B1990 airbag control unit fault

What does error code B1990 indicate in the airbag control unit?

Error code B1990 indicates that crash data has been permanently stored in the airbag control unit. Following a collision or an accident-like event, the control unit internally locks itself to prevent the airbags from deploying again. This condition is not a hardware defect but rather a safety-related software lock that must be manually reset.

Technically speaking, this means that after registering an impact, the control unit enters a locked state. In this mode, it ceases normal operation and no longer communicates properly with the rest of the vehicle’s systems. This is a manufacturer‑specified safety measure.

The crash data is stored in a non-volatile memory area of the control unit. As long as this data remains, the airbag system stays deactivated, and the corresponding warning light on the instrument cluster stays illuminated. The fault cannot be cleared using conventional diagnostic tools.

How can you recognize error code B1990?

The primary and most obvious symptom of error code B1990 is the continuously illuminated airbag warning light (SRS lamp) on the instrument cluster. The system reports a malfunction and is no longer operational. When reading the fault memory with a diagnostic tool, code B1990 appears as “crash data stored” or with a similar description.

The airbag warning light does not turn off after starting the vehicle, as it would in a functioning system. This clearly signals to the driver that the passive safety systems are unavailable.

In the event of another accident, the airbags and seatbelt pretensioners would fail to deploy, posing a significant safety risk. In some vehicles, additional messages may appear on the driver information display indicating a fault in the airbag system.

What causes error code B1990?

The sole cause of error code B1990 is the storage of crash data in the airbag control unit after detecting an accident. Even minor collisions where not all airbags deploy can trigger this entry and subsequent locking of the control unit. This is an intended function, not a malfunction.

Such an entry is generated when the vehicle’s built-in acceleration sensors detect values exceeding a predefined threshold. This can occur during a minor rear-end collision where only the seatbelt pretensioners activate, as well as during severe collisions involving airbag deployment.

An important note from workshop experience: Before the crash data can be erased from the control unit, all damage caused by the accident—especially to components of the airbag system such as sensors or pretensioners—must be professionally repaired. Otherwise, the fault cannot be permanently cleared or will reappear immediately.

Which models exhibit error code B1990?

Error code B1990 specifically occurs in certain vehicle models where the airbag control unit becomes locked following an accident. Affected models include the Maserati Ghibli SS and the Toyota Harrier XU60 series, including its facelifted versions. At Airbag24, this error code is professionally repaired for these vehicles.

Airbag24 offers repair services for the airbag control unit with error B1990 for the following vehicles:

Maserati Ghibli SS

Toyota Harrier XU60 (model years 2013–2017) and XU60 facelift (model years 2017–2020)

How is error B1990 repaired?

Professional repair of error B1990 focuses on erasing the stored crash data and resetting the control unit. After sending the module to Airbag24, it is read out, the crash data is removed using specialized equipment, and the device is reinitialized. Finally, functionality is verified to restore full operability.

At Airbag24, repairs follow a standardized process. After removal and shipment, the control unit is first scanned with professional diagnostic tools to confirm error B1990. Subsequently, the crash data stored in internal memory is selectively deleted.

Following data deletion, the control unit undergoes a reset and reinitialization. If necessary, electronic components on the circuit board are also inspected to ensure no secondary damage resulted from the accident. A final verification in the test system ensures that the module once again communicates flawlessly and monitors all functions correctly.

The repaired control unit can typically be reinstalled in the vehicle without additional coding after return shipping (plug-and-play). We provide a 12-month warranty on the repair performed.