What is a Seat Leon ST Mk3 airbag control unit?
The Seat Leon ST Mk3 airbag control unit is the central safety unit in your vehicle, precisely activating all occupant restraint systems, such as airbags and seatbelt pretensioners, in the event of an accident. It continuously monitors sensors, stores relevant crash data, and is essential for the correct functioning of all safety systems.
This safety-relevant module not only controls the deployment of the airbags, but also the permanent monitoring of the entire restraint system.
It has been specially developed for the Seat Leon III Mk3, Type 5F, and ensures maximum occupant safety in the event of an impact.
Why is the Seat Leon ST Mk3 airbag control unit defective?
A Seat Leon ST Mk3 airbag control unit often fails because it stores crash data after an accident, requiring replacement or professional repair, or because internal memory and software errors occur. Communication problems with other vehicle modules can also cause failure.
After an airbag is deployed, the control unit stores indelible crash data, which means that the airbag warning light remains permanently activated.
Internal hardware or software defects, such as a faulty EEPROM memory or a failure of the internal processor, can also lead to the failure of the control unit.
An interruption in the power supply or corrosion on the connectors can also trigger communication errors that cause the control unit to report it as broken or faulty.
Common error codes for Seat Leon ST Mk3 airbag control unit repair
When diagnosing a faulty Seat Leon ST Mk3 airbag control unit, specific error codes will occur that indicate internal defects or communication problems within the module. Reading these codes is essential for a targeted Seat Leon ST Mk3 airbag control unit repair and helps identify the exact cause.
- B2000 → Control unit defective → This is a typical internal error of the airbag control unit, which often requires repair or replacement of the module.
- B1000 → Control unit communication error → A faulty or missing data connection between the airbag control unit and the vehicle network leads to this failure.
- B1023 → Airbag control unit voltage error → Problems with the internal voltage supply of the control unit, often a 5V supply, trigger this error.
- B1090 → Memory error / EEPROM error in the control unit → A defect in the internal data memory of the airbag module, such as the EEPROM, causes this fault.
- B1760 → Internal memory error in the airbag control unit → This code indicates general problems with the internal memory of the control unit.
- B1810 → Internal process error / software error in the control unit → A malfunction in the software or internal processing of the control unit is displayed here.
- B1920 → Communication error between airbag ECU and other control units → This error indicates problems in communication with external vehicle control units.
- B2100 → Internal hardware error in the control unit → A defect in the electronic components inside the airbag control unit leads to this error.
What part numbers are available for the Seat Leon ST Mk3 airbag control unit repair?
For the Seat Leon ST Mk3 airbag control unit repair, the OEM part numbers 3Q0 959 655 AC and 3Q0 959 655 AD are primarily relevant. These come directly from Seat/VAG and ensure exact compatibility, which is crucial for the system's safety.
The main number for the Seat Leon 5F Mk3 airbag control unit is 3Q0 959 655 AC , which is considered an exact OEM part number and is often referenced by professional repair services.
An alternative and also original replacement number is 3Q0 959 655 AD , which can be found in VAG parts catalogs as a compatible variant for the Seat Leon ST Mk3 airbag control unit repair.
In addition, there are Bosch supplier numbers (e.g., starting with 5F0 959 655) that represent a reference to the original part 3Q0 959 655 AC; these should be checked directly in the Bosch original parts catalog if necessary.
It is of utmost importance to always check the exact OEM number of the original component when replacing or repairing it, as the airbag system is safety-critical and only the correct component will function properly.