*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

Try disabling then reenabling Bluetooth on your phone/tablet.

Verify that the install location of the power wire is correct for your engine type.

Disconnect then reconnect the DB9 plug.

If you still have this error after the 3 steps above, email me ( and let me know you performed the 3 diagnostic steps.

*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 OBD 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