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.

What you'll need:

Xfinity Home Pro Protection or Self Protection
Access to your touchscreen or the Xfinity Home app if you subscribe to Pro Protection
Access to the Xfinity app if you subscribe to Self Protection
Access to your Xfinity Home Sensor

Difficulty

Easy

Determining the problem

When your touchscreen or mobile app displays a Comm Failure Alert for a door/window or motion sensor even after you replaced the batteries, it may indicate that the sensor has stopped working properly and requires troubleshooting.

Did you know? If you just replaced the batteries, the most common reason a sensor stops working is when the tamper switch is accidentally touched while changing batteries.

Find the LED light on your sensor.
- Door/window: The light is located on the large part of your sensor; the part usually attached to the door or window frame. Find your sensor below.
- Motion: The light is located 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 correctly and will need to be serviced. Contact us.
If the LED does not light, you may need to remove and reinsert or replace the batteries.

Door and sensor light locations

Leedarson LDHD2AZW
Sercomm SZ-DWS04
Sercomm XHS2-SE
SMC SMCDW01-Z
SMC SMCDW02-Z
Tyco XHS2-TY
UEI XHS2-UE
Visonic MCT-320 SMA
Visonic MCT-340 SMA

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, 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. Instructions for removing and replacing are included 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. Instructions for removing and replacing are included 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. Instructions for removing and replacing are included 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. Instructions for removing and replacing are included 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. Instructions for removing and replacing are included 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.

Fix a Comm Failure Alert from your Xfinity Home sensor

Determining the problem