*Can't Pair With Connect Kit

You NEVER try to pair with the kit from your device's Bluetooth menu.  Just open JB4 Mobile and hit the connect button.  Follow any on-screen prompts to finish the connection process.

*No BLE Devices Found

Double check the power wire and DB9 installation.

Disable BT and Wifi.
Restart Device.
Enable BT.
Try again.
Does the error remain?

If you are using Android, ensure Location Services are enabled for JB4 Mobile and that you have given it all the required permissions.

If you still have issues email us at

*Error Connecting To JB4

Try disconnecting then reconnecting the DB9 plug.  If that doesn't work it's either an issue with the kit or JB4.  You'll need to find another kit/BMS USB cable to test with or send the kit to me for testing.  Email me ( and let me know that you've performed the diagnostics mentioned for this error.

*Kit Not Owned

Email me:

Include a screenshot of the error message showing the kit address.

*None of my gauges are working:

1) Make sure your JB4 isn't on map 0.

2) Kill and restart the app.

3) Take a log and see if you're getting any readings.

4) Ensure your CAN wires or OBDII hookup is properly installed (it's usually this issue).

*My Oil Temp, Water, and/or Trans Temp gauges aren't working (applies to Trims 2, MPH/SPEED, Boost 2 also):

1) Does your engine type's JB4 support oil/water/trans temp?  If not, this feature doesn't work for you at this time (firmware limitation, nothing I can do about it).

2) If it does, is your firmware updated to the latest version that includes that functionality?

3) Ensure your CAN wires or OBD hookup is properly installed.

If you require further assistance, send an email to