • Check that the gas valve next to the furnace is open (handle in line with the pipe). Do not force it.
  • 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) 657-2977Book a service call

Licensed technicians serving Vaughan, Toronto and the GTA.

What does Lennox error code 71001 mean?

Wireless extender cannot access internal data. S30/S40 thermostat alert code 71001.

Applies to: Lennox communicating gas furnaces (e.g. SL280UHV/SL280UHNV, EL296UHV) in S30/S40 smart thermostat systems

Common causes of Lennox code 71001

  • Extender fault
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.

Lennox models that use code 71001

Show all 38 models

EL195UH040NE36BEL195UH060NE36BEL195UH080NE48CEL195UH100NE60CEL296UH045XV36BEL296UH070XV36BEL296UH090XV36CEL296UH090XV48CEL296UH090XV60CEL296UH110XV48CEL296UH110XV60CEL296UH135XV60DML180UH045E36AKML180UH045XE36AKML180UH070E36AKML180UH070E36BKML180UH070XE36AKML180UH070XE36BKML180UH090E48BKML180UH090E60CKML180UH090XE48BKML180UH110E60CKML180UH110XE60CKML180UH135E60DKSL280UH060NV36ASL280UH070V36ASL280UH080NV48BSL280UH080NV60CSL280UH090V36BSL280UH090V48BSL280UH090V60CSL280UH100NV60CSL280UH110V60CSL280UH135V60DSL297UH040NV36BSL297UH060NV36BSL297UH080NV48CSL297UH080NV60C

Other Lennox Furnace codes

CodeMeaning
70003IAQ side switch in OFF position
70004Replace Smart IAQ monitor
70501Smart room sensor internal data fault
70502Smart room sensor internal fault
70503Smart room sensor low battery
70504Smart room sensor battery 1%
71511Duct or filter blockage
71517Indoor fan motor failure
80001IAQ persistent poor air quality
80002Unresponsive wireless device fault
80003Lost communication with wireless device
80005Unknown wireless device found

All Lennox Furnace error codes →

Lennox code 71001: homeowner questions

What does Lennox code 71001 mean?

Wireless extender internal data fault. Wireless extender cannot access internal data. S30/S40 thermostat alert code 71001.

Is it safe to keep using my furnace with code 71001?

It depends on the cause. This is often caused by something simple. Try the safe checks below; if the code returns, book a service call before it turns into a no-heat or no-hot-water emergency.

Can I reset Lennox code 71001 myself?

You can try one reset (power off for 30 seconds, then on). If Lennox code 71001 comes back, the cause is still there and a licensed technician should check it.

Who can fix Lennox code 71001 near me?

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

Homeowner help: Furnace Not Turning On: What to Check · Furnace Blinking Light: What the Flash Codes Mean

Troubleshooting guides

Source: Lennox Residential Communicating Systems Alert Code Guide (V2) 100017 (3/2023), Table 2 Alert Codes and Troubleshooting, p.49. 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.

Emergency Furnace Repair

647-657-2977