Audi A4 B8 airbag control unit repair

What is an Audi A4 B8 airbag control unit?

The Audi A4 B8 airbag control unit is the central safety unit in the vehicle, activating all occupant restraint systems in the event of an accident. It receives signals from numerous sensors, makes split-second decisions about airbag and seatbelt pretensioner deployment, and stores important crash data for post-accident diagnostics.

This essential module is responsible for the correct functioning of the entire passive safety system. It continuously communicates with other control units in the vehicle via the CAN bus.

Regular diagnosis and, if necessary, an Audi A4 B8 airbag control unit repair are crucial for vehicle occupant safety.

Why is the Audi A4 B8 airbag control unit defective?

An Audi A4 B8 airbag control unit often malfunctions because it develops internal software errors, communication problems with other vehicle systems occur, or crash data is permanently stored in memory after an accident. These malfunctions cause the airbag warning light in the instrument cluster to illuminate continuously, rendering the system inoperable.

Typical causes of failure include low voltage, internal processor errors or an incorrect vehicle identification number (VIN).

Damage caused by moisture can also lead to a defect, which makes an Audi A4 B8 airbag control unit repair necessary instead of an expensive replacement.

Common error codes for Audi A4 B8 airbag control unit repair

During an Audi A4 B8 airbag control unit repair, specific error codes are often read out, indicating a malfunction within the control unit itself. These codes typically involve problems with the power supply, internal communication, or a complete inaccessibility of the module, making a diagnosis essential.

• U101100 → Undervoltage detected → Airbag control unit
• B200049 → Airbag control unit error → Airbag control unit
• U015100 → No communication → Airbag control unit
• 01321 → Airbag control unit not accessible → Airbag control unit
• 00003 → Control unit defective → Airbag control unit
• 00474 → Immobilizer control unit (speedometer may be affected) → Airbag control unit
• 01794 → Control unit incorrect chassis number → Airbag control unit

These error codes relate exclusively to the airbag control unit and require specific repair in the workshop.

What part numbers are available for the Audi A4 B8 airbag control unit repair?

For Audi A4 B8 airbag control unit repairs, there are several original Audi and compatible Bosch OEM part numbers, all relevant to the A4 B8, A4 Avant B8, and A4 Allroad B8 models. Correct identification of the part number is crucial to ensure the compatibility of the repaired or replaced control unit and prevent failure.

These numbers ensure that the airbag control unit fits the vehicle perfectly and optimally fulfills its safety function.

Verification using the chassis number is always recommended for a safe Audi A4 B8 airbag control unit repair.

This list contains all verified OEM part numbers for the Audi A4 B8 airbag control unit, important for any repair.

The Bosch part number 5WK44111 is often used as a reference for compatible Audi airbag control units.