B1684 - Configuration fault or internal control unit fault airbag control unit fault

What does error code B1684 mean in the airbag control unit?

On Kia vehicles, error code B1684 reports that the configuration of the airbag control unit does not match the vehicle configuration, or that there is a fault in the internal data of the control unit. The control unit itself stores this fault in the fault memory and switches on the airbag warning light, which shows the fault to the driver.

The code relates to the configuration and internal data of the control unit itself.

In an emergency, the control unit triggers the airbags and seatbelt pretensioners, and it is this very control unit that is affected by error code B1684.

How do you recognise error code B1684?

You recognise error code B1684 by the airbag warning light staying on permanently and the code being stored in the fault memory of the airbag control unit. The entry cannot be permanently deleted, and it is read out with a suitable diagnostic tool connected to the vehicle.

If you see the airbag warning light burning permanently, this is the visible sign that a fault is stored in the control unit. Only the readout with a diagnostic tool shows whether error code B1684 is behind it. The warning light alone says nothing about the cause.

What causes error code B1684?

Error code B1684 has its cause in the airbag control unit itself, because either the configuration there differs from the vehicle or an internal fault is present. The possible triggers within the unit are ageing, soldered joints, moisture or voltage spikes, and, after an accident, stored crash data.

• Crash data from an accident stored in the control unit
• Ageing electronic components in the control unit
• Soldered joints, moisture or corrosion in the control unit
• Voltage spikes caused by a weak battery or by jump-starting

Which of these causes applies to your vehicle is only shown by examining the control unit. Until then, the cause cannot be derived from the error code alone.

In which vehicles does error code B1684 occur?

Error code B1684 is known on Kia vehicles, for example the Carnival, EV2, EV3, EV9, Proceed and XCeed models. The meaning may also differ on other vehicles, and the list is not complete, because not every model has been recorded.

Whether the code is present on your vehicle is only shown by the fault memory once it has been read out. The model name alone does not allow any reliable conclusion about this.

How is error code B1684 resolved?

If the cause lies in the control unit itself, error code B1684 is resolved by removing the unit and repairing it at Airbag24 in Berlin. Beforehand, you have the fault memory read out with a diagnostic tool, and the battery is disconnected before the control unit is removed.

To do this, you create a repair order online and send the removed control unit to Airbag24. Inspection, repair and testing usually take 3–4 working days.

The repaired control unit comes back with all vehicle data and is ready for use as soon as it is refitted — no coding or programming is required.

Work on the airbag system should be left to qualified specialists. This also applies to removing the control unit, for which the battery must be disconnected beforehand.