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GPS Unit Troubleshooting

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No Recent Last Phone Home

GPS Units normally phone home every four hours and update the Last Phone Home field in the GPS Units Report on Ground Traffic Control. If a GPS Unit is not phoning home regularly, it most likely has one of the following issues:

  1. GPS blockage
  2. Cellular issues
  3. Constant power and/or ground

It is recommended to perform an LED light status check on any asset not phoning home. The following article may help with troubleshooting specific LED statuses.

When the engine is running, allow 2-3 minutes for the LEDs to stabilize.

When the vehicle’s engine is turned off, the three green LEDs will begin to blink for a short period of time. If all LEDs extinguish immediately after the engine is turned off, contact Zonar (877-843-3847).

There are no LEDs displaying

  • The GPS Unit is sleeping. If this is the case, there is no issue. To check that the unit is sleeping, start the engine and ensure that all of the LEDs illuminate.
  • Cables were connected out of sequence.
    Solution: Disconnect the 4-pin connector from the back of the GPS Unit and wait for 30 seconds before reconnecting the 4-pin connector.
  • The vehicle’s Master Kill switch or battery disconnect switch was set to “Kill.”
    Solution: Turn the Master Kill switch to “Live” to supply power to the vehicle.

    It is preferred to have GPS Units wired outside the Master Kill circuit so that the GPS Unit can send diagnostic information during off-duty periods.

  • The vehicle’s electrical system malfunctioned.
    Solution: Check for a dead battery, loose or corroded terminals, bad crimps or solder joints, etc.
  • Blown or missing fuse in the power/data cable.
    Solution: Replace the fuse.
  • The vehicle uses a Multiplex wiring system and has put the circuit to sleep.
    Solution: Rewire the unit outside of the Multiplex circuit.
  • The vehicle’s JBus port is miswired or does not always supply constant power or the constant power lead is not connected to a constant power supply.
    Solution: Check the voltages at the JBus connector or constant lead terminal.
  • There was an equipment or cable malfunction.
    Solution: Test with known good vehicle, equipment, or cable.

 

All LEDs go out when the engine is turned off

The JBus port was likely miswired or the constant power lead is not connected to a constant power supply. To resolve this, check the voltages at the JBus connector or constant power lead terminal.

 

GPS light continually blinks

  • GPS signal is not available.
    Solution: Move away from the area with blocked signal (typically a garage or covered parking area). Also, check the GPS antenna cable and system if an external antenna is in use.
  • There is an equipment or cable malfunction.
    Solution: Test the GPS Unit in a known good vehicle or a known good GPS Unit in the affected vehicle.
  • Orange LED indicates that the internal GPS antenna is in use.
  • Green LED indicates  that the external GPS antenna is in use.

 

Cellular light continually blinks or shuts off

  1. There is no cellular coverage in the area.
    Solution: Move the vehicle to an area with cellular coverage.

    If you are experiencing this issue with a GPS Unit located outside of the United States, it may not be set up for international roaming. Contact Zonar for further assistance (877-843-3847).

  2. The SIM (Cellular chip) is not activated.
    Solution: Verify with Zonar (877-843-3847).
  3. There is an equipment or cable malfunction.
    Solution: Test the GPS Unit in a known good vehicle or a known good GPS Unit in the affected vehicle.
    Carefully disconnect the 4-pin power connector from the back of the GPS unit, wait 30 seconds, and then reconnect the 4-pin power connector. If this corrects the issue (Cellular LED is now solid) contact Zonar and convey this information to Customer Care.

Status light continually blinks

This will not cause a delayed phone home, but the GPS Unit will not correctly track vehicle movement. Check that the unit is receiving proper ignition signal depending on type of installation used.

 

GPS/Cellular/Status LED lights are off, Datalink 1 and 2 rapidly flashing

Hardware malfunction that will require replacement. In most cases, Zonar can assist with returning the hardware via RMA.

 

Replacing GPS Unit

  1. Make sure the vehicle is located in an area with a clear view of the sky (for GPS signal reception) and with the engine off.
  2. In GTC, set the GPSID field of the asset to “None” and then click “save.”
    Manage > Assets > Assets > Select correct asset > Edit > Update GPSID field to “None” > Save.
  3. For non-OBDII installs, remove the GPS Unit from mount and remove the 4-pin power connector from the GPS Unit.

    For Zonar Light Duty (OBDII) installs, unplug the Zonar Light Duty cable from the vehicle’s OBD2 port.

  4. Remove all other cables from the GPS Unit.
  5. Using the GPSID from the back of the replacement GPS Unit, add to the GPSID field of the asset in GTC.
    Manage > Assets > Assets >Select correct asset > Edit > Update GPSID field to “GPSID of unit being installed” > Save.

    This step must be completed before continuing with the rest of the process.

  6. Connect all cables to replacement GPS Unit, except the 4-pin power connector.
  7. For non-OBDII installs, Connect the 4-pin power connector to the replacement GPS Unit.

    For Zonar Light Duty (OBDII) installs, start the engine before connecting the Zonar Light Duty cable into the vehicle’s diagnostic port.

  8. Start the vehicle’s engine. The GPS, Status, and GSM/Cellular diagnostic LEDs should all be solid green within two minutes.
  9. Turn off the engine. The Status LED should begin to blink (disregard the other LEDs).

If not connected to Diagnostics (4pin, 3-4 wire install):

  1. Record the odometer and engine hour values.
  2. Enter the odometer and engine hour values in GTC.
    Odometer: Reports > GPS Track and Trace > Odometer > Odometer Offsets Admin.
    Engine Hours: Reports > Fuel, Diagnostics, and Usage > GPS Engine Hours > Admin Hobbs Meter.

Non-Existent GPS Engine Hours

There are three possible reasons for less than expected or non-existent GPS engine hours:

  • A cold start occurred while the engine was running.
    Solution: Resolve the cold start issue.

  • Master Kill or Master Disconnect switch was activated prior to Zonar uploading trip data.
    Solution: Wait for the green status LED to go from a double blink to a single blink before activating the Master Kill switch. If this does not work, wire the Zonar GPS Unit outside the Master Kill switch.

  • The constant power was lost at an engine-off event.
    Solution: Ensure constant power is not lost at an engine-off event. See the GPS Unit’s specific instructions on how to identify and diagnose this issue. Losing ALL GPS LEDs at an engine-off event is usually indicative of:
    Constant/red power lead not connected to a source of constant power.
    A JBus 6- or 9-pin diagnostic port (vehicle side) loses power at an engine-off event.

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