How to Fix ADT Error Code 103 (Fast + Video)

Check 103 is an error code that displays on Honeywell ADT keypads when there is a problem with cellular or Internet communications. In most cases, it is a cellular communication problem. So, if you’ve been looking for the best solution to ADT error code 103, you’ve come to the right place.

We have put together a short and simple guide on how to fix ADT error code 103.

ADT error code 103 means a problem with the control panel that your home security system uses. Fixing this problem is the same as fixing any other code 104 problems. A few different things can cause ADT code 103 problems:

Remember that many problems can cause a Check 103 or bF message to appear. These include a loose tamper cover, the communicator is not registered, and the communicator loses contact with the monitoring network.

What does code 103 mean on ADT?

The ADT error code 103 is usually caused by a lapse in the Honeywell ADT communicator. For example, the message “103 checks lngrng radio” on your ADT system means a problem with the system backup communicator.

The message appears on an alphanumeric keypad for an ADT Safewatch Pro 2000 system or an ADT Safewatch Pro 3000 system experiencing communication problems.

If you get the message “Check 103 Long Range Radio” on your Honeywell ADT keypad, it means there is a problem with the mobile communicator connected to your system.

A severe drop in signal strength could cause the problem.

Check 103 may appear if the cellular radio loses the cellular signal. This could be due to a temporary outage of your local GSM network. It could be just routine maintenance or general problems. It could also change the environment (trees, buildings, construction, new roof or siding, etc.).

Attempting to Fix ADT Error Code 103?

Step 1. Test the system

There is a chance that the cell towers have lost communication with your alarm system once, and now you have restored the alarm communication. We recommend that you call ADT or your central station to perform a test.

If the test is successful, control 103 will disappear.

Step 2. Power cycle

There is also a chance that your mobile radio is no longer registered for some reason. So check your signal strength.

There is a small chance that you don’t have good signal strength. However, if you know the installer code, you can enter installer code + 899, and the Lynx Plus will tell you the signal strength and whether it is registered or not. It will first say that it is in programming mode.

Then it will display the signal strength. If “POOR” or “FAIL” is displayed, move the control panel to a location with better signal strength. You must have a signal strength between -94dBm and -20dBm. If you have -95dBm to -120dBm, the radio is not working very well.

You can always remove the unit and go in and out of the house and see if the signal is better in one place than another.

How to Fix the ADT error code 103 Step by Step

To successfully fix the ADT error code 103 yourself without external help, follow the steps below.

  1. Firstly, Put the system into test mode
  2. Enter your master code and type 5
  3. Open the ADT keypad
  4. Disconnect the white cable from the circuit board for 20 to 30 seconds
  5. Connect the white cable back to the circuit board
  6. Close the keypad
  7. Enter your master code into the keypad
  8. Press the “Off” button two times

Now, check again. The ADT error code 103 should disappear by now.

How do I reset my ADT alarm code?

To change the user codes in the ADT system with keypad control:

  1. Press the asterisk and then the number 5 to indicate that you want to reprogram a number.
  2. Enter your four or six-digit master code number.
  3. Select the User Access Code you want to change, identified by entering 01 through 32.

Tutorial Video (fast!)

Wrapping Up…

Having established that the error code 103 that shows up on Honeywell ADT control panels resulted from a cellular or internet communication problem, we also offered some step-by-step guide on fixing ADT error code 103.

However, If resetting the system didn’t fix your problem, please contact your alarm monitoring company.