B15381B - Interruption in the deployment chain airbag control unit fault

What does error code B15381B mean in the airbag control unit?

Error code B15381B reports an interruption in the firing circuit of the restraint system, that is, an open firing circuit or excessive resistance within it. The firing circuit, through which the airbags are triggered, is therefore affected, and the airbag control unit stores the fault and switches on the airbag warning light.

The firing circuit is part of the restraint system and is monitored by the control unit. An interruption or excessive resistance is therefore stored as a fault, and the airbag warning light shows this condition to the driver.

How do you recognise error code B15381B?

You recognise error code B15381B by the airbag warning light staying on permanently, the code being stored in the fault memory of the airbag control unit, and this entry not being permanently erasable. The code is read out with a diagnostic tool that makes the fault memory visible, so that the cause can be narrowed down.

The warning light alone does not show which fault is present. Only the read-out code identifies the interruption in the firing circuit, and every further check is guided by it.

What causes error code B15381B?

Possible causes of error code B15381B are interruptions or increased resistance in the firing circuit of the restraint system. Connectors, lines, the airbag module or a sensor in the circuit, and the airbag control unit itself, can be responsible, and only the check shows which of these is affected.

• A connector in the firing circuit may be loose, damaged or corroded.
• A line of the firing circuit is interrupted or damaged by chafing.
• The airbag module or a sensor in the firing circuit may be defective.
• The airbag control unit itself may be defective, for example due to ageing electronic components or soldered joints.

Whether one of these causes applies is clarified by checking the individual parts at a specialist workshop.

In which vehicles does error code B15381B occur?

Error code B15381B occurs in Polestar vehicles, specifically in the Polestar 1, Polestar 2, Polestar 3, Polestar 4 and Polestar 5 models of the first model line. For these models, the code is therefore known in connection with the firing circuit.

Outside these vehicles the meaning may differ, and the list is not complete.

How is error code B15381B resolved?

Error code B15381B is resolved by first having the fault memory read out with a diagnostic tool and then narrowing down the cause. If the cause lies in a connector, a line, the airbag module or a sensor, have these parts checked first at a specialist workshop; if it lies in the control unit, the send-in process applies.

At the specialist workshop, the connections of the firing circuit, that is, the connectors and lines, are checked before the control unit comes into consideration. Work on the airbag system belongs in qualified hands.

If the cause lies in the control unit itself, first disconnect the battery and then remove the control unit. Create a repair order online and send the device to us. Checking, repairing 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.