On the covered Google Nest thermostat, W3, W4 means the thermostat failed to connect. For W3, Google says the router is not giving the thermostat a network IP address. For W4, the thermostat is connected to the wireless network but not to the internet. First, check whether other devices on the same Wi-Fi network can reach the internet.
Differential
Likely causes of “Google Nest thermostat code W3, W4”, and how to tell them apart
- 1
The router gives no IP address
What separates it The thermostat joins but gets no address
How to confirm Restart the router and check DHCP
- 2
The network has no internet
What separates it The thermostat is on Wi-Fi without internet
How to confirm Check that other devices reach the internet
- 3
A router filter or address pool full
What separates it The router refuses new devices
How to confirm Check connected devices and filters
- 4
A modem or provider outage
What separates it Every device is offline
How to confirm Restart the modem or call the provider
- 5
A weak or interrupted signal
What separates it The link drops
How to confirm Improve the signal at the thermostat
Before you touch a setting
Record this first — changing settings destroys the evidence
- Whether the code is W3 or W4
- Whether other devices have internet
- The router's lights
- Whether it began after a change
Try in this order
0 of 8 completedWhat to do first
ReversibleCheck whether other devices on the same Wi-Fi network can reach the internet.
Correct only the documented fault domain
ReversibleGoogle points both codes to its "Troubleshooting a Failed to connect code" article. Google's table puts the cause on the network side in both cases: for W3 the router is not handing the thermostat an IP address, and for W4 the thermostat is on the wireless network but the network has no internet.
Check which code shows
ReversibleW3 or W4.
Test other devices
ReversibleDo they reach the internet?
Restart the modem and router
ReversibleIn order.
Look at the router's device list
ReversibleFor free addresses.
Reconnect the thermostat
ReversibleUnder Settings, Network.
Read Google's article
ReversibleTroubleshooting a failed to connect code.
Model-specific
What is true of this model and not of its siblings
- Two codes, two stages
- W3 means the thermostat reached the Wi-Fi network but the router did not hand it an address. W4 means it has an address but no route to the internet. Knowing which tells you whether to look at the router's address settings or at the modem and provider.
- What to check at home
- If phones and laptops on the same Wi-Fi have internet, the router and modem are working, and the cause is likely the router's handling of the thermostat. If they have none, fix the internet first.
- When it follows a change
- A new router, a changed password or a new modem often triggers W3 or W4, so reconnect the thermostat from Settings, Network.
Stop boundary
When this stops being a self-service repair
- !Google's table puts the cause on the network side
- !Contact your provider if the whole network is offline
- !Contact Google Nest support if the network is fine
Evidence ledger
Sources behind this answer
Exact questions
Common questions
What does W3, W4 mean on a Google Nest thermostat?+
The thermostat failed to connect. For W3, Google says the router is not giving the thermostat a network IP address. For W4, the thermostat is connected to the wireless network but not to the internet.
Is the thermostat broken?+
Google puts the cause on the network.
What do I try first?+
Check other devices on the same network.
Where is the Google article?+
Troubleshooting a failed to connect code.