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Lennox Error Code E126: Control internal communication problem (Furnace)

Updated · by Aurora Star Tech Inc.

Lennox error code E126 on a furnace means: Control internal communication problem. It is also called Lennox diagnostic code E126.

High severityFurnaceEL296UHV · Lennox SL280UHV · Lennox SL297NV

Homeowner? What Lennox code E126 means for you

Call a technician Your furnace is reporting: Control internal communication problem. The furnace 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.
  • 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 E126 mean?

Hardware problem inside the integrated control.

Applies to: EL296UHV(X) series furnaces with integrated control 103130-XX only

Common causes of Lennox code E126

  • Integrated control hardware 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 E126

Show all 22 models

EL296UH045XV36BEL296UH070XV36BEL296UH090XV36CEL296UH090XV48CEL296UH090XV60CEL296UH110XV48CEL296UH110XV60CEL296UH135XV60DSL280UH060NV36ASL280UH070V36ASL280UH080NV48BSL280UH080NV60CSL280UH090V36BSL280UH090V48BSL280UH090V60CSL280UH100NV60CSL280UH110V60CSL280UH135V60DSL297UH040NV36BSL297UH060NV36BSL297UH080NV48CSL297UH080NV60C

Other Lennox Furnace codes

CodeMeaning
E115Low 24 VAC
E116High 24 VAC
E117Poor ground detected
E120Unresponsive device
E124Lost communication with thermostat
E125Control hardware failure
E130Configuration jumper missing
E131Corrupted control parameters
E132Device control software fault
E150A2L refrigerant leak alarm
E151A2L sensor fault
E152Refrigerant leak sensor #2 fault

All Lennox Furnace error codes →

Lennox code E126: homeowner questions

What does Lennox code E126 mean?

Control internal communication problem. Hardware problem inside the integrated control.

Is it safe to keep using my furnace with code E126?

It depends on the cause. The furnace 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 E126 myself?

You can try one reset (power off for 30 seconds, then on). If Lennox code E126 comes back, the cause is still there and a licensed technician should check it.

Who can fix Lennox code E126 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 EL296UHV(X) Unit Information / Service Literature, Table 5 Ignition Control 103130-XX Diagnostic Codes, p.34. 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