A Honeywell smart thermostat is an excellent way to better manage how you use your home comfort system. But like any technology, you might occasionally experience a problem. With its digital display, Honeywell smart thermostats can provide an error code that certified technicians will use to figure out what’s happening. Here are several of the most common error codes you may see on your Honeywell smart thermostat.

Honeywell Thermostat Error e42

You can receive this error code if your home’s Wi-Fi connection did not supply an IP address for the thermostat to connect with. This can occur if the router fails to perform the Dynamic Host Configuration Protocol, or DHCP. This process automatically sends out the required IP address for your thermostat to link up.

How to Fix Honeywell Thermostat Error e42

You can fix error code e42 by making sure that your router can complete the DHCP. Assuming it does, you may also need to power cycle the router and perform the setup process again with your thermostat. Completing this task should see to it that the DHCP is transmitted and connects to the smart thermostat.

Error Code e02 for Honeywell Thermostats

Error code e02 is displayed if the password for communicating with your home’s Wi-Fi router was incorrect. Once this error code is displayed for 30 seconds, the thermostat’s digital display will automatically progress to the Wi-Fi setup screen so you can attempt to enter the password again.

How to Fix Honeywell Thermostat Error e02

All you need to do to resolve error e02 is make sure you’re typing the correct Wi-Fi password when setting up the thermostat.

Error Code 40 for Honeywell Thermostats

Error code 40 can pop up when the thermostat is notified that a heat pump or air conditioner’s monitoring system has identified a malfunction. For the most part, this occurs once the compressor isn’t turning on despite being instructed to. But this error code could also show up if power is disconnected from the outdoor unit for a long period of time. A “High Pressure Fault” error, induced by poor airflow, can lead to this error code. Finally, you might experience error code 40 if there’s a problem with the coolant, the outdoor unit’s fan motor or the motor’s starting capacitor.

How to Fix Honeywell Thermostat Error 40

You can examine the air filter for signs of a clog, as well as the breakers and indoor unit’s blower for ordinary operation. If you reset the thermostat and error code 40 reappears, you should try to contact an experienced technician.

Honeywell Thermostat Error e43

If your Honeywell thermostat presents error code e43, it is failing to communicate with the router, and by extension the Wi-Fi. This might happen if the router’s ethernet cable isn’t plugged in or it isn’t communicating with the wide area network (WAN).

How to Fix Honeywell Thermostat Error e43

Reboot the router by unplugging it and leaving it that way for about 30 seconds. The thermostat may also be disconnected if you have recently changed the password or the Wi-Fi’s SSID, which is the name you provide it.

Honeywell Thermostat Error e1

Thermostats utilize sensors to identify the temperature outdoors and indoors. If a sensor breaks down, you may see error code e1 appear on your Honeywell smart thermostat.

How to Fix Honeywell Thermostat Error e1

A qualified technician can change out the sensor and reset the thermostat, which should clear error code e1.

Honeywell Error Code 11n

Error code 11n can appear in situations where the thermostat is unable to connect to a heating or cooling unit. This can mean that the equipment itself is faulty and unable to maintain a connection to the thermostat. This sometimes happens when the wiring is damaged or even if the thermostat has failed.

How to Fix Honeywell Thermostat Error 11n

A qualified technician can use a voltmeter to assess if there’s a poor electrical connection. In situations where the wiring on your existing HVAC system is bad, the technician can replace it. In situations where the thermostat itself is the issue, it should probably be replaced.

Honeywell Thermostat Error e2

If you notice error code e2 pop up on your Honeywell smart thermostat, it could mean a few different things. Sometimes, one of the sensors that detects the temperature isn’t working properly. In other cases, it means the router was disconnected from power before the thermostat finished the setup process.

How to Fix Honeywell Thermostat Error e2

When the error code is a result of sensor failure, a technician should troubleshoot and replace the damaged sensor. If the problem comes from disconnected power, all you’ll need to do is make sure the router stays on throughout the setup process.