Airbag control unit with part number A2C15939904

What is the function of the airbag control unit A2C15939904?

The airbag control unit with part number A2C15939904 is the central control module for the occupant safety system (SRS) in the Peugeot Partner III. It continuously monitors all connected sensors and components, evaluates data from crash sensors in the event of an accident, and deploys the airbags and seatbelt pretensioners as needed. Additionally, it stores relevant crash data.

Technically speaking, this module serves as the brain of the entire restraint system. It ensures that all components—from impact sensors to individual airbag modules—are operational. Each system start-up is accompanied by a self-test, the result of which is indicated by the airbag warning light on the instrument panel.

A critical function is the storage of crash data after a collision. This data deliberately locks the control unit, requiring a full system check. The unit is known under the main part number A2C15939904, but it may also be installed in vehicles using the alternative part numbers 9653190880, 9803916880, and 9823741280.

Why does the control unit A2C15939904 fail?

The most common cause of failure for A2C15939904 is the retention of crash data following an accident, which locks the unit. Other defects are often found at the hardware level, such as damage caused by overvoltage or moisture, as well as failures of internal electronic components like microcontrollers or capacitors on the circuit board.

After an accident in which the airbags have deployed, the control unit writes an irreversible fault entry into its internal memory. This “crash lock” is a safety feature that prevents further operation until professional repair or a reset has been performed. At that point, the system is disabled, and the airbag warning light remains illuminated.

Electronic faults are also a frequent cause. Overvoltage—such as from a jump-start—can damage sensitive components. Moisture inside the vehicle can lead to corrosion on the circuit board and cause short circuits. Faulty connectors or wiring within the vehicle can likewise result in malfunctions that are mistakenly attributed to the control unit, even though the actual defect lies externally.

Over time, individual components like capacitors or the microcontroller itself may also fail. These issues often manifest as internal errors that cannot be cleared with standard diagnostic tools, necessitating component-level repairs.

How do you recognize a defect in A2C15939904?

The clearest symptom is a permanently lit or flashing airbag warning light on the dashboard. Communication with the diagnostic tool is frequently lost, often leaving error code B1000 stored in the fault memory of other control units. Stored crash data or non‑erasable internal error codes such as 65535 or 93F9 are also clear indicators.

The airbag warning light is the first and most important sign. It may remain steadily illuminated immediately after starting the engine, or flash for a brief period—say, 30 seconds—before staying lit continuously. This indicates that the safety system is not functioning properly.

Another critical symptom is complete loss of communication. The workshop can no longer access the airbag control unit using diagnostic equipment, making fault diagnosis impossible and pointing to a severe internal malfunction of the module.

The fault memory may contain specific, non‑erasable error codes. Codes like 65535 or 93F9 indicate an internal defect in the control unit. Entries related to insufficient supply voltage, CAN bus errors, or total failure when the unit heats up are also typical fault patterns.

In rarer cases, accompanying symptoms may appear, such as a non‑functioning clock, a flashing engine warning light, or persistent issues with the driver’s airbag—even after the coil spring has already been replaced.

In which vehicles is the control unit A2C15939904 installed?

The airbag control unit with part number A2C15939904 is primarily used in the third generation of the Peugeot Partner. At Airbag24, we repair this control unit for models from the 2018 model year onward, including newer facelift versions introduced from 2024 onwards.

Specifically, this component is installed in the following models and series:

- Peugeot Partner III (model years 2018–2024)

- Peugeot Partner III Facelift (model years 2024–present)

Since the part numbers 9653190880, 9803916880, and 9823741280 are considered synonyms, repairs are also applicable to these variants, as they are often technically identical or very similar.

How does the repair of A2C15939904 at Airbag24 work?

The repair begins with the professional removal of the control unit from the vehicle. After sending it to Airbag24, the device undergoes a systematic analysis during which crash data is erased and defective components on the circuit board are replaced. Final tests ensure full functionality before the unit is returned.

First, a diagnosis should be performed at a specialized workshop to confirm that the fault lies in the control unit itself and not in external components such as cables or sensors. The control unit is then removed and securely packaged.

Upon arrival at Airbag24, a comprehensive inspection is carried out on dedicated test benches. Technicians read the internal fault memory to identify the exact cause. The most common step is professionally erasing the stored crash data, effectively restoring the control unit to like-new condition.

If a hardware defect is detected, faulty components—such as capacitors, microcontrollers, or other parts on the circuit board—are located and replaced with new, high-quality spare parts. Following repairs, calibration and a final functional test ensure proper operation. We provide 2 years' statutory liability for defects on every repair.