B100355 airbag control unit fault

What does error code B100355 mean in the airbag control unit?

Error code B100355 indicates an internal coding error in the airbag control unit, specifically related to the ABS system. The message “ABS Present Error Coding code error” suggests that the ECU’s software configuration is inconsistent or that communication with the ABS module via the CAN bus is disrupted. This error is often triggered by stored crash data or internal software issues.

Technically, this means that the airbag control unit (ECU) has registered incorrect or missing configuration information regarding the presence and status of the anti-lock braking system (ABS). Such coding is crucial for the proper functioning of the entire restraint system (SRS), as the airbags’ deployment logic also relies on wheel speed sensor data from the ABS system.

In many cases, the root cause is not a complete hardware failure but rather a processor blockage caused by crash data stored after an accident or an internal software glitch. As a result, the ECU enters a safety mode, deactivates the airbag system, and logs error B100355.

How can you recognize error B100355?

The primary symptom of error B100355 is a continuously illuminated or flashing airbag warning light on the instrument cluster. Additionally, diagnostic tools may fail to establish communication with the airbag control unit, or only detect faulty communication, complicating troubleshooting. In this state, the airbag system is completely disabled.

The airbag warning light (SRS light) is the most obvious indicator. It does not extinguish upon vehicle startup as usual but remains permanently lit to alert the driver to a critical system fault.

Another common sign is that workshop diagnostic equipment, such as a HiScan scanner, cannot connect to the airbag control unit. The module fails to respond to requests because it is in safety mode due to the internal error.

As a direct consequence of this error, the entire passive safety system—including all airbags and seatbelt pretensioners—becomes inoperative. This poses a significant safety risk in the event of a collision.

What are the most common causes of error B100355?

The main causes of error code B100355 are internal software faults or incorrect coding related to the ABS system. A very frequent cause is crash data stored after an accident, which locks the ECU. Faulty communication links, such as those on the CAN bus, can also trigger this error.

Internal software and coding errors are the most common cause. These involve inconsistencies in the ECU’s internal data that prevent successful system diagnostics.

Stored crash data following an accident is another major trigger. Even after bodywork repairs, these data remain in the ECU’s memory, blocking normal operation until they are professionally cleared.

Disruptions in CAN-bus communication between the airbag and ABS control units can also lead to this error. Before sending the ECU for repair, external factors such as crushed cables under the seats, corroded connectors, or defective seatbelt buckles and seat occupancy mats should be ruled out.

On which vehicles does error code B100355 occur?

Error code B100355 is specific to the airbag control unit with part number B100355, installed in the Hyundai Ioniq 5 of the NE series. At Airbag24, we specialize in repairing precisely these ECUs for the affected model years.

At Airbag24, we repair error code B100355 for the following model:

Hyundai: Ioniq 5 NE (model years 2021–2024)

How is error B100355 repaired?

Professional repair is a purely electronic process. After removing and shipping the ECU to Airbag24, a detailed analysis is performed. Crash data is erased, internal coding is corrected, and, if necessary, defective components such as processors or internal circuitry are replaced. Final tests ensure full functionality.

Upon receipt of the removed ECU at Airbag24, a comprehensive board-level inspection takes place. Our technicians read the internal fault memory to pinpoint the exact cause of the coding error.

The core of the repair involves erasing any existing crash data and correcting the faulty coding. The ECU is recalibrated to restore proper communication with the ABS system and other vehicle components.

If physical damage to electronic components such as processors or capacitors is detected during the analysis, these parts will be professionally replaced. Upon completion of the repair, the control unit undergoes a functional test on a test bench that simulates real-world vehicle conditions.

The advantage of repair is that, once reinstalled, the device is immediately ready for operation and no additional programming in the vehicle is required. We provide 2 years' statutory liability for defects on all repairs.