A door and window sensor tells your alarm one thing, whether the two halves of the sensor are together, and nearly everything that looks like a wrong status comes from that fact. If the app says a door is open when it is shut, the transmitter and its magnet are too far apart or misaligned, perhaps because the door has swollen in damp weather, a hinge has sagged or the frame has shifted. Open the door, close it and watch the app; if the status follows the door, the sensor works, and the gap needs adjusting. Stick the parts in place with the tape ADT supplies, in the positions on the instructions, and test them.
The checks in more detail
A magnet fixed to the door and the transmitter to the frame, with the marked edges facing, is the arrangement to use. If the status is late, not wrong, the radio link or the battery is the cause. The sensor sends a report when the magnet moves, and a weak battery makes it slow or unreliable, so replace it with the type ADT lists. A panel that is far away or behind metal hears the sensor late. Move the panel closer to the center of the house and away from large metal objects, and keep other radios, such as a router, a few feet away.
For an event time that is hours out, check the system's time zone in the ADT app and the phone's automatic time, since the sensor stamps nothing itself.
Test in the app's test mode by opening and closing the door several times and noting the times. Sensors on a door that is used all day fail sooner than those on an upper window, so inspect them each year and replace the batteries before they fail. If a sensor keeps misreporting after the gap, battery and range are right, remove it from the system and add it again, or contact ADT with its model. Do not disable a sensor to stop false alarms; adjust or replace it. A door or window sensor from ADT sends a message to the panel when the magnet moves away, and the time that appears in the app or the history comes from the panel or from the ADT servers, not from the sensor itself.
A wrong time therefore points to the panel's clock or the app's time zone setting, and not to the sensor. Check the time zone in the app and on the panel, and whether the panel has daylight saving enabled. If the panel lost power or its connection for a while, the clock may have reset, and it corrects itself when it reconnects. A status that stays on Open when the door is closed is a different problem, usually a magnet that has drifted too far from the sensor: the gap is typically small, and the two parts should line up on the marked sides. Replace a weak sensor battery too.
Differential
Likely causes of “ADT Door/Window Sensor shows the wrong time, state or sensor reading”, and how to tell them apart
- 1
A magnet gap that is wrong
What separates it The sensor shows open when closed
How to confirm Realign the magnet and sensor
- 2
A weak battery
What separates it Late or dropped reports
How to confirm Replace the battery
- 3
A warped door or frame
What separates it The gap changes with the weather
How to confirm Adjust the sensor position
Before you touch a setting
Record this first — changing settings destroys the evidence
- The device's state in the app
- The battery or power
Try in this order
0 of 2 completedMove the panel closer
ReversibleIf reports are late.
Re-add the sensor
ReversibleOr contact ADT.
Model-specific
What is true of this model and not of its siblings
- Two parts
- A transmitter and a magnet.
- Time source
- The panel and the service, not the sensor.
Stop boundary
When this stops being a self-service repair
- !If the problem persists after these steps, contact ADT with the device and system details
- !Do not disable a safety device
Evidence ledger
Sources behind this answer
Exact questions
Common questions
Should I disable the sensor?+
No, fix the cause.
Why does the sensor say open when closed?+
The magnet may be misaligned.