Fix a Comm Failure Alert from your Xfinity Home sensor

Learn what to do when you get a Comm Failure Alert for your Xfinity Home Door and Window or Motion Sensor.

You will need:

Xfinity Home Security or Smart Home service.
Access to your touchscreen or the Xfinity Home app if you have Xfinity Home Security.
Access to the Xfinity app if you have Xfinity Smart Home.
Access to your Xfinity Home Sensor.

Difficulty

Easy

Finding the problem

When your touchscreen or mobile app shows a Comm Failure Alert for a door/window or motion sensor, it may mean the sensor has stopped working right and needs troubleshooting. This can happen even after you change the batteries.

If you just changed the batteries, the most common reason a sensor stops working is the tamper switch was accidentally touched.

Find the LED light on your sensor.
- Door/window: The light is found on the large part of your sensor. It's most often attached to the door or window frame. Find your sensor below.
- Motion: The light is found on the circuit board or near the batteries. Find your sensor below.
Activate the sensor.
- Open the door or window.
- Motion sensors activate when the cover is removed.
If the light blinks three times, pauses, then continues blinking in the same pattern, the sensor is not working right and needs to be serviced. Contact us.
If the LED does not light, you may need to remove and reinsert or change the batteries.

Leedarson LDHD2AZW

The light on the Leedarson LDHD2AZW is located on the long smooth front surface, toward the top beveled edge.

Sercomm XHS2-SE, Tyco XHS2-TY (MCT-350), or UEI XHS2-UE

The light on the Sercomm XHS2-SE, Tyco XHS2-TY, or UEI XHS2-UE is located on the wide smooth front surface, toward the top beveled edge.

Sercomm SZ-DWS04

Remove the cover to find the light for this model. Steps to remove and replace are in the battery installation guide.

The Sercomm SZ-DWS04 with the cover removed contains the light in the lower left corner, near the rounded edge and below the diamond shaped object in the middle.

SMC SMCDW01-Z or SMC SMCDW02-Z

The SMC SMCDW01-Z or SMC SMCDW02-Z light is along the long, slightly rounded surface a little more than halfway down.

Visonic MCT-320 SMA

The Visonic MCT-320 SMA light is on the side of the crescent shaped cutout on the widest rounded surface.

Visonic MCT-340 SMA

The Visonic MCT-340 SMA light is in the center of the longest surface, just above the cover seam.

Motion sensor light locations

SMC SMCMT01-Z
SMC SMCMT03-Z
Visonic CLIP SMA
Visonic NEXT K85
XHS1-TY
XHS1-UE
UEHM2AZ0/H74470BA00-0004

SMC SMCMT01-Z or SMC SMCMT03-Z

Remove the cover to find the light for these models. Steps to remove and replace are in the SMCMT01-Z and SMC SMCMT03-Z battery installation guides.

The SMC SMCMT01-Z or SMC SMCMT03-Z light is to the left of center, just below the raised edge.

Visonic Clip SMA

Remove the cover to find the light for this model. Steps to remove and replace are in the battery installation guide.

The Visonic Clip SMA light is in the top right corner, opposite of the battery.

Visonic NEXT K85

Remove the cover to find the light for this model. Steps to remove and replace are in the battery installation guide.

The Visonic NEXT K85 light is inside the cover on the bottom left, closer to the short edge of the inside.

XHS1-TY, XHS1-UE, or UEHM2AZ0/H74470BA00-0004

Remove the cover to find the light for this model. Steps to remove and replace are in the battery installation guide.

The XHS1-TY or XHS1-UE light is inside the removed cover, to the left of the batterie near the diagonal edge.

Additional information

Visit our Online Support Center to find common solutions.

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Fix a Comm Failure Alert from your Xfinity Home sensor

Finding the problem