Error Code E42: How to Fix This Honeywell Thermostat Code

A Honeywell smart thermostat is a great way to optimize how you use your heating and cooling. But like any utility, you could sometimes run into a problem. With a digital display, Honeywell smart thermostats can provide an error code that professional technicians use to get a better sense of what's happening. Here are a few of the most known error codes you could see on your Honeywell smart thermostat.

Error Code e42 for Honeywell Thermostats

You may receive this error code when your home’s Wi-Fi connection did not present an IP address for the thermostat to connect with. This can take place if your router does not complete the Dynamic Host Configuration Protocol, or DHCP. This procedure automatically transmits the necessary IP address for your thermostat to connect.

How to Fix Honeywell Thermostat Error e42

You can fix error code e42 by confirming that your router can complete the DHCP. Assuming it does, you may also have to power cycle the router and repeat the initial setup process with the thermostat. This should see to it that the DHCP is transmitted and connects to your smart thermostat.

Honeywell Thermostat Error e02

Error code e02 is displayed whenever the password for connecting to your home’s Wi-Fi router is not correct. Once this error code has appeared for 30 seconds, the thermostat’s digital display will automatically progress to the Wi-Fi setup screen so you can try to enter the password again.

How to Fix Honeywell Thermostat Error e02

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

Honeywell Error Code 40

Error code 40 can show up when the thermostat is notified that a heat pump or air conditioner’s monitoring system has recognized 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 shut off from the outdoor unit for a long period of time. A “High Pressure Fault” error, caused by poor airflow, can display this error code. And finally, you may encounter 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 examine 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, it's time to contact an experienced technician.

Honeywell Error Code e43

If the Honeywell thermostat presents error code e43, it can’t communicate with the router, and by extension your Wi-Fi. This may 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 might 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 employ sensors to detect the temperature outdoors and indoors. If a sensor fails, you may see error code e1 show up on your Honeywell smart thermostat.

How to Fix Honeywell Thermostat Error e1

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

Honeywell Thermostat Error 11n

Error code 11n can appear in situations where the thermostat is failing to recognize a heating or cooling unit. This may mean that the equipment itself is defective and unable to connect with the thermostat. This sometimes happens when the wiring is bad 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 bad electrical connection. In situations where the wiring on your type of HVAC system is bad, the technician can replace it. When the thermostat itself is the problem, it should probably be replaced.

Honeywell Thermostat Error e2

If you see error code e2 show up on your Honeywell smart thermostat, it might mean a couple of different things. In some cases, one of the sensors used to detect the temperature isn’t functioning properly. In other instances, it means the router was disconnected from power before the thermostat could complete the setup process.

How to Fix Honeywell Thermostat Error e2

In situations where the error code stems from sensor failure, a technician can troubleshoot and replace the affected sensor. If the problem originates from disconnected power, all you’ll have to do is make sure the router remains on during the setup process.