Airbag control unit with part number MB875327

What is the function of the airbag control unit MB875327?

The airbag control unit with part number MB875327 is the central SRS module (Supplemental Restraint System) for older Mitsubishi models. Its primary task is to monitor crash sensors and, in the event of an accident, to trigger the airbags and seatbelt pretensioners to ensure occupant safety.

As an original OEM component, it is specifically designed for vehicles such as the Mitsubishi Lancer CB. It continuously processes data from acceleration sensors and determines within milliseconds whether a collision has occurred that requires activation of the restraint systems.

After deployment, the unit permanently stores the crash data, which results in the system being locked and necessitates repair or replacement.

What defects occur in the MB875327 control unit?

The most common defect of the MB875327 is the permanent storage of crash data after an accident or misfire, which locks the system. Other typical issues include internal electronic faults that cause the airbag warning light to remain illuminated, as well as communication problems where the control unit becomes unresponsive via the OBD interface.

A central issue is the locking of the control unit following airbag deployment. The so‑called crash data is written to the internal memory and cannot be erased using standard diagnostic tools, requiring professional repair.

Another frequent symptom is a persistently illuminated SRS warning light on the instrument cluster, even without an actual accident. This indicates an internal fault within the control unit itself, such as problems with the sensors or the internal power supply.

Communication failures are also a well‑known symptom. In such cases, the workshop cannot establish a connection to the SRS module to read fault codes or perform diagnostics.

During diagnosis, error codes like B1209 (SRS control unit test mode malfunction) or B1402 (ground fault in the driver’s airbag circuit) are often detected, pointing to specific system issues. Note that an alternative, verified OEM part number for this component is MR551246DPB.

How can you recognize a defect in the MB875327?

A defective MB875327 airbag control unit primarily manifests as a permanently illuminated airbag warning light (SRS lamp) on the dashboard. Another clear indication is that the control unit becomes unreachable during vehicle diagnostics via the OBD port or refuses to communicate.

The most obvious and common symptom is the SRS warning light that fails to turn off after the engine starts. This alerts the driver that the entire airbag system is non‑functional and would not deploy in the event of a crash.

In the workshop, the defect often shows up when diagnostic tools cannot connect to the control unit. Any attempt to read fault codes or check the system fails, indicating a serious internal malfunction.

Even if communication is impossible, the root cause may lie in stored crash data. After an incident, the unit enters a locked state and denies further communication until it is professionally reset.

In which vehicles is the MB875327 control unit installed?

The MB875327 airbag control unit is primarily used in Mitsubishi models from the 1990s. Its most common application is in the Mitsubishi Lancer CB series. Alternatively, it can also be found in the Mitsubishi Galant-7 (Type E50). At Airbag24, we repair this control unit for the aforementioned models.

At Airbag24, we have successfully refurbished the MB875327 control unit for the following models:

Mitsubishi: Lancer CB (model years 1991–2000)

In addition, confirmed applications exist for other vehicles such as the Mitsubishi Galant-7 (Type E50, model years 1993–1996), particularly with 2.0-liter engines.

For a successful repair, it is crucial that the part number on the removed control unit exactly matches MB875327, as electrical and electronic components are model‑specific.

How does Airbag24 repair the MB875327?

At Airbag24, the submitted MB875327 control unit undergoes a professional initial inspection. Our technicians then erase the stored crash data and address any electronic faults. Following successful refurbishment, the unit passes a functional test before being returned to you with 2 years’ statutory liability for defects.

The first step is to remove the defective control unit from the vehicle. A preliminary diagnosis at a workshop to confirm the fault is recommended.

After sending it to Airbag24, our technicians perform a thorough analysis to identify the root cause of the issue. The focus is on erasing crash data and inspecting the internal electronics.

The repair involves resetting the internal memory and refurbishing the hardware to restore full functionality. The goal is to permanently deactivate the airbag warning light and ensure system readiness.

Finally, each repaired control unit is tested on specialized test benches to verify proper operation. We provide 2 years' statutory liability for defects on every repair performed.