Airbag control unit with part number 55705

What is the function of Airbag Control Unit 55705?

The airbag control unit with part number 55705 is the central control module for the occupant protection system (Supplemental Restraint System, SRS). Its primary task is to process sensor data in order to deploy airbags and seatbelt pretensioners precisely and at the right moment in the event of a crash.

This control unit is specifically designed for use in the Alfa Romeo GTV 916. It continuously monitors all connected components of the airbag system, including crash sensors, seat occupancy mats, seatbelt pretensioners, and the airbag modules themselves, ensuring constant operational readiness.

In the event of a collision, the electronics determine within milliseconds which restraint systems need to be activated to provide optimal protection for occupants. After deployment, the unit stores the crash data and self‑locks for safety reasons, necessitating professional repair.

Why does Airbag Control Unit 55705 fail?

The most common cause of failure for control unit 55705 is the storage of crash data after an airbag deployment, which causes the unit to deactivate itself. Other causes include internal malfunctions that result in persistent SRS error messages and a lit airbag warning light.

Following a crash in which the airbags or seatbelt pretensioners have deployed, the control unit writes so‑called “crash data” into its internal memory. This procedure is a safety measure intended to prevent reuse without inspection and repair. The system then reports an internal, non‑erasable fault.

However, it’s important to note that the root cause of the fault isn’t always the control unit itself. Defective external components—such as damaged sensors, faulty wiring, corroded connectors, or a malfunctioning seat occupancy mat—can also trigger error messages. Therefore, a thorough diagnosis is essential before removal.

How can you recognize a defect in Control Unit 55705?

A defect in Airbag Control Unit 55705 typically manifests as a permanently illuminated or flashing airbag warning light on the instrument cluster. Often, SRS error messages (Supplemental Restraint System) are also displayed, and the fault memory cannot be cleared using a diagnostic tool.

The primary and unmistakable sign is the activated airbag warning lamp. After starting the vehicle, this light not only briefly illuminates but remains on continuously, indicating a serious issue with the restraint system.

Another clear symptom occurs when a workshop attempts to read the fault memory and finds entries such as “internal fault” or “crash data stored.” These error codes are permanent and cannot be erased via standard On‑Board Diagnostics (OBD).

In which vehicles is Control Unit 55705 installed?

The airbag control unit with part number 55705 is specifically designed for the Alfa Romeo GTV of the 916 series. At Airbag24, this control unit is professionally refurbished for the relevant model years and facelift versions of this sporty coupe and spider.

At Airbag24, repair services for Control Unit 55705 are offered for the following specific models:

Alfa Romeo: GTV 916 (model years 1995–2003) as well as the GTV 916 Facelift (model years 2003–2005).

Is repairing Control Unit 55705 worthwhile?

Repairing Airbag Control Unit 55705 offers significant financial benefits. Instead of spending up to €750 on a new unit, targeted refurbishment can save up to 90% of the cost. Additionally, no time‑consuming re‑coding is necessary.

The biggest advantage lies in substantial cost savings. In most cases, after a crash, only the software needs to be reset and the crash data erased—rather than replacing expensive hardware—making repair an extremely economical solution.

A repaired control unit becomes fully functional again immediately upon reinstallation (plug-and-play). Since the original configuration is preserved, reprogramming is not required. Two years' statutory liability for defects is provided for the completed repair.

How does the repair process work at Airbag24?

The repair of Control Unit 55705 at Airbag24 follows a standardized procedure: After careful removal and shipment, the unit is analyzed, its software is restored to factory settings, and all stored crash data is completely erased. A final quality check ensures proper functionality.

First, the control unit must be removed from the vehicle while observing critical safety precautions. This includes disconnecting the battery (first the negative terminal, then the positive) and allowing at least 10 minutes for the system to discharge completely. Electrostatic discharges must also be avoided.

After sending the unit to Airbag24, our technicians perform a software reset. This process restores the original factory settings and clears the blockage caused by the stored crash data.

Following successful erasure and a thorough quality check, the control unit is returned. After reinstallation, only a single clearing of the system’s fault memory is required. The repair comes with 2 years' statutory liability for defects.