What causes Lennox Gas Furnace E201?

A power outage, brownout, or tripped breaker that interrupted the furnace or motor (Lennox lists power outage and brownout first). The blower motor isn't receiving 120V line power: a loose 5-pin power plug at the motor or a wiring fault. A loose, unseated, or damaged 4-pin low-voltage (communication) plug between the control and the motor. Condensation or moisture on the air-handler control, for example when the breaker cover is missing (per Lennox's iComfort guide). A failed ECM blower motor or its motor controller. A failed furnace integrated control board (Lennox notes the problem may be on the control or the motor side).

How do I fix Lennox Gas Furnace E201?

Read the code: watch the furnace's seven-segment LED through the sight glass, or check the alert on your Lennox thermostat. You can recall the last 10 error codes by holding the diagnostic button until 'E' shows, then releasing it. Check for a simple power problem first: was there a recent outage or storm? Make sure the furnace breaker hasn't tripped and the furnace service switch is on. Cycle power: turn off the furnace switch or breaker, wait at least 5 minutes, then turn it back on. If the outage was the cause, E201 clears once the control and motor reconnect. If it comes back, turn power off again and wait at least 5 minutes before touching anything near the motor. Lennox warns the motor's internal capacitors hold a dangerous charge for about 5 minutes after power is removed. Remove the blower door and look at the two plugs on the blower motor: the 5-pin power plug and the 4-pin low-voltage plug. Push each firmly into place and look for burnt, corroded, or pulled wires. On an air handler, check for moisture on the control board and make sure the breaker cover is installed. Reinstall the door (the furnace won't run with the door interlock switch open), restore power, and watch for the code. If E201 returns, call a technician.

When should I call a pro for Lennox Gas Furnace E201?

E201 keeps coming back after a full power cycle and reseating the motor plugs. The blower doesn't run at all. Lennox's motor check involves measuring 120V on live pins and jumpering 24V to specific pins on the motor's low-voltage connector, and applying 24V to the wrong pins permanently damages the motor, so leave this to a pro. You see burnt or melted connectors, water damage on the control board, or signs of a power surge. The ECM motor or integrated control needs replacing. Lennox notes earlier ECM motors aren't interchangeable with those in its newer furnaces, and a replacement control may need the furnace unit size code programmed. You smell gas: leave the house and call your gas utility from outside.

Code: E201🔥 Lennox Gas Furnace

Lennox Furnace Error 201 (E201): Lost Communication With the Blower Motor (Meaning, Causes, Fixes)

Q: What does Lennox Gas Furnace E201 mean?

Error 201 on a Lennox furnace or air handler means the control board lost communication with the variable-speed indoor blower motor. Lennox lists the usual causes as a power outage or brownout, a motor that isn't getting power, or loose wiring, and the problem can be on either the control side or the motor side. It clears on its own once communication is restored. Lennox service literature for its communicating SureLight furnaces (SL280V-series and similar) defines E 201 as 'Indoor blower communication failure - Unable to communicate with blower motor', including after a power outage. On these furnaces the blower is an ECM motor that takes all of its instructions (direction, demand, motor size, airflow) from the furnace's integrated control over a two-way serial connection, so if that conversation drops, the furnace can't run the blower and shuts down heating or cooling. The code shows on the furnace's seven-segment LED one character at a time (E, 2, 0, 1), and on an iComfort or other Lennox communicating thermostat it appears as a critical alert 201. Lennox's iComfort guide adds condensation on the air-handler control and a missing breaker cover as possible causes, and says the alert clears after communication is restored.

Reviewed 2026-10-21 · Based on 4 manufacturer & service sources

What the code means

Lennox service literature for its communicating SureLight furnaces (SL280V-series and similar) defines E 201 as 'Indoor blower communication failure - Unable to communicate with blower motor', including after a power outage. On these furnaces the blower is an ECM motor that takes all of its instructions (direction, demand, motor size, airflow) from the furnace's integrated control over a two-way serial connection, so if that conversation drops, the furnace can't run the blower and shuts down heating or cooling. The code shows on the furnace's seven-segment LED one character at a time (E, 2, 0, 1), and on an iComfort or other Lennox communicating thermostat it appears as a critical alert 201. Lennox's iComfort guide adds condensation on the air-handler control and a missing breaker cover as possible causes, and says the alert clears after communication is restored.

Likely causes

A power outage, brownout, or tripped breaker that interrupted the furnace or motor (Lennox lists power outage and brownout first)
The blower motor isn't receiving 120V line power: a loose 5-pin power plug at the motor or a wiring fault
A loose, unseated, or damaged 4-pin low-voltage (communication) plug between the control and the motor
Condensation or moisture on the air-handler control, for example when the breaker cover is missing (per Lennox's iComfort guide)
A failed ECM blower motor or its motor controller
A failed furnace integrated control board (Lennox notes the problem may be on the control or the motor side)

Safe DIY checks

⚠ Before you start

Turn off power at the furnace/HVAC service switch and the breaker before opening panels. Shut the gas valve before any work near the burners, and never disconnect or alter the gas line. If you smell gas, leave the house and call your gas utility.

Read the code: watch the furnace's seven-segment LED through the sight glass, or check the alert on your Lennox thermostat. You can recall the last 10 error codes by holding the diagnostic button until 'E' shows, then releasing it.
Check for a simple power problem first: was there a recent outage or storm? Make sure the furnace breaker hasn't tripped and the furnace service switch is on.
Cycle power: turn off the furnace switch or breaker, wait at least 5 minutes, then turn it back on. If the outage was the cause, E201 clears once the control and motor reconnect.
If it comes back, turn power off again and wait at least 5 minutes before touching anything near the motor. Lennox warns the motor's internal capacitors hold a dangerous charge for about 5 minutes after power is removed.
Remove the blower door and look at the two plugs on the blower motor: the 5-pin power plug and the 4-pin low-voltage plug. Push each firmly into place and look for burnt, corroded, or pulled wires.
On an air handler, check for moisture on the control board and make sure the breaker cover is installed.
Reinstall the door (the furnace won't run with the door interlock switch open), restore power, and watch for the code. If E201 returns, call a technician.

🛠 When to call a pro

E201 keeps coming back after a full power cycle and reseating the motor plugs.
The blower doesn't run at all. Lennox's motor check involves measuring 120V on live pins and jumpering 24V to specific pins on the motor's low-voltage connector, and applying 24V to the wrong pins permanently damages the motor, so leave this to a pro.
You see burnt or melted connectors, water damage on the control board, or signs of a power surge.
The ECM motor or integrated control needs replacing. Lennox notes earlier ECM motors aren't interchangeable with those in its newer furnaces, and a replacement control may need the furnace unit size code programmed.
You smell gas: leave the house and call your gas utility from outside.

Parts that commonly fix it

Always match the part number to your exact model.

⚙

Lennox ECM indoor blower motor (exact OEM part for your furnace model)

Only after a technician confirms the motor has failed. Lennox says older ECM motors aren't interchangeable, so match your model number.

[affiliate link slot: AFFILIATE_SLOT_BLOWER_MOTOR]

⚙

Lennox SureLight integrated control board (exact OEM part number)

Last resort if the motor tests good. A replacement control may need the unit size code set.

[affiliate link slot: AFFILIATE_SLOT_BOARD]

⚙

Digital multimeter

For confirming the furnace is getting power.

[affiliate link slot: AFFILIATE_SLOT_MULTIMETER]

⚙

Whole-house surge protector

Optional, if outages or surges keep triggering blower and board faults.

[affiliate link slot: AFFILIATE_SLOT_SURGE]

Sources

Last reviewed 2026-10-21. Always confirm against the manual for your exact model number.