Airbag control unit with part number 5WK49251

What is the function of the airbag control unit 5WK49251?

The airbag control unit with part number 5WK49251 is the central control module for the occupant safety system (SRS) in the Hyundai Santro AH2. It analyzes data from the acceleration sensors to detect a collision and, if necessary, rapidly deploys airbags and pretensioners.

As the “brain” of the safety system, this module continuously monitors and evaluates signals from various crash sensors throughout the vehicle.

In the event of a collision, the control unit determines within milliseconds whether and how extensively to activate the restraint systems, thereby ensuring optimal protection for vehicle occupants.

Why does the airbag control unit 5WK49251 fail?

Failure of the 5WK49251 control unit is usually due to two main causes: stored crash data following an accident that locks the unit, or internal electronic defects on the circuit board. These hardware malfunctions often result in error codes such as “component defective” or “airbag internal error.”

The most common reason for repair is the retention of crash data in the internal memory (EEPROM/Flash) after an airbag has deployed. The control unit enters a locked state to prevent reuse without proper inspection, making it impossible to clear the airbag warning light.

Another cause is internal hardware defects. Faulty components like voltage regulators, driver circuits, or memory chips can disrupt functionality, leading to persistent error codes indicating a fault within the control unit itself.

In some cases, communication with diagnostic equipment also becomes impossible, signaling more severe damage to the internal electronics. External factors such as moisture or voltage issues in the vehicle’s electrical system can exacerbate these problems.

Since part numbers 95910-0Y000, 95910-0Y001, 95910-0Y002, and 285001003 are functionally identical, they exhibit the same typical failure patterns in practice and can likewise be repaired.

How do you recognize a defect in the 5WK49251?

The clearest symptom of a faulty 5WK49251 control unit is the permanently illuminated airbag warning light (SRS symbol) on the instrument panel. Additionally, the control unit may become inaccessible to diagnostic tools, or specific error codes such as “airbag internal error” may be stored.

If the airbag warning light remains on and cannot be cleared even after resetting the fault memory, a defect in the control unit is highly suspected—this is a clear indication that the system is no longer operational.

Another critical symptom is the inability to perform diagnostics. When a workshop attempts to read the fault memory, no connection to the airbag control unit can be established.

Following a collision, messages like “refer to the manual” often appear, while the fault memory contains entries such as “component defective” or “crash data stored.” These errors can only be resolved through specialized repair of the control unit.

In which vehicles is the 5WK49251 control unit installed?

The airbag control unit with part number 5WK49251, along with its equivalent variants 95910-0Y000, 95910-0Y001, 95910-0Y002, and 285001003, is specifically designed for the Hyundai Santro of the AH2 generation. At Airbag24, we offer repairs exclusively for these vehicle models.

At Airbag24, we repair control units with part number 5WK49251 and the aforementioned equivalent numbers for the following model:

Hyundai Santro AH2 (model years approximately 2018–2022)

How is the 5WK49251 control unit professionally repaired?

At Airbag24, the control unit undergoes a professional repair process that includes a detailed initial analysis, erasing crash data from the internal memory, and restoring the electronics by replacing defective components. A final functional test on the test bench ensures full operability.

After careful removal and shipment to Airbag24, the control unit first undergoes a comprehensive incoming inspection, during which the fault memory is read and the internal electronics are thoroughly analyzed.

The core of the repair consists of two steps. First, crash data stored after an accident is erased from the memory chip (EEPROM/Flash), unlocking the control unit.

Subsequently, electronic restoration takes place: defective components on the circuit board responsible for errors such as “airbag internal error” are identified and replaced with new, high-quality parts. Damage caused by short circuits or faulty solder joints is also rectified.

After repair, the control unit is tested on a specialized test bench to ensure that communication and self-diagnosis are functioning perfectly again. You receive 2 years' statutory liability for defects on the completed repair.