Alpine A390 I airbag control unit repair

What is an Alpine A390 I airbag control unit?

The Alpine A390 I airbag control unit is the central control unit of the restraint system (SRS). It evaluates the signals from the crash sensors and, in an accident, decides within milliseconds which airbags and seatbelt pretensioners deploy.

The control unit continuously monitors the entire system and reports every fault it detects via the airbag warning light.

The control unit is fitted in the Alpine A390 I (since 2025). After an accident it stores crash data and locks itself. The warning light then no longer goes out on its own.

Seatbelt pretensioners and airbags are triggered by the control unit. To do this, it continuously compares the sensor readings and at the same time checks its own functions, so that everything works reliably in an emergency.

Why is the Alpine A390 I airbag control unit defective?

The most common cause of a defective Alpine A390 I airbag control unit is crash data stored after an accident, even if no airbag deployed. Other causes are aged electronic components, cold solder joints, moisture and corrosion on connectors, and voltage spikes.

Ordinary diagnostic tools cannot delete stored crash data. The fault therefore remains, even if the battery has been disconnected or the fault memory has been cleared several times.

Typical signs are a permanently lit airbag warning light, a fault memory that cannot be cleared, or a diagnostic tool that cannot connect to the control unit.

If the warning light is on, the protective function of the system is no longer reliably available. You should therefore have the cause clarified promptly and not simply carry on driving as if nothing had happened.

Common error codes for Alpine A390 I airbag control unit repair

The error codes for the Alpine A390 I airbag control unit show what kind of fault the restraint system has detected. Here, this mainly concerns communication between the control unit and the rest of the vehicle.

The following code is known for this control unit:

• U0151 → Communication with the airbag control unit lost

Error codes are read out with a diagnostic tool. A code alone does not reliably show that the control unit is defective. Connectors, wiring or an airbag module can also be the cause. Only an inspection will clarify it.

The codes are indications of the area in which the system has detected a deviation. They do not yet say which component is affected in detail, and therefore do not replace the inspection of the unit.

What part numbers are available for the Alpine A390 I airbag control unit repair?

The part number is on the label of the Alpine A390 I airbag control unit and determines the exact version. Within a model series there are different numbers depending on equipment and year of manufacture.

We have not yet recorded a part number for this vehicle. Please read the number from the label of your unit and enter it in the repair order.

On the label you will usually find several numbers and details. Make sure to note the part number of the control unit itself, and ideally photograph the label as well.

Proceed as follows: have the fault memory read out, disconnect the battery and remove the control unit. Then create a repair order online and send in the unit. Processing at Airbag24, including inspection, repair and testing, usually takes 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.