If your LMU-4200 Series device seems to be failing, before contacting CalAmp about returning it, first try the following troubleshooting steps to make sure that something else other than the hardware isn't causing the problem:


  1. Make sure that the vehicle has a clear view of the sky.
     
  2. Check that the vehicle ignition key is in the ON position.
     
  3. Check the status LEDs:
      
    • Ensure that the COMM LED is solid orange. This is what the LED states indicate:
       
      Condition
      		COMM LED (Orange)
      Modem off
      		Off
      COMM on - searching
      		Slow blinking
      Network available
      		Fast blinking
      Registered but no inbound acknowledgment
      		Alternates from solid to fast blink every 1 second
      Registered and received inbound acknowledgment
      		Solid

       
    • Ensure that the GPS LED is solid yellow/green. Here is a description of its LED behavior:
       
      Condition
      		GPS LED (Yellow/Green)
      GPS off
      		Off
      GPS on
      		Slow blinking
      GPS time sync
      		Fast blinking
      GPS fix
      		Solid
       
  4. Check that the antenna connections are secure and have a clear view of the sky, plus the following:
     
    • Make certain that the antenna is damage free.
       
    • Test a spare antenna and hold it outside of the vehicle. The COMM and GPS LEDs should lock on solid within three minutes. If the new antenna connects, replace the nonfunctioning one with the spare.
       
    • Verify that the wire is not cut or kinked from the GPS unit all the way to the antenna.
       
  5. Verify that the wiring connections for power, ground, and ignition are not loose or broken:
     
    • Red wire to a constant (unswitched) +12 VDC or +24 VDC supply – preferably, connected directly to the vehicle battery terminal or as close to it as possible. This connection point should be fuse-protected to not more than 5 amps.
       
    • White wire to the vehicle ignition.
       
    • Black wire to chassis ground.
       
    • Verify that the fuses are in place and are functional.
       
  6. Verify that the LMU (location messaging unit) is reporting to CalAmp K-12:
     
    • Open the CalAmp K-12 mobile app, which is available in Google Play or the App Store, on a mobile device. In the vehicle list, tap the vehicle name. (See Tracking a Vehicle for more details.) If the LMU is reporting live, a map will appear showing the bus's location. Below the map, check the number to the right of Sats (the GPS satellite count); make sure that it is 5 or higher. Also check to the right of Event. Make sure that this reads Ignition On when the vehicle is running and Ignition Off when it is off.
      Note: You'll need to log in to the app using a CalAmp K-12 login, not a punch ID.
    • On a computer, use CalAmp K-12 (https://login.synovia.com) to check whether any events are being reported for the vehicle and that it appears in its current location on the map. (See Tracking a Vehicle for more details.)
       
  7. If step 6 shows that the bus still isn't reporting data to CalAmp K-12, try swapping out the nonfunctioning LMU for a known working LMU, just to check for certain whether the device is the problem.
     
    If data is being received from the LMU but you are still having issues, try troubleshooting any peripheral devices. (For example, see MDT-8W Troubleshooting Steps, MDT-8M Troubleshooting Steps, or MDT-7P Troubleshooting Steps.)


If you've tried all these troubleshooting steps and the device is still malfunctioning, you can open a ticket at CalAmp K-12 Support Portal. (You can find more details at Returning Hardware and Obtaining a Replacement [Performing an RMA].)