Solved: Honeywell Thermostat Error Codes

November 08, 2022

A Honeywell smart thermostat is an excellent way to better manage how you use your home comfort system. But like any mechanical system, you may occasionally run into a problem. With its digital display, Honeywell smart thermostats can display an error code that trained technicians will use to understand what's wrong. Here are a few of the most likely error codes you may see on your Honeywell smart thermostat.

Honeywell Thermostat Error e42

You might encounter this error code if your home’s Wi-Fi connection did not present an IP address for the thermostat to hook up to. This can occur if your router does not execute the Dynamic Host Configuration Protocol, or DHCP. This process automatically sends out the needed IP address for your thermostat to connect.

How to Fix Honeywell Thermostat Error e42

You can fix error code e42 by making sure that your router is enabled for DHCP. If it does, you may also need to power cycle the router and repeat the initial setup process with the thermostat. This should see to it that the DHCP is delivered and connects to the smart thermostat.

Honeywell Thermostat Error e02

Error code e02 appears if the password for connecting to your home’s Wi-Fi router was incorrect. When this error code is displayed for 30 seconds, the thermostat’s digital display should automatically transition to the Wi-Fi setup screen so you can attempt to enter the password again.

How to Fix Honeywell Thermostat Error e02

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

Honeywell Thermostat Error 40

Error code 40 can appear when the thermostat is notified that a heat pump or air conditioner’s monitoring system has detected a malfunction. Most often, this occurs once the compressor isn’t running despite being instructed to. But this error code can also appear if power is disconnected from the outdoor unit for a lengthy period of time. A “High Pressure Fault” error, caused by blocked airflow, can display this error code. And finally, you could experience error code 40 if there’s an issue with the refrigerant, the outdoor unit’s fan motor or the motor’s starting capacitor.

How to Fix Honeywell Thermostat Error 40

You can inspect the air filter for signs of a clog, as well as the breakers and indoor unit’s blower for normal operation. If you turn the thermostat off and on again and error code 40 reappears, you should try to get in touch with an experienced technician.

Honeywell Thermostat Error e43

If the Honeywell thermostat presents error code e43, it is unable to communicate with the router, and by extension your Wi-Fi. This can 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 a short period. The thermostat may also be disconnected if you’ve recently updated the password or the Wi-Fi’s SSID, which is the name you create for it.

Honeywell Thermostat Error e1

Thermostats utilize sensors to detect the temperature outdoors and indoors. If a sensor fails, you could see error code e1 turn up on your Honeywell smart thermostat.

How to Fix Honeywell Thermostat Error e1

A trained technician can replace the sensor and restart the thermostat, which should resolve error code e1.

Honeywell Thermostat Error 11n

Error code 11n may appear if the thermostat is failing to detect a heating or cooling unit. This may mean that the equipment itself is malfunctioning and unable to communicate with the thermostat. This can happen when the wiring is defective or even if the thermostat has failed.

How to Fix Honeywell Thermostat Error 11n

A licensed technician can utilize a voltmeter to assess if there’s a faulty electrical connection. In situations where the wiring on your type of HVAC equipment is bad, the technician can replace it. If the thermostat itself is the issue, it will likely have to be replaced.

Honeywell Thermostat Error e2

If you see error code e2 show up on your Honeywell smart thermostat, it can mean several different things. Sometimes, one of the sensors that detects the temperature isn’t functioning like it should. Other times, it means the router was disconnected from the outlet before the thermostat completed the setup process.

How to Fix Honeywell Thermostat Error e2

In situations where the error code is caused by sensor failure, a technician should troubleshoot and replace the impacted sensor. Any time the problem comes from disconnected power, all you have to do is make sure the router stays on throughout the setup process.