ADT's status indicators article explains what the app and Base show. The dashboard displays the current arming mode, and an alert icon with a number shows the issues preventing full arming, such as an open door or window, a device with a low battery or a missing sensor that is offline or disconnected; tap it for the list of trouble devices.
The checks in more detail
The Base's LED bar shows states: dark with a green Disarmed button when ready, solid blue for two seconds then fading with the mode button blue when armed Away, Stay or Night, blinking red with an emergency icon in an alarm, dark with a solid yellow Disarm button when a device is faulted, lost or low on battery, blinking blue in pairing mode and green when connected to a sensor, purple while downloading firmware, and green when fully connected. A stale status can mean the Base lost its connection, a sensor is offline or a battery is low.
Refresh the app, read the Base LED, check the offline and low battery articles and clear the trouble. Time on events follows your phone and location. After a power outage the Base needs a few minutes to reconnect. If status stays wrong, contact ADT chat with a screenshot and the LED pattern. Photograph the app and the Base LED together so any mismatch is clear. A status that flips is a connection problem. Contact support with screenshots.
The number on the alert icon counts issues, not devices, so one device with two issues shows a two. The Base's yellow Disarm button means a device is faulted, lost or low on battery, and it may come with trouble beeps, so listen as well as look when the status seems wrong. Take a screenshot of the alert icon's list before you start fixing things, so you can confirm each item clears in turn.
Differential
Likely causes of “ADT Base shows the wrong time, state or sensor reading”, and how to tell them apart
- 1
An open door or window
What separates it An alert icon with a number appears on the dashboard because a door or window is open
How to confirm Close the open door or window so the system can arm and the alert clears
- 2
A low battery
What separates it A yellow Disarm button shows because a device in the system has a low battery
How to confirm Replace the battery in the device named in the trouble list and check the button changes
- 3
A missing sensor
What separates it A device shows as offline in the list because a sensor has gone missing from the Base
How to confirm Reconnect the sensor or remove it and add it again, so the Base reports its status properly
- 4
A lost connection
What separates it The status in the app is old and does not change because the Base has lost its connection
How to confirm Restore the wifi and cellular connection so the Base can send fresh status to the app
- 5
A power outage
What separates it The status looks stale after a power cut because the Base has not yet reconnected to its services
How to confirm Wait for the Base to reconnect, which can take a few minutes, and refresh the app
Before you touch a setting
Record this first — changing settings destroys the evidence
- The number shown on the alert icon and what the trouble list says
- The Base LED color and pattern
- The trouble list shown in the app
- A screenshot of the screen that shows the wrong information
Try in this order
0 of 7 completedRead the alert icon
ReversibleRead the alert icon and tap it for the list, which names each issue that is stopping the system from arming fully and where it is.
Read the Base LED
ReversibleRead the Base LED and note its color and pattern, because ADT uses them to show power, network and update states at a glance.
Fix each trouble
ReversibleFix each trouble in turn, whether it is a door, a battery or a sensor, and check that the alert count goes down as you do.
Refresh the app
ReversibleRefresh the app so that it shows the latest status from the Base, since an old screen can show a problem that has already been fixed.
Wait after a power cut
ReversibleWait a few minutes after a power cut, because the Base needs time to restart its services and reconnect before the status is right.
Check the time zone
ReversibleCheck the time zone on the phone and on the account location, because a wrong time zone makes events show at the wrong time.
Contact ADT
ReversibleContact ADT with a screenshot if the wrong status remains, so the support team can see exactly what the app is displaying.
Model-specific
What is true of this model and not of its siblings
- LED
- Shows arming, alarm, pairing and update states.
- Alert icon
- Counts issues blocking arming.
Stop boundary
When this stops being a self-service repair
- !If status stays wrong, contact ADT through chat
- !If a device is missing, follow the offline article
- !If a battery is low, replace it soon so the device does not drop off the system
Evidence ledger
Sources behind this answer
Base setup and placement.
Base LED patterns.
Offline meaning and fixes per device.
Battery types and lives.
AC power and backup battery.
The company and its products.
Exact questions
Common questions
What does the alert icon mean?+
The alert icon shows the number of issues that are preventing the system from arming fully, such as an open door or a device with a low battery.
What does a yellow Disarm button mean?+
A yellow Disarm button means a device in the system is faulted, lost or has a low battery, so check the trouble list to find out which.
What does purple mean?+
A purple Base LED means firmware is downloading, so leave the Base powered and connected until it has finished.
Can the app be stale?+
Yes, the app can show a stale status if the Base has lost its connection, so refresh it and check the Base connection if it looks wrong.
Should I check the LED?+
Yes, check the LED on the Base too, since it shows the state of the Base itself even when the phone app is out of date.
How do I clear an alert?+
To clear an alert fix the issue that caused it, for example by closing the door or replacing the battery, and it clears by itself.
What is the ADT Base model?+
The current ADT Base is model ADTBASE502R0, which is the number to quote when you contact ADT about the Base.
Does the Base include a keypad?+
Yes, the Base has a built-in keypad on top, so you can arm and disarm the system directly at the Base without a separate keypad.