B1105 airbag control unit fault

What does error code B1105 mean in the airbag control unit?

Error code B1105 indicates a specific internal fault within the airbag control unit. Depending on the vehicle manufacturer, this code may point to a software malfunction, a failure in the discharge lamp circuit, or a defective airbag deactivation switch. In response, the control unit locks down safety‑critical functions and prevents the erasure of crash data.

Technically speaking, B1105 is a manufacturer‑specific code whose exact meaning can vary. For example, on a Peugeot 208 I, it usually signifies an internal software error that requires reprogramming or repair of the control unit.

In Citroën vehicles, however, B1105 often points to a malfunction of the discharge bulb or its associated ballast, including potential connection issues. Meanwhile, on a Maserati Coupe M138, the code is typically triggered by a defect in the passenger‑side airbag deactivation switch.

Regardless of the precise cause, this fault condition causes the airbag warning light to illuminate and forces the entire system into a passive mode for safety reasons. Simply clearing the fault memory is usually not sufficient, as the underlying defect persists.

What symptoms indicate error B1105?

The primary and most obvious symptom of error B1105 is the SRS/Airbag warning light permanently illuminated in the instrument cluster. This light does not extinguish even after the engine starts. Consequently, airbag functions are disabled, significantly compromising occupant safety in the event of a crash.

Another clear sign is that the error code cannot be permanently cleared. Workshops often observe that the code reappears immediately or shortly thereafter in the fault memory, confirming that this is a persistent internal fault rather than a sporadic issue.

In some cases, following a collision, stored crash data may also fail to reset due to error B1105. The control unit remains locked until the root cause is resolved.

What are the most common causes of error code B1105?

The causes of B1105 lie directly within the airbag control unit and can be grouped into three main categories: internal software errors, defects in specific hardware components such as switches or lamp circuits, and retained crash data. External factors like moisture or contact damage can further exacerbate the problem.

An internal software error is one of the primary causes, where the control unit’s operating software becomes corrupted, preventing proper processing of sensor signals and control of airbag components.

A hardware defect in the discharge lamp or the passenger‑side airbag deactivation switch represents another specific cause. Here, the fault resides either in the electronic circuitry or in the mechanical component itself.

Similar to error code B1111, which also indicates an internal fault, code B1105 reappears after being cleared unless the physical or software-related root cause inside the control unit has been fixed. Before working on the system, always disconnect the battery for at least 10 minutes as a safety precaution.

Which vehicles are affected by error B1105?

Error code B1105 occurs across manufacturers, particularly among European and Asian brands. Affected models include various versions from Peugeot, Citroën, Maserati, Nissan, and Hyundai. This specific internal fault is also diagnosed in vehicles from Dodge, Chrysler, Smart, Porsche, and other manufacturers.

At Airbag24, we repair error code B1105 for a wide range of models, including:

Citroën: C‑Zero I (2009–2020) Chrysler: Town & Country AS Dodge: Ram 2nd Gen, Stealth Z16A, Viper ACR VX II Hyundai: Azera IG Infiniti: Hybrid M35h Iveco: Urbanway 12M Maserati: Coupe M138 (2001–2004) and M138 Facelift (2004–2007) Nissan: Altima L34 (2018–2022) and L34 Facelift (2022–), Maxima A32 (1995–2000), Murano Z50 (2002–2008) Peugeot: 208 I (2012–2015) and I Facelift (2015–2019) Porsche: Panamera Diesel 970 Rolls‑Royce: Silver Spur Series IV Rover: Range Rover Holland & Holland Smart: Fortwo Crosstown, Forfour Greystyle Subaru: Pleo L285 Toyota: Vellfire Executive Lounge

How is error code B1105 professionally repaired?

Professional repair of error B1105 at Airbag24 focuses on eliminating the actual root cause within the control unit. Following a thorough analysis, defective components are replaced, software errors are corrected, or stored crash data is completely erased, restoring full functionality to the airbag system.

The process begins with removing the airbag control unit from the vehicle. The unit is then sent in for repair. At Airbag24, the control unit first undergoes a thorough diagnosis to identify the exact source of the fault—whether it’s software, the lamp circuit, or a switch.

Depending on the findings, defective electronic components on the circuit board are replaced, or the software is reprogrammed. Any crash data present is also completely erased. Following successful refurbishment, the unit undergoes an extensive functional test to ensure proper operation.

This approach not only provides a long-lasting solution but also ensures that the original control unit, coded specifically for your vehicle, remains intact. A 2-year warranty is provided on the completed repair.

Is Repair Worth It for Error B1105?

Repairing the airbag control unit when error B1105 occurs is an economically and technically sensible alternative to purchasing a new part. The cost of a new control unit can reach up to 400 euros, whereas a repair typically ranges from 99 to 150 euros, making it significantly more affordable.

A key advantage of repair is that the original control unit is preserved. This eliminates the time-consuming and costly programming or coding procedures often required when installing a new unit. The repaired device can be reinstalled using a simple plug-and-play method.

Moreover, professional repair offers a sustainable and reliable solution. By precisely addressing the root cause, full functionality of the airbag system is restored and backed by an extended warranty, helping to maintain both vehicle safety and value.