Error Code E42: How to Fix This Honeywell Thermostat Code

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 sometimes experience a problem. With the digital display, Honeywell smart thermostats can show an error code that trained technicians can use to understand what's happening. Here are some of the most likely error codes you may see on your Honeywell smart thermostat.

Error Code e42 for Honeywell Thermostats

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

How to Fix Honeywell Thermostat Error e42

You can fix error code e42 by confirming that your router is enabled for DHCP. When it does, you might also need to power cycle the router and complete the initial setup process again with the thermostat. Completing this task should ensure the DHCP is delivered and connects to the smart thermostat.

Honeywell Thermostat Error e02

Error code e02 is displayed when the password for accessing your home’s Wi-Fi router is incorrect. After this error code has appeared for 30 seconds, the thermostat’s digital display automatically transitions to the Wi-Fi setup screen so you can try 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 configuring the thermostat.

Error Code 40 for Honeywell Thermostats

Error code 40 can pop up when the thermostat is informed that a heat pump or air conditioner’s monitoring system has detected a malfunction. Most often, this occurs once the compressor isn’t working 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, caused by obstructed airflow, can lead to this error code. Finally, you could encounter error code 40 if there’s something wrong with the coolant, 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 regular operation. If you restart the thermostat and error code 40 reappears, it's time to get in touch with an experienced technician.

Honeywell Thermostat Error e43

If a Honeywell thermostat presents error code e43, it can’t communicate with the router, and by extension your Wi-Fi. This could 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

Reset the router by unplugging it and leaving it that way for about 30 seconds. The thermostat could also be disconnected if you recently switched the password or the Wi-Fi’s SSID, which is the name you create for it.

Honeywell Error Code e1

Thermostats employ sensors to determine the temperature outdoors and indoors. If a sensor malfunctions, you might notice error code e1 turn up on your Honeywell smart thermostat.

How to Fix Honeywell Thermostat Error e1

A trained technician can change out the sensor and reset the thermostat, which should take care of 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 might mean that the equipment itself is malfunctioning and unable to connect with the thermostat. This sometimes happens when the wiring is defective or even if the thermostat is faulty.

How to Fix Honeywell Thermostat Error 11n

A licensed technician can utilize a voltmeter to assess if there’s a poor electrical connection. If the wiring on your specific HVAC system is bad, the technician can replace it. When the thermostat itself is the issue, it should probably be replaced.

Error Code e2 for Honeywell Thermostats

If you notice error code e2 show up on your Honeywell smart thermostat, it can mean a couple of different things. Sometimes, one of the sensors responsible for detecting the temperature isn’t operating properly. In other instances, it means the router was disconnected from its power source before the thermostat finished the setup process.

How to Fix Honeywell Thermostat Error e2

When the error code stems from sensor failure, a technician should troubleshoot and switch out the damaged sensor. Any time the problem originates from disconnected power, all you’ll have to do is see to it that the router remains on throughout the setup process.