B1150 airbag control unit fault

What does error code B1150 indicate in the airbag control unit?

Error code B1150 points to a severe hardware defect or a complete communication failure of the airbag control unit (SRS module). The unit can no longer perform its safety‑critical functions because internal electronic components—such as processors, memory chips (EEPROM), or circuit traces—are damaged.

Technically speaking, B1150 means that the control unit is either so severely damaged internally that it cannot boot up, or that the communication interface—such as the CAN‑bus transceiver—has failed. In both cases, the entire airbag system is disabled and offers no protection in the event of a crash.

This error code signals a critical condition requiring immediate diagnosis and repair by a specialist, as the vehicle’s passive safety is no longer guaranteed.

How do you recognize error B1150?

The primary symptom of error B1150 is the permanently illuminated or flashing airbag warning light (SRS symbol) on the instrument cluster. Additionally, diagnostic tools typically cannot establish communication with the airbag control unit, which significantly complicates further troubleshooting.

A key feature is the persistent activation of the SRS warning light. It does not turn off after starting the vehicle, indicating a permanent—not just intermittent—fault.

In the workshop, the problem often manifests as the airbag control unit failing to respond to diagnostic requests. Reading out the fault memory is therefore impossible because the communication layer is disrupted. The system is completely deactivated.

Attempts to clear the fault memory or reset the system by restarting the ignition usually prove unsuccessful, since the root cause is a physical defect.

What causes B1150?

The main cause of error code B1150 is an internal hardware defect within the airbag control unit. This includes faulty microchips, damaged circuit boards, or issues with the EEPROM memory. Other potential causes are overvoltage damage, moisture ingress leading to corrosion, or internal short circuits.

A direct hardware failure on the circuit board is the most common cause. Components such as processors, capacitors, or the memory chip itself may fail due to aging, thermal stress, or manufacturing defects.

An EEPROM error (non-volatile memory) can also trigger B1150. This issue is closely related to codes like B1120 but may also be classified under B1150 as a general hardware fault.

Overvoltage damage—caused, for example, by an incorrectly connected battery or jump-starting—can destroy sensitive electronic components inside the control unit and result in this error.

Rarer but possible are water or moisture damages that lead to corrosion on the circuit board and short circuits. Faulty connectors or broken cables can also disrupt communication and indirectly cause the error.

Which vehicles are affected by B1150?

Error code B1150 occurs across multiple brands and numerous models. Vehicles from Mercedes-Benz, BMW, Opel, Skoda, Renault, as well as various American and Japanese manufacturers, are among those affected. Repair is possible for a wide range of control units.

At Airbag24, we repair control units displaying error B1150 for a broad spectrum of vehicles. These include:

Mercedes-Benz: C-Class Coupe (C205), model years 2015–2023

BMW: 5 Series Touring (F11, F11 LCI), model years 2010–2017

Opel: Mokka A (2012–2019)

Renault: Zoe II (2019–2024)

Skoda: Citigo (2011–2020), Kodiaq RS (Mk2), Roomster Scout (Mk1)

Other brands: Bentley (Continental SC, Bentayga Hybrid), Chevrolet (Corvette C4), Dacia (Sandero II, Duster I), Daihatsu (Copen L880), Dodge (Charger LX), Infiniti (Q50S), Jeep (Grand Cherokee WJ, Compass MP), Rover (Range Rover Classic), Smart (Fortwo, Forfour), Subaru (Crosstrek, Leone AL), Suzuki (Spacia MK53S), and Toyota (4Runner SR5).

How is error B1150 professionally repaired?

Professional repair of error B1150 involves electronic refurbishment of the removed airbag control unit. Defective components on the circuit board—such as memory chips (EEPROM) or processors—are replaced, and the software is restored to factory settings, thereby fully reinstating functionality.

After submission to Airbag24, the control unit undergoes a comprehensive technical analysis. Our technicians inspect the circuit board for visible damage, measure electronic components, and analyze the software to pinpoint the exact source of the fault.

The actual repair is performed at the component level. Defective parts such as chips, capacitors, or transceivers are professionally replaced. Cold solder joints or damaged traces are re-soldered. Subsequently, any existing crash data is erased, and the unit is fully reset.

Following successful repair, each control unit undergoes a final test on a specialized test bench to verify proper functionality and communication. This refurbishment is a cost-effective and sustainable alternative to expensive new purchases and does not require subsequent coding in the vehicle. We provide 2 years' statutory liability for defects on all repairs.