B00A087 - WSS malfunction (seat occupancy mat defective) airbag control unit fault

What does error code B00A087 mean?

Error code B00A087 indicates a communication fault in the airbag system, specifically occurring in Mercedes-Benz vehicles. Technically, it signifies an incorrect or missing message in the data exchange of the airbag control unit, pointing to issues with information transmission between the control unit and other system components.

In detail, this code refers to a non-specific communication malfunction. The control unit either receives implausible data from sensors or fails to receive expected signals from other control units. As a result, the system can no longer ensure that all components function correctly.

The term "WSS" in the error message often suggests involvement of the Weight Sensing System (seat occupancy detection), whose communication may be disrupted. As long as this error remains active, the airbag control unit cannot reliably guarantee its protective functions.

How do you recognize error B00A087?

The primary symptom of error B00A087 is the persistent illumination of the airbag warning light on the instrument cluster. Additionally, diagnostic tools may fail to establish communication with the airbag control unit, or communication may be severely impaired. In some cases, additional error messages appear simultaneously in other vehicle systems.

The airbag warning light does not extinguish after starting the vehicle. This is a clear indication that the safety system is disabled and would either fail to deploy or deploy incorrectly in the event of a crash.

Often, this error is only detected during routine vehicle diagnostics when the fault memory is read out. Apart from the warning light, the vehicle itself typically shows no other driving‑related malfunctions.

What causes error code B00A087?

The causes of B00A087 are varied, ranging from simple contact problems to internal defects. Common triggers include poor electrical connections or a defective coil spring. Water damage, overvoltage, or stored crash data following an accident or severe impact can also block the control unit.

A frequent mechanical source of failure is the connectors beneath the seats, which become damaged due to frequent seat adjustments. Similarly, the coil spring on the steering wheel undergoes constant wear from steering movements and can disrupt signal transmission.

Another critical issue lies in internal damage within the control unit itself. Intruding water can cause short circuits on the circuit board, while overvoltage can harm the sensitive electronics.

After a crash, the control unit stores so‑called crash data. These cannot be erased using standard diagnostic equipment and can disable the device’s functionality. Interestingly, even a door slam perceived as too forceful by the system can trigger such a lockout.

Error B00A087 may also occur in conjunction with other error codes. Codes like B1000 (internal control unit defect), B1010, or 65535 (power supply issues), as well as sensor errors (0214, FFFF, 0666, 0667, 04C1) may point to deeper systemic problems.

In which vehicles does error B00A087 occur?

Error code B00A087 has been documented primarily in certain models of the Mercedes-Benz brand. Newer SUV and pickup series are particularly affected. Repairing this specific communication fault requires expertise in the electronics of these vehicles.

At Airbag24, we repair error code B00A087 for the following Mercedes-Benz models:

Mercedes-Benz GLA-Class X156 SUV (model years 2013–2020)

Mercedes-Benz GLS-Class X167 SUV (model years 2019 to present)

Mercedes-Benz X-Class X470 Pickup (model years 2017–2020)

How does repair work at Airbag24?

Professional repair of error B00A087 focuses on analyzing and restoring the removed airbag control unit. At Airbag24, the unit is thoroughly inspected, stored crash data is erased using specialized software, and the device is reset to factory settings. A functional test follows, and you receive 2 years' statutory liability for defects on the repair.

Before removing the control unit, a qualified workshop should perform a diagnosis. This includes visual inspection of all airbag system components and reading out the fault memory to identify any accompanying errors.

Important safety note: Work on the airbag system must be carried out exclusively by trained specialists in compliance with all legal and manufacturer‑specific regulations.

Following submission to Airbag24, electronic repair takes place. If crash data is the root cause, it will be deleted and the unit fully reset. Unlike replacing the part with a new one, our repairs generally do not require re‑coding or reprogramming of the vehicle.

Finally, the control unit is tested to ensure proper functionality. This professional repair is a reliable and cost-effective alternative to the expensive purchase of a new control unit.