My battery was low so I put 4 new ones in and it said batteries were low and temperatur -40

Are you using your device with ATLAS Weather Sensor?

Got it.
Just to make sure we're on the same page, the issue is that it's stuck on the temperature -40, correct?

Got it!
Could you please tell me, is the sensor is located away from sources of heat and moisture?

Good. Also, please make sure that the sensor is mounted at least 5 feet off of the ground or any other surface that may radiate heat. Roofing materials such as shingles or metals can radiate heat and affect the temperature readings of the device.

Very well. I am going to send you the instructions now, please make sure to complete them and let me know how it goes or if you have any additional questions.

Awesome! Here are the steps:

1. Please remove the batteries from the outdoor sensor.
2. On the bottom of the sensor, there is a vent cover that is held in place by 2 tabs. Remove the vent. Under the vent, there is a cylinder that is clipped in with 2 tabs. This is the temperature and humidity sensor. Remove the temperature and humidity sensor to expose the fan.
3. Unplug the white cable connector and wait 20 seconds then plug the temperature and humidity sensor back in. This will reset the temperature and humidity readings.
4. Install the temperature and humidity board over the fan assembly, and confirm the tabs do not block the fan from spinning.
5. Reinstall the batteries in the sensor. Confirm the red light near the battery compartment door flashes every 10 seconds.

Sure, appreciated :)

I’m glad I was able to get that sorted out for you. Is there anything else I can assist you with today?