Airbag control unit with part number 603602600

What is the function of the airbag control unit 603602600?

The airbag control unit with part number 603602600 is the central control module for the occupant protection system in the Peugeot 407. As an OEM component, it is identical to parts numbered 9655880880, 9655880780, and 603554600. Its primary task is to process sensor data so that, in the event of a crash, the airbags and seatbelt pretensioners are deployed precisely and promptly.

During normal driving, the unit continuously monitors all connected components, such as crash sensors, seat occupancy mats, seatbelt pretensioners, and airbag modules. It performs self-tests and ensures that the entire restraint system remains operational at all times. If a fault occurs in the system, this is indicated by activating the airbag warning light on the instrument panel.

After a collision, the unit stores so‑called crash data. This information permanently locks the control unit to prevent reuse without professional inspection and repair. A professional repair restores the unit to its factory settings, making it fully functional again.

Why does the control unit 603602600 fail? Typical defects.

The most common cause of failure for control unit 603602600 is stored crash data following a collision, which locks the device. In addition, internal electronic faults can lead to communication issues or persistent error codes such as B1000 that cannot be cleared. These defects also occur in the equivalent variants 9655880880, 9655880780, and 603554600.

A major source of errors is the storage of crash data. Even after minor collisions where the airbags do not deploy, the control unit may set an internal lock flag. This condition is irreversible and can only be resolved through specialized electronic repair, which involves erasing the data and resetting the software.

Internal electronic defects are another frequent cause. These may manifest as software glitches, communication problems with the diagnostic tester, or specific error codes like B1000. Often, faulty components on the circuit board or defective solder joints trigger these malfunctions, requiring targeted repairs at the component level.

How do you recognize a defect in the airbag control unit 603602600?

A defect in control unit 603602600 primarily shows up as a permanently or intermittently illuminated airbag warning light on the dashboard. Other clear indicators include persistent error codes stored in the fault memory that cannot be cleared, as well as complete refusal of communication from the control unit during diagnostic attempts.

The most noticeable symptom is the active airbag warning light. It signals a fault in the restraint system and does not turn off after the engine starts. This is a safety‑related issue that requires immediate diagnosis.

During workshop diagnostics, a defect often appears as error codes indicating an internal control unit malfunction, such as code B1000. Such errors cannot be cleared using standard diagnostic tools and point to a deep‑seated problem in the device’s software or hardware.

Another clear sign is the presence of stored crash data. If the vehicle has been involved in an accident, the diagnostic tool will report that the control unit is locked. In this case, repair is essential to restore full functionality of the airbag system.

In which vehicles is the control unit 603602600 installed?

The airbag control unit with part number 603602600 and its equivalent numbers was specifically developed for the Peugeot 407 series. It was used across the entire production run, including the facelift models, in both sedan and station wagon (SW) versions.

At Airbag24, we repair control unit 603602600 for the following models:

Peugeot 407 I (model years 2004–2008)

Peugeot 407 I Facelift (model years 2006–2012)

Peugeot 407 SW I (model years 2004–2008)

Peugeot 407 SW I Facelift (model years 2006–2012)

If your part number differs slightly, please contact us directly, as many other variants can also be repaired.

What are the advantages of repair over buying a new unit?

Repairing the original control unit is the most economical and technically sensible solution. Not only can you save up to 70% compared to purchasing a new expensive part, but you also avoid time‑consuming reprogramming at an authorized service center. Moreover, refurbishment is an environmentally friendly alternative.

A key advantage is that the vehicle‑specific original coding remains fully intact. After installation, the repaired control unit can be used immediately (plug-and-play), without the need for complicated and costly programming or relearning by the vehicle.

Financially, the savings are substantial. A new control unit from the manufacturer is often disproportionately expensive. Repair restores full functionality at a fraction of that cost. Additionally, every repair comes with 2 years' statutory liability for defects.

How does the repair of control unit 603602600 work?

The repair process is designed for maximum efficiency and transparency. After removal at your workshop, the defective control unit is sent to us. At Airbag24, we perform professional electronic refurbishment, restoring the device to near‑new condition. It is then thoroughly tested and returned with 2 years’ statutory liability for defects.

Upon receipt at Airbag24, our technicians conduct a comprehensive analysis on specialized test benches. The core of the repair involves reprogramming the software and completely erasing stored crash data, thereby restoring the device to its original factory settings.

If diagnostics reveal defects in physical components, these are replaced at the component level. Following successful refurbishment, each control unit undergoes a final functional test. You receive the unit back along with a detailed test report confirming the successful repair.