- HVAC
- Smart thermostats
E10
Google Nest E10 on smart thermostat: no Y1 power in cold weather
Risk level
Medium
Proceed carefully and stop if the check is unclear.
Urgency
High
Quick answer
E10 on a Nest (or E30, E66, E80, E116, E160, E196, E296) means it was powering itself from the AC's Y1 wire and that power stopped, often in extreme cold. Google gives a quick fix to get heat back and asks a professional to install a C wire.
Safety first
Stop and check this first
- After the quick fix the air conditioner won't work until the Y1 wire is reconnected; don't forget it before summer.
- A disconnected wire left untaped can touch another and cause a short circuit that damages the thermostat or the equipment.
Safe checks you can perform
- Whether E10 coincides with extreme cold
- Thermostat battery with E10 or E296
- Google's quick fix to get heat back
Leave these tasks to a qualified professional
- Do not attempt this professional task: Install a C wire or Nest Power Connector and reconnect Y1
- Do not attempt this professional task: Diagnose why the AC stopped powering Y1
What a technician must be able to justify
Technician visit
These are the steps they must carry out and show you. Tick them as they work: if steps are skipped, do not accept a part swap.
These are not instructions for opening or handling the equipment yourself. They are the checks that should support a technical conclusion.
Install a C wire or Nest Power Connector and reconnect Y1
What they doThe installer connects a common wire (or an existing free wire) or the Nest Power Connector, reconnects Y1 and tests heating and cooling.
They must show youthe C wire landed on the board and the base, Y1 reconnected and the cooling and heating test.
In writingwhich solution was installed and that Y1 is connected again.
Diagnose why the AC stopped powering Y1
What they doThe HVAC technician inspects the air conditioner, including the low pressure or safety cutout switch, and uses a multimeter to check whether voltage reaches the Y1 wire when it should.
They must show youwhich device cut the power and the Y1 reading with the system running.
In writingthe cause found (cold protection, fault or maintenance) and what was done.
Before accepting a part or repair
Nothing has been shown yet. Do not accept a part swap based on the code alone.
Follow these steps
Note: Follow the documented order. An error code identifies the affected system, but it does not prove by itself which part has failed.
Whether E10 coincides with extreme cold
- Who:
- you.
- How:
- note the outdoor temperature and whether the alert came during a freeze. Also check whether the code is E296: Google handles E296 separately and asks you to check the battery level.
- Result that matters:
- whether E10 lines up with very low temperatures.
- If it does:
- this fits the AC cold weather shutoff; Google's quick fix may get your heat back.
- If it isn't extremely cold:
- a system fault is more likely and you should call a professional now.
- Evidence to keep:
- date, time, outdoor temperature and photo of the code.
Evidence: Troubleshoot E10, E30, E66, E80, E116, E160, E196, E296, M13, N262, N263, N412, and N413 help codes
Thermostat battery with E10 or E296
- Who:
- you.
- How:
- if the thermostat won't turn on, charge it through the USB port on the back of the display for 5 to 10 minutes, or replace both AAA batteries if your model uses them, as Google says.
- Result that matters:
- whether the thermostat powers up and lets you turn on heat.
- If it powers up:
- you have control while waiting for the professional, but the power problem remains.
- If it stays off:
- don't go further and call a professional.
- Evidence to keep:
- photo of the display after charging or replacing batteries.
Evidence: Troubleshoot E10, E30, E66, E80, E116, E160, E196, E296, M13, N262, N263, N412, and N413 help codes
Google's quick fix to get heat back
- Who:
- you only if you can follow the guide exactly; otherwise a professional.
- How:
- with system power off at the breaker, photograph the wiring, remove the Y wires (Y, Y1 or Y2) from the base and, if you have both Rc and Rh, those too; wrap each end in electrical tape, refit the display and restore power.
- Result that matters:
- whether the thermostat powers up without an alert and heat can be turned on.
- If it starts without a code:
- you have heat, but the AC won't work until Y1 is reconnected with a C wire installed.
- If it still won't start or shows a code:
- put the wires back as in the photo and call a professional.
- Evidence to keep:
- photo of the wiring before touching anything and of each taped wire.
Google requires turning power off and testing that it is off before disconnecting wires, and taping each end to avoid short circuits. Only the thermostat base is touched, never the equipment.
Evidence: Troubleshoot E10, E30, E66, E80, E116, E160, E196, E296, M13, N262, N263, N412, and N413 help codes
Still not solved
If the error persists, stop here. See what the technician must do and show you.
Where this code applies
A code is meaningful only inside the right product and version context.
Primary scope
- System
- HVAC
- Brand
- Google Nest
- Product type
- Smart thermostats
Known code variants
- 0x9002
- 3FE-8314IT E10
- 4FE-7612 E10
- Airfryer E10
- Bongo E10
- Bongo scooter error E10
- Bongo serie V comunicación pantalla
- Bongo V series display communication
- Bongo V55 E10
- Bongo V70 E10
- Cecotec scooter error E10
- Código de error E10
- E 10
- E-10
- E10
- E10 Airfryer
- E10 cold weather shutoff
- E10 error tado
- E10, 0x9002
- Error code E10
- Error E10
- error E10 lavadora Fagor
- error E10 tado
- Fagor E10
- Fagor washer E10
- Fagor washing machine E10
- lavadora Fagor E10
- Nest E10
- Nest E116
- Nest E160
- Nest E196
- Nest E296
- Nest E30
- Nest E66
- Nest E80
- Nest thermostat E10
- patinete Bongo error E10
- patinete Cecotec error E10
- sensor de temperatura tado E10
- tado E10
- tado Smart Thermostat E10
- tado thermostat E10
- tado wireless temperature sensor E10
- tado° E10
- termostato Nest E10
- termostato tado E10
What it means
Without a common wire, a Nest can power itself through the Y1 (air conditioner) wire. If the AC stops sending power, E10 or an equivalent appears. Google lists two possible reasons: the system needs maintenance, or an AC safety device (low pressure switch or safety cutout) stops it starting in very low temperatures. Google stresses that a professional must diagnose the root cause: the code doesn't identify it.
Warnings and stop conditions
- Highsource verified
After the quick fix the air conditioner won't work until the Y1 wire is reconnected; don't forget it before summer.
Evidence: Troubleshoot E10, E30, E66, E80, E116, E160, E196, E296, M13, N262, N263, N412, and N413 help codes
- Mediumsource verified
A disconnected wire left untaped can touch another and cause a short circuit that damages the thermostat or the equipment.
Evidence: Troubleshoot E10, E30, E66, E80, E116, E160, E196, E296, M13, N262, N263, N412, and N413 help codes
Symptoms and causes
Probable causes · in order
- AC cold weather safety shutoffCommon
A low pressure or safety cutout switch stops the AC starting in extreme cold and it stops powering Y1. Fits if it coincides with a cold snap.
Evidence: Troubleshoot E10, E30, E66, E80, E116, E160, E196, E296, M13, N262, N263, N412, and N413 help codes
- HVAC system needs maintenancePossible
If the system breaks down it stops sending power to the thermostat. Fits if the code appears without extreme cold.
Evidence: Troubleshoot E10, E30, E66, E80, E116, E160, E196, E296, M13, N262, N263, N412, and N413 help codes
- Thermostat without a C wire relying on Y1Common
The underlying cause is that the Nest has no dedicated power. Google recommends a common wire or the Nest Power Connector to stop it recurring.
Evidence: Troubleshoot E10, E30, E66, E80, E116, E160, E196, E296, M13, N262, N263, N412, and N413 help codes
Virtual technician
Does E10 still appear after these checks?
Answer a few questions to narrow down the likely cause and the safest next action. Guidance only - it never replaces a professional.
Sources and technical references
- 1
Troubleshoot Nest thermostat help codes
Google · 2026 · official_doc
- 2
Troubleshoot E10, E30, E66, E80, E116, E160, E196, E296, M13, N262, N263, N412, and N413 help codes
Google · 2026 · official_doc
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