Airbag control unit with part number 000 820 72 26 (01)

What is the function of Airbag Control Unit 000 820 72 26 (01)?

The airbag control unit with part number 000 820 72 26 (01), often manufactured by companies such as Bosch or Temic, serves as the central control module for the Supplemental Restraint System (SRS) in classic Mercedes-Benz models. It processes signals from sensors and is responsible for deploying airbags and tightening seat belts in the event of a crash.

This control unit is a critical safety component that continuously monitors all system components, ensuring that passive safety systems operate correctly when needed.

It was primarily installed in the Mercedes-Benz E-Class models W124 and C124 and is specifically designed to match their system architecture. Its primary task is to detect a collision and activate the restraint devices within milliseconds.

Why does control unit 000 820 72 26 (01) fail?

The most common cause of failure for control unit 000 820 72 26 (01) is the storage of crash data after an accident, which prevents further functionality. Another typical issue is an internal fault within the device, manifesting as persistent, non‑erasable error codes such as B1000, 001, or 1 (function faulty).

Even after minor collisions, permanent entries are stored in the control unit’s memory. These “crash data” lock the system to prevent unintended re‑deployment and require a diagnostic check.

An internal defect—often related to the memory or internal logic—can render the control unit unable to reset itself. Diagnostic tools then cannot clear these error codes, despite the mechanical SRS components remaining intact.

The unit is also known under Bosch reference number 0 285 001 078. Similar control units exhibiting comparable symptoms carry part numbers like 001 820 21 26, 003 820 73 10, or 004 820 18 10, indicating a shared technical foundation.

How can you recognize a fault in control unit 000 820 72 26 (01)?

A malfunctioning control unit 000 820 72 26 (01) typically manifests as a continuously or intermittently illuminated airbag warning light (SRS symbol) on the instrument cluster. During workshop diagnostics, specific error codes such as B1000 (control unit defective) or 1 (function faulty) cannot be cleared.

The most obvious and unmistakable sign is the active SRS warning light, alerting the driver that the entire restraint system is inoperative and may fail to deploy in the event of a crash.

When diagnosed using appropriate testing equipment, the problem often appears as a communication failure or as error codes pointing to an internal defect within the control unit. Attempts to erase these errors prove unsuccessful, directing attention squarely toward the control unit itself.

In which vehicles is control unit 000 820 72 26 (01) installed?

The airbag control unit 000 820 72 26 (01) is primarily fitted in classic Mercedes-Benz E-Class models, specifically the W124 sedan and the C124 coupe. Airbag24 offers professional repair services for these vehicles.

At Airbag24, we specialize in repairing this control unit for the following vehicle models:

Mercedes-Benz E-Class C124 Coupe (1987–1996)

Mercedes-Benz E-Class W124 Sedan (1984–1995)

Although some databases list other models such as the Sprinter or the SL R129, this control unit’s primary focus remains on classic E-Class vehicles. We always recommend verifying the part number directly on the removed unit for definitive identification.

How is control unit 000 820 72 26 (01) professionally repaired?

Repair of control unit 000 820 72 26 (01) at Airbag24 centers on addressing electronic root causes. This includes professionally erasing stored crash data and reprogramming the memory to resolve internal faults. Following this, the unit’s full functionality is thoroughly tested and backed by 2 years’ statutory liability for defects.

After submitting the removed control unit to Airbag24, our technicians conduct a detailed analysis to pinpoint the source of the fault, focusing on the error codes stored in the memory and the condition of the internal electronics.

The core of the repair process involves targeted reprogramming: stored crash data is safely deleted, allowing the control unit to be recognized as fully operational once again. Internal issues triggering error code B1000 are resolved at the chip level.

Repair represents a significantly more cost-effective alternative to purchasing a new unit, restoring the original SRS system’s functionality. We provide 2 years' statutory liability for defects on every completed repair.