Stumbling upon the Honeywell WiFi thermostat E43 error? Keep reading to uncover the fix!
The “E43” error is primarily caused by connectivity issues between the thermostat and router.
So, no matter how common the “E43” error on the Honeywell thermostat is, there is always a thing or two to attempt to get rid of the error code so let’s uncover more…
The “E43” error code on the Honeywell thermostat can be fixed by double-checking the Wi-Fi password you’ve inserted into the thermostat.
If you’re still encountering the error code, reboot the network device (router or modem) and factory reset the thermostat!
Understanding the Honeywell WiFi Thermostat Error E43!
Honeywell thermostat error E43 is a general type of error that occurs whenever there’s a connection timeout between the thermostat and the network device.
The problem can be either on the thermostat end or on the WiFi router’s end, so we examine the issue further!
Here are the top causes for the E43 thermostat error on your Honeywell thermostat:
These are the possibilities so we’ve designed an easy guide to address them all at once!
7 Ways to Fix Honeywell WiFi Thermostat E43 Error Code?
1. Correct the Wi-Fi Password!
The primary cause of the “E43” error on your Honeywell thermostat is an incorrect Wi-Fi password.
It is possible that you’ve mistyped or misspelled a letter from the router’s password, thus, the thermostat could not establish a connection with the network device at all.
How to Correct the Honeywell Thermostat Wi-Fi Password?
- Open the Honeywell app on your mobile devices.
- Navigate to “Devices” and tap on your thermostat.
- Go to “Wi-Fi Setup” and follow the first instructions.
- At the “Password” page, insert the correct password.
How to Test Wi-Fi Password?
If you’ve recently got a new router or changed the password of your current one, chances are that you have repeatedly input the password incorrectly.
So, simply unpair your mobile device from Wi-Fi and attempt using the same password you’ve typed in the thermostat.
Info: If your mobile device could not reconnect to the Wi-Fi, check the password settings of the router/network device in the web GUI!
2. Reinsert the Thermostat Batteries
To erase any temporal issues with the Honeywell thermostat, taking the batteries out and then placing them back in will do the trick.
The “E43” message is considered to be a temporary fault and by performing the so-called “hard reset”, any non-lasting issues will be solved with ease!
Here’s how to reinstall the batteries of the Honeywell thermostat:
- Locate the battery compartment on the side of the thermostat.
- Press the release button at the top of the compartment’s latch.
- Once loosened, pull out the compartment and eject the batteries.
- Wait for 30 seconds while the batteries are out from the thermostat.
- Place the batteries back into the compartment and close the latch.
Are Thermostat Batteries Bad?
If you have been observing unusual behavior of the Honeywell thermostat, such as turning off, rebooting, freezing, or other error codes, it’s the batteries.
Honeywell thermostats either take two AA or AAA alkaline batteries, so replace them by opening the compartment again.
Tip: Change the batteries of the thermostat often to maintain optimal performance!
3. Power Cycle the Network Router!
Another cause for the “E43” error given by your Honeywell thermostat is constant connectivity timeouts.
A problem with the network router could be responsible for the thermostat’s error and to approach the problem effectively, conduct a router the so-called “power circulation”.
Note: This method will not erase any of the thermostat settings!
Here’s how to power cycle any network router in easy steps:
- Press the power button on the router to turn the device off.
- Then, unplug the power adapter of the router from the wall.
- Wait for 40 seconds while the power cable is disconnected.
- Re-attach the adapter of the network router back into power.
- Wait for your network router to turn on and become online!
Tip: We recommend keeping the router unplugged for longer to prevent overheating!
4. Connect to a 2.4GHz Wi-Fi Network
In case there has been a misunderstanding in the compatibility parameters of your Honeywell, now is the time to clarify that only 2.4 GHz WiFi frequency is compatible.
Thus, selecting the 5 GHz frequency WiFi network in the “Wi-Fi Setup” menu will result in the “E43” error code!
I Only Have a 5 GHz Frequency WiFi.
If your router is capable of transmitting 5 GHz WiFi, then surely, 2.4 GHz WiFi is available but might be disabled.
The so-called “dual-band” routers can operate on both frequencies or on only one of them at a time, so if you only have 5 GHz WiFi, then you need to set up 2.4 GHz WiFi.
How to Host a 2.4GHz Wi-Fi Network?
- Connect a laptop or a PC to the router via an Ethernet cable.
- Open a web browser and navigate to “http://192.168.100.1/”.
- Sign in using admin/admin or admin/password credentials.
- Go to the “Networks” tab and click on “Add New Network”.
- At “Preferences”, choose “2.4GHz” and follow the steps.
Note: If the instructions do not apply to your router, contact your service provider for help!
5. Reset the Thermostat Wi-Fi Settings
A misconfiguration of the Wi-Fi settings of the Honeywell thermostat could result in the “E43” connectivity timeout error.
To properly address the problem, you must reset the Wi-Fi settings of the Honeywell thermostat by triggering connectivity settings reset from the options.
Here’s how to reset the Wi-Fi settings of the Honeywell thermostat:
- On the thermostat, press the “Fan” button + the Up Arrow for 5 seconds.
- Wait until the screen of the thermostat changes and release the buttons.
- Press the “Back” or “Next” button until a “39” appears on the display.
- Press the “Up” or “Down” arrows to set the number from “39” to “0”.
- Tap the “Done” button at the bottom of the display once a “0” appears.
- The “Wi-Fi Setup” option will appear on the thermostat after 1-2 minutes.
Info: Once the “Wi-Fi Setup” option re-appears, all connectivity details will have been erased!
6. Reconnect the Router Service
It is possible that the Honeywell thermostat is not able to communicate with the router due to a fault in the service cable connection.
If your network consists of a separate router and modem, the fault is with the Ethernet cable, but if you have a gateway, it’s with the Coaxial cable.
How to Refresh the Service of a Network Device?
- On the gateway, unplug the coaxial cable from the wall outlet and from the port.
- On modem/router combo, unplug the Ethernet cable from the network router.
Tip: Inspect the Service Cable!
While the service cable is out thoroughly examine the service cable (Ethernet or Coax) and try to spot any visual hardware damages.
It’s necessary to verify that the internet service cable is working and your WiFi is not fluctuating, since any outages ultimately lead to error “E43”.
Tip: Use a free internet speed test tool to measure the consistency of your WiFi.
7. Factory Reset the Honeywell Thermostat!
To put an end to the persistent “E43” Honeywell thermostat error, it is recommended to conduct a factory reset on the Honeywell thermostat.
This reset will help with any underlying software issues with the device and resolve pending error codes such as the “E43” you’re encountering!
To reset the Honeywell thermostat, install the batteries in the wrong way!
Hence, the negative pole of the battery must be facing the positive pole for both batteries in the compartment of the thermostat.
Wait for 10 seconds and then place the batteries back into the correct positions, which will ultimately factory reset the thermostat.
Note: Any thermostat settings, schedules, and configuration will be permanently lost!
Hence, to fix the Honeywell WiFi thermostat E43 error, replace the thermostat’s batteries first, and then reset the Wi-Fi settings.
If the problem is still there, perform a power cycle on the network router and verify that the thermostat is connecting to a 2.4GHz WiFi.
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Kevin has over five years of experience working in various Tech startups and providing Technical solutions. He has contributed to many Tech publications and websites.