JB4 Mobile Troubleshooting

1) Ensure the Connect Kit is as far away from nearby batteries/metals as possible as that can cause interference. You can also try standing directly next to the kit while attempting to connect. If standing closer to the kit RESOLVES the issue, email us at support@jb4connectkit.com and let us know you've performed the diagnostic steps already as this may indicate a range issue with your kit.

2) If you changed the PIN from the default '1234', ensure you've updated the 'Default PIN' field with the new PIN you set. If you didn't change the PIN, email into support@jb4connectkit.com. Include a screenshot of the error and let us know your username in JB4 Mobile.


Screenshot the error and email it to support@jb4connectkit.com.


1) Disable BT and wifi, restart device, enable BT, try again.

2) Check Connect Kit installation. Ensure positap is making a solid connection and that the DB9 connector is secured. Verify the voltage at the positap using a multimeter. Ensure the Connect Kit is as far away from nearby batteries/metals as possible as that can cause interference.

3) Try connecting from another phone/tablet to ensure it isn't an issue with your device. If you still have an error with another device, email into support@jb4connectkit.com and let us know you've performed all troubleshooting steps.


Try disconnecting then reconnecting the DB9 connector. If that doesn't work it's either an issue with the Connect Kit or a problem with the JB4 Master Chip. In order to test this you'll need access to another Connect Kit or BMS Data Cable. If you're unable to find either of these you're welcome to send your kit in for diagnostics. Email into support@jb4connectkit.com and let us know you're interested in having your kit tested and you've already performed the appropriate diagnostic steps.

You'll need to include a copy of your original purchase receipt for the Connect Kit.


There is an issue with your OBDII/CANbus wire installation. For further assistance, email support@burgertuning.com.

VW Passat/Jetta Owners - Set FUD to 1 as a test


If you are using a JB4 Connect Kit:
You have an incorrect setting toggled. Please look at the "OTG Data Cable Connection" field near the top of the Settings page (accessed by clicking the Settings Tab).

If you are using an OTG Cable:
1) Attach the OTG cable (*by itself) to your device then attach the BMS Data cable and try connecting again.

2) Download USB Device Info from the Play Store.
Open that app.
Connect the cable.
Does that app show anything connected?

If not, then there is an issue with your device, OTG cable, or BMS Data cable. If something does appear and you still have issues in JB4 Mobile, email into support@jb4connectkit.com and let us know you've performed the diagnostics for this specific error message.


1) Ensure the Connect Kit is as far away as possible from nearby batteries and metals. If using a metal JB4 enclosure do not mount/attach the Connect Kit to the enclosure as this can reduce bluetooth range.

2) Holding the phone next to the Connect Kit under the hood can help reduce issues due to signal strength.

3) Locking doors and waiting 5 min for ECU to reset, and restarting phone, can sometimes help.

4) Increasing Upload Timeout setting in the app to a higher number, or going up to 25, can be helpful. This setting is found directly above the 'Update' button in the Firmware Update page.

5) If all else fails and your Connect Kit has the separate blue power wire attached using a posi-tap connection to the JB4 harness, disconnecting the blue wire and *temporarily* attaching it to 12v on the vehicles battery rail will increase power to the Connect Kit and may allow the update to complete.


Make sure the device ACTUALLY supports Bluetooth 4.0 or higher. If it says it only supports calls and audio, odds are the unit is using a sub-par BT radio and simply will not work. Your only option is to use the BMS Data Cable and an appropriate OTG adapter.


If your 'Send' button is grayed out and you're unable to email logs, this means you don't have an email account setup with the DEFAULT Mail.app on your device. Note that the default Mail.app is NOT (I repeat NOT) the Gmail app, the Ymail app, or any other email app. It should be a blue icon with a white envelope.