nest protect sensor failure

Are you experiencing Nest Protect sensor failure? Well, the solution is really simple!

Nest Protect sensor usually fails due to accumulated dust or debris, leading to a wrong action such as producing sounds when there is no smoke.

Then the Nest app will show the “Sensor Failure” message which is a prime indication that it’s cleaning time!

Let’s unwrap more about the reasons why the sensor fails!

Causes For Nest Protect “Sensor Failure”?

  1. Build up of dust and debris on the sensor
  2. Outdated firmware of the Nest Protect app
  3. Battery issues or loose device wiring
  4. Exposure to high temperatures or humidity
  5. Physical Damage or malfunctioning sensor
  6. Damage due to water intrusion or steam
  7. Power surges or AC-related power issues

Signs of Nest Sensor Failure!

signs of nest failure
  • Nest Protect produces false smoke alarms.
  • The Nest app shows a Sensor Failure message.
  • Nest Protects chirps continuously.
  • Protect will show a yellow ring while Nightly Promise. 
  • Nest will produce a Heads-Up alert. 
  • A Yellow Light when pressing the Power Button.

Nest Protect Sensor Failure Fix – (Easy Solutions)

Tip: Don’t skip any of the steps for optimal troubleshooting!

1. Restart The Nest Sensor

Sometimes due to electrical or technical glitches, the Nest Protect sensors detect wrong and do inappropriate actions.

Therefore, restart the Nest Protect, since the power cycle will easily solve and eliminate all bugs and glitches from the device.

restart nest protect

Here is how to restart the Nest Protect:

  1. Get access to the Nest Protect detector.
  2. Locate the ON/OFF power button on the device.
  3. Ensure to set the protection to the OFF position.
  4. Next, press and hold the Nest button for 10 seconds.
  5. Release the button as the Protect glows a blue ring light.

In case the “Sensor Failure” message does not disappear after the restart, keep reading!

2. Clean The Nest Protect Detector

Over time, dust accumulates over the Nest Protect and sensors and causes them to malfunction thus, here’s the reason why the device detects wrongly.

Therefore, clean the Nest Protect and check if the sensor is functioning normally when you’re done!

clean nest protect

Here is how to clean the Nest Protect in easy steps:

  1. Turn off the Nest Protect and rotate the detector counterclockwise.
  2. Remove the device from the wall and clean the outside of the panel.
  3. Tip: Use a soft brush to clean the detector and always avoid liquids
  4. Next lay down the Nest Protect on the soft and dry cloth facing down. 
  5. Open the Nest Protect battery compartment and eject the batteries.
  6. Take out the batteries and unscrew the screws located underneath.
  7. Next, vacuum or clean the inside of the device using compressed air
  8. Make sure to clean the smoke metal chamber and screw the cover.
  9. Insert the batteries, close the compartment, and mount the Nest detector.
  10. Clean the wall area of the Nest Protect location and fixate the bottom.
Info: Using any liquids ultimately leads to permanent Nest Protect device damage!

3. Initiate Self-Test On Nest Protect!

Now that the Nest Protect sensor has been restarted and cleaned, start the self-test on your Nest Protect sensor.

Your device will automatically self-test on the network and notify you of any issues via a sound or a prompt message.

The Nest device does a self-test after every 200 seconds and checks the device for battery, smoke sensor, Wi-Fi, and for Nest Protect carbon monoxide sensor failure.

As the device detects something wrong, it’ll alert you in Nightly Promise or you can manually hear and see.

How To Check Self-Test Results?

self-test nest protect
  1. To hear the results, press the Nest button.
  2. To observe the results, launch the Nest app.
  3. Tap on the Nest Protect, then on the “i” sign.
Note: A network connection is necessary on Nest Protect to initiate the self-test!

4. Check Nest Protect Wiring

Loose or defective wire connections in the Nest Protect detector device most often cause a different issue with the sensor detection.

That’s why it’s important to disassemble the Nest Protect from the base, inspect the wiring connections, and verify their orientation!

Here is how to check the Nest Protect detector’s wiring:

  1. Turn off the circuit breaker and the Nest Protect. 
  2. Hold the device and rotate it counterclockwise.
  3. Then remove the panel from the device’s base.
  4. Note down the wire’s connections (take an image).
  5. Then disconnect the wires from the connectors.
  6. Check the wires and connectors for any physical damage.
  7. (Tip) Use your product manual to verify the orientation.
  8. Then connect the wires and make sure to tighten them.
  9. Set up the device cover back and rotate it clockwise.
  10. Then turn on the power and circuit breaker to test.
Note: Reach out to a professional for repair if you found any defect in the wires or connectors!

5. Change The Nest Protect Place

change place of nest protect

Humidity and high temperature may often impact the sensor negatively and result in faulty detection.

If your Nest Protect sensor is placed close to a bathroom, humidifier, or kitchen, then this may be the cause of the device’s sensor failures.

  • Install the Nest Protect somewhere else far from steam or moisture areas!

The best place for a Nest Protect sensor would be near the bedroom, so you can be woken up and alerted even when sleeping.

This is why the majority of users prefer to install the device in front of the bedroom door or in the hallway near the bedroom.

6. Check For Firmware Updates

When Nest Protect is running under outdated software, it often experiences different issues with the device.

Check for a Nest Protect firmware update, update it if possible, and then see if the sensor is functioning properly.

  • Connect your Nest Protect to Wi-Fi to upgrade the firmware version!

If your device is already connected to the network and hasn’t updated the firmware, then there might be a connectivity issue with Nest Protect.

Therefore, reset the network connection on Nest Protect and then check if the firmware upgrades.

firmware updates for nest protect

How To Reset Nest Protect Network Connection?

  1. Tap the Nest button from the device one single time.
  2. Wait until the device says, “Ready” or how in the app.
  3. Next, press and hold the Nest button for 5 seconds.
  4. Wait until the device says, “Checking the network.”
  5. Then wait for about 15 minutes and remain patient. 
  6. Leave the device to reset and update the firmware.
  7. After that, check Nest Protect’s firmware version.

7. Inspect The Protect Batteries Charging!

It’s also important to check the batteries in your Nest device and make sure they are charged and are not near the end.

Otherwise, if you haven’t changed the batteries in the device for a long, then replace them because maybe low batteries are causing the sensor to malfunction.

Note: Always use Energizer Ultimate Lithium AA (L91) batteries for your Nest Protect!

Here is how to inspect the Nest Protect batteries charging:

  1. Turn on the Nest Protect detector.
  2. Launch the Nest app on your mobile.
  3. Tap on the Nest Protect device.
  4. Check the Battery Level on the screen.
  5. If the batteries are low, then replace them.

Replacing the batteries in Nest Protect may vary from generation to generation and that’s why check the product manual for the correct steps!

8. Factory Reset The Nest Protect

factory reset nest protect

If the sensor isn’t functioning normally after following the aforementioned methods, reset the Nest Protect detector.

This is the most powerful solution and will surely restore the original functionality of your Nest Protect detector.

Note: Nest Protect cannot factory reset by using Nest mobile app!

Here is how to *correctly* factory reset the Nest Protect sensor:

  1. Acquire physical access to the Nest Protect.
  2. Locate the Protect button on the device panel.
  3. Press and hold the Protect button for a while.
  4. In the meantime, the device will chime and glow blue.
  5. Release when the device narrates the serial number.
  6. Then it’ll automatically start a countdown for the reset.
  7. Wait until the reset process ends and set up the Nest app.

The reset shouldn’t take too long but make sure not to interrupt the process before finishing!

Note: If the Nest Protect sensor continues to appear, then contact Nest Support for help.

Quick Recap:

To fix the Nest Protect sensor failure, restart the device, clean the sensor, and then initiate the self-testing to learn more about the issue.

Also, check the device wiring, replace batteries, move the device to another place, and perform a firmware update.

Read Next: Nest Protect Not Connecting To WiFi? Here’s How To Fix

Nicole B