What is a Smart Forfour EQ airbag control unit?
The Smart Forfour EQ airbag control unit is the central safety unit in your electric vehicle, instantly activating all occupant restraint systems, such as airbags and seatbelt pretensioners, in the event of an accident. It continuously monitors a multitude of sensors, stores relevant crash data, and thus ensures proper function for occupant protection.
This safety-relevant electronic control unit is installed in the Smart Forfour EQ model series 453, typically from model year 2014 to 2021.
Its main function is to receive signals from acceleration and impact sensors in order to precisely trigger the protection systems in the event of a collision.
Why is the Smart Forfour EQ airbag control unit defective?
The Smart Forfour EQ airbag control unit often becomes defective because it permanently stores crash data after an accident that must be deleted, or because internal hardware and software errors can occur that impair function and make a Smart Forfour EQ airbag control unit repair necessary.
Common causes are internal memory errors such as EEPROM problems or disturbances in the power supply of the control unit.
Communication errors in the CAN bus system or a failure of the internal logic can also cause the airbag control unit to break down.
These errors are often indicated by an illuminated airbag warning light in the cockpit, which requires immediate diagnosis and suggests a visit to a specialist workshop.
Common error codes for Smart Forfour EQ airbag control unit repair
During the Smart Forfour EQ airbag control unit repair, specific error codes occur that signal internal malfunctions, communication problems or memory errors of the control unit itself and enable a detailed diagnosis to identify the exact cause of the failure.
- B1000 → Control unit communication error → Internal defect or faulty connection to the airbag control unit
- B1151 → Internal memory error in the airbag control unit → Problem with the data memory (EEPROM) of the control unit
- B1210 → Voltage supply of the airbag control unit outside the specified range → Undervoltage or overvoltage at the control unit
- B1100 → Internal error in the airbag control unit (hardware error) → Hardware component of the control unit defective
- B1120 → Airbag control unit CAN communication error → Fault in the vehicle's data bus network
- B1234 → EEPROM read/write error in the airbag control unit → Inability to store or retrieve data correctly
- B1050 → Time/RTC error in the airbag control unit → Problem with the internal time function of the control unit
What part numbers are available for the Smart Forfour EQ airbag control unit repair?
For the Smart Forfour EQ airbag control unit repair, various OEM part numbers are relevant, which identify the exact model and manufacturer of the component and are essential for the correct selection of a replacement or repair part to ensure compatibility.
The Smart OEM part number A454 820 04 28 is often cited for the airbag control unit of the Smart Forfour and is verified by many repair services.
Another common Smart original part number is 4548200426, which is also confirmed by several spare parts dealers and car dismantlers.
The Bosch manufacturer number 0285001687 acts as an alternative or supplier number for the control unit with the Smart OEM number 4548200426, which identifies Bosch as an important supplier.
For newer Smart Forfour EQ models from 2020, the OEM number A4539013902 is typical for the airbag control unit, especially for the electric variant of this vehicle.
These precise part numbers are crucial if you need to have a Smart Forfour EQ airbag control unit repaired or replaced to safely resolve a failure.