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

Error code 103 is an error code displayed on Honeywell ADT keypads when there is a problem with cellular or Internet communications. In most cases, it is a problem with the cellular connection.

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

The 103 error code displays when there is a problem with cellular or Internet communications.

The ADT error code 103 means a problem with the control panel that your home security system uses. Fixing this problem is similar to fixing other codes, like 104 problems.

Several problems can cause a Check 103 or bF message to appear, mainly these are a loose tamper cover, the communicator is not registered or the communicator loses contact with the monitoring network.

What does error code “103 check lngrng radio” 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 typically on alphanumeric keypads for both ADT Safewatch Pro 2000 systems and ADT Safewatch Pro 3000 systems when they are 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.

The Error code 103 may also appear if the cellular radio loses the cellular signal.

This could be due to a temporary outage of your local mobile network, which can be just routine maintenance or general problems – but it could also a change to the environment (trees, buildings, construction, new roof or siding, etc.) that interfere with your signal.

Let’s get started.

Attempting to Fix ADT Error Code 103?

Step 1. Do test your system.

The first and most important step is to restore communication with your alarm system. Cell towers may have lost communication with your alarm system for a short period of time, but communication should now be restored.

You should contact ADT or your monitoring station to arrange for a test to be performed on your home surveillance system.

This is the simplest and most expedient solution. It is not necessary to restart your computer to remove the 103 error message if the test is successful. It will only take a few minutes to complete this task.

2. Turning the panel off and on

Secondly, another reason while many people get a code 103 is that their mobile device is no longer correctly registered (for whatever the cause it might be) with ADT correctly. So while everything looks normal from your side and from ADT’s side, there is still something not going well.

ADT’s support confirms (and this is also what they’ll tell you on the phone), to simply switch the panel off and on again completely, and this will solve likely your problem in 99% of the cases.

3. Check the strength of your signal.

Enter the installer code + 899 and the Lynx Plus will tell you the signal strength and whether it is registered or not:

  1. It displays a message saying that it is in programming mode.
  2. It displays the signal strength.
  3. If it displays “POOR” or “FAIL”, you need to move the control panel to a place with a stronger signal.

Signal strength between -94dBm and -20dBm is required.
If the signal strength is between -95dBm and -120dBm, the radio will operate poorly or not at all.

How can this happen if it was working correctly you might wonder? Objects inside or outside the house might be interfering suddenly.

Just take off and walk with it around the house, both inside and outside. This will help you find the ideal spot and where the location has a strong signal.

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.

What is the procedure for resetting my ADT alarm code?

Instructions for changing the user codes in the ADT system by the use of the keyboard:

  1. To indicate that you want to reprogram a phone number, press the asterisk followed by the number 5.
  2. Enter the four- or six-digit master code number that you were given.
  3. By inputting the numbers 01 through 32, you can choose the User Access Code you want to modify.

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.