Airbag control unit with part number KEAD 57K30 C

What is the function of the KEAD 57K30 C airbag control unit?

The airbag control unit with part number KEAD 57K30 C is the central control module for the Supplemental Restraint System (SRS) in specific Mazda CX-5 models. It monitors all safety‑related sensors, controls the deployment of airbags and seatbelt pretensioners in the event of a crash, and stores irreversible crash data in its internal memory.

As the brain of the passive safety system, this module continuously processes data from acceleration and yaw rate sensors to detect a collision. Once predefined thresholds are exceeded, it sends ignition commands to the relevant pyrotechnic components of the restraint system within milliseconds.

An additional key function is the continuous self‑diagnosis of the entire SRS. The control unit constantly checks the functionality of all connected components, such as airbags, seatbelt pretensioners, and sensors. If faults are detected, the airbag warning light illuminates and an appropriate fault code is stored in memory.

Why does the KEAD 57K30 C airbag control unit fail?

The most common cause of failure for the KEAD 57K30 C is the storage of crash data after an airbag deployment, which permanently locks the device. Other defects arise from physical impacts—such as broken wiring—moisture damage, or loose connectors. Internally, electronic components like chips or capacitors may also fail.

Following a crash involving airbag activation, a so‑called “crash lock” is set in the control unit’s memory. This lock is intentionally implemented by the manufacturer to prevent reuse without professional repair. Simply clearing the fault memory via diagnostic tools is no longer possible in this state.

Electronic malfunctions on the circuit board are another frequent cause. These include faulty microprocessors, defective memory modules (EEPROM), or cold solder joints resulting from aging and thermal stress. External factors such as improper wiring or voltage fluctuations in the vehicle’s electrical system can also damage the control unit.

The KEAD 57K30 C belongs to a family of modules. Technically related or equivalent part numbers that may be used in the same vehicle platforms include: KD4557K30B, KA1C-57-K30A, KR2757K30A, KA1C-57K30, KEAD-57K30-A, KGVT-57K30-C/D, and VC73-57K30.

How do you recognize a defect in the KEAD 57K30 C?

A defective KEAD 57K30 C primarily manifests as a persistently illuminated airbag warning light on the instrument cluster. Often, communication with the control unit via diagnostic tools becomes impossible. The fault memory contains non‑erasable error codes such as “internal error,” “resistance too high,” or CAN bus errors.

The most obvious sign is the continuously lit SRS warning light. It does not turn off after starting the vehicle, indicating a serious, safety‑critical system fault requiring immediate inspection.

Another clear symptom is complete loss of communication. When a workshop attempts to read the fault memory, the diagnostic tool receives no response from the airbag control unit—the module is no longer reachable on the vehicle’s network.

Even when communication is possible, certain fault codes cannot be cleared. This is especially true for entries indicating an internal fault in the control unit or those remaining after a crash involving deployed airbags (e.g., knee airbags) and subsequent component replacement.

In practice, repairability is quite high: faults related to the driver’s airbag that cause a permanently lit lamp are repairable in approximately 99% of cases. Faults affecting the passenger’s airbag—sometimes indicated by the warning light flashing seven times—are less frequently repairable and often require replacing the entire unit.

In which vehicles is the KEAD 57K30 C installed?

The airbag control unit with part number KEAD 57K30 C is mainly used in Mazda vehicles. It is specifically designed for Mazda CX‑5 SUV models from the KE series (2011–2017) and KF series (from 2017 onward), including their respective facelift variants. Airbag24 offers repairs for precisely these models.

At Airbag24, we repair the KEAD 57K30 C for the following specific vehicle series:

Mazda CX‑5 (KE series, model years 2011–2015)

Mazda CX‑5 (KE series facelift, model years 2015–2017)

Mazda CX‑5 (KF series, model years 2017–2021)

Mazda CX‑5 (KF series facelift, from model year 2021 onward)

Is repairing the KEAD 57K30 C worthwhile?

Repairing the KEAD 57K30 C is an economically and technically sensible alternative to costly new purchases. It delivers significant cost savings compared to a new unit, which manufacturers list at around €800 plus VAT. Moreover, the repaired original unit is immediately fully functional and ready for use.

The biggest advantage lies in the significant cost reduction. A professional repair is often up to 70% cheaper than purchasing a new control unit from an authorized workshop. This protects your budget without compromising safety.

Another crucial point is maintaining the vehicle’s original configuration. Since the original control unit is repaired, there is no need for time-consuming re‑coding or reprogramming, which would often be required with a new or used replacement part. Once installed, the repaired unit functions as usual.

Two years' statutory liability for defects is provided on every repair performed. This offers added assurance and underscores the high quality of the restoration, ensuring the control unit fully regains its original functionality.

How does Airbag24 carry out the repair of the KEAD 57K30 C?

At Airbag24, the repair of the KEAD 57K30 C follows a proven, professional process. After removal and shipment, the control unit is first analyzed using specialized diagnostic tools to pinpoint the exact fault. Any defective electronic components are then replaced if necessary. With this control unit, erasing the crash data is often not possible. If the crash data needs to be erased, please contact us briefly before sending the unit in – we will check your part number.

In the first step, a thorough incoming inspection is conducted. Technicians read out the fault memory and simulate the vehicle environment to precisely reproduce the reported symptoms. This ensures that the true cause of the defect is identified.

The core of the repair involves eliminating the root cause of the issue. In cases of hardware defects, faulty components such as processors, capacitors, or memory chips are expertly replaced with new, high‑quality parts. Additionally, all relevant wiring and connectors are inspected.

Following the repair, a comprehensive final test and system calibration take place. The control unit is tested again under real‑world conditions to confirm flawless operation across all functions. Airbag24 provides 2 years' statutory liability for defects on successful repairs.