Error Code E42: How to Fix This Honeywell Thermostat Code

A Honeywell smart thermostat is an easy way to better manage how you use your home comfort system. But like any technology, you could sometimes run across a problem. With a digital display, Honeywell smart thermostats can provide an error code that certified technicians can use to get a better sense of what's wrong. Here are a few of the most common error codes you could see on your Honeywell smart thermostat.

Honeywell Thermostat Error e42

You can receive this error code if your home’s Wi-Fi internet did not supply an IP address for the thermostat to connect to. This can occur if the router fails to complete the Dynamic Host Configuration Protocol, or DHCP. This procedure automatically supplies the required IP address for your thermostat to connect.

How to Fix Honeywell Thermostat Error e42

You can clear error code e42 by confirming that your router can complete the DHCP. When it does, you might also have to power cycle the router and repeat the initial setup process with the thermostat. Doing so should see to it that the DHCP is sent and connects to the smart thermostat.

Honeywell Error Code e02

Error code e02 is displayed if the password for connecting to your home’s Wi-Fi router is 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 try the password again.

How to Fix Honeywell Thermostat Error e02

All you have to do to solve error e02 is verify you’re typing the correct Wi-Fi password when configuring the thermostat.

Honeywell Thermostat Error 40

Error code 40 can appear when the thermostat is alerted that a heat pump or air conditioner’s monitoring system has identified a malfunction. Most commonly, this occurs once the compressor isn’t working despite being instructed to. But this error code could also appear if power is disconnected from the outdoor unit for a long period of time. A “High Pressure Fault” error, triggered by obstructed airflow, can lead to this error code. And finally, you may see error code 40 if there’s a problem with the refrigerant, the outdoor unit’s fan motor or the motor’s starting capacitor.

How to Fix Honeywell Thermostat Error 40

You can check 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 get in touch with an experienced technician.

Honeywell Error Code e43

If the Honeywell thermostat displays 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 your wide area network (WAN).

How to Fix Honeywell Thermostat Error e43

Reset the router by unplugging it and leaving it that way for a short period. The thermostat might also be disconnected if you recently updated the password or the Wi-Fi’s SSID, which is the name you provide it.

Honeywell Thermostat Error e1

Thermostats use sensors to identify the temperature outdoors and indoors. If a sensor breaks down, you may notice error code e1 turn up on your Honeywell smart thermostat.

How to Fix Honeywell Thermostat Error e1

A qualified technician can change out the sensor and reboot the thermostat, which should take care of error code e1.

Honeywell Thermostat Error 11n

Error code 11n can appear if the thermostat can’t detect a heating or cooling unit. This can mean that the equipment itself is defective and unable to communicate with the thermostat. This can happen when the wiring is damaged or even if the thermostat is faulty.

How to Fix Honeywell Thermostat Error 11n

A qualified technician can utilize a voltmeter to find out if there’s a poor electrical connection. When the wiring on your specific HVAC equipment is bad, the technician can replace it. When the thermostat itself is the problem, it will likely have to be replaced.

Error Code e2 for Honeywell Thermostats

If you’ve noticed error code e2 pop up on your Honeywell smart thermostat, it could mean a few different things. In some cases, one of the sensors that detects the temperature isn’t functioning correctly. 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

When the error code is caused by sensor failure, a technician can troubleshoot and switch out the damaged sensor. Any time the problem comes from disconnected power, all you have to do is see to it that the router remains on over the course of the setup process.