Airbag control unit with part number 4759012

What is the function of Airbag Control Unit 4759012?

The airbag control unit with part number 4759012 is the central control module of the Supplemental Restraint System (SRS) in the second-generation Chrysler LHS (1998–2001). It processes signals from crash sensors, deploys airbags and seatbelt pretensioners in the event of a collision, and permanently stores relevant crash data in its internal memory.

As an SRS ECU (Supplemental Restraint System Electronic Control Unit), it continuously monitors all safety‑related components of the vehicle, including front and side airbags, seatbelt pretensioners, seat occupancy detection, and connected impact sensors.

In the event of a collision, the 4759012 control unit determines within milliseconds which restraint systems need to be activated to provide optimal occupant protection. After deployment, the unit locks out system functions and records crash data to ensure a safe vehicle inspection.

Why does Airbag Control Unit 4759012 fail?

The most common cause of failure for control unit 4759012 is the storage of crash data after an accident, which can block functionality. Other reasons include internal hardware defects in electronic components, as well as external factors such as loose connectors under the seats or cable breaks.

Following a crash, crash data is stored in the control unit’s memory—a safety feature that prevents reuse without proper inspection and reset. Once this occurs, the unit becomes locked and must be professionally reset.

External factors also frequently contribute to issues. Loose connectors beneath the front seats—often caused by seat adjustments—can disrupt communication with sensors or side airbags. Similarly, cable breaks or moisture can damage the control unit’s electronics.

An internal hardware defect, often diagnosed with error code B1111 (control unit malfunction), may also be responsible. Components such as capacitors or sensors on the circuit board itself could fail.

How do you recognize a fault in control unit 4759012?

A fault in control unit 4759012 primarily manifests as a continuously illuminated airbag warning light (SRS lamp). Additionally, the unit often cannot be read via OBD diagnostics and reports internal errors like B1111. Accompanying symptoms, such as a flashing engine check light, may also appear.

The clearest indication is the airbag warning light on the instrument cluster, which fails to extinguish after a few seconds upon starting the vehicle and remains lit continuously.

Another clear symptom is the lack of communication with diagnostic tools. When a workshop attempts to read the fault memory, no response is received from the control unit, suggesting a severe internal fault or blockage due to crash data.

In some cases, specific error codes such as B1111 (control unit malfunction), faults in the crash sensor circuit, or messages related to seat airbags are displayed. Unusual secondary effects—such as a malfunctioning clock when exposed to heat or a flashing engine check light—have also been observed in this model when paired with a defective SRS control unit.

In which vehicles is control unit 4759012 installed?

The airbag control unit with part number 4759012 is specifically designed for the second-generation Chrysler LHS. At Airbag24, we repair this control unit for the following model, where the described faults frequently occur:

- Chrysler LHS, second generation (model years 1998–2001)

What are the benefits of repairing 4759012?

Repairing control unit 4759012 offers significant cost savings of up to 70% compared to purchasing a new unit, which can range from €400 to €750. The repaired unit is immediately ready for use (plug-and-play), and the work performed comes with 2 years' statutory liability for defects.

The financial advantage is the primary consideration. While a new factory‑original control unit entails substantial costs, repair provides an economical and budget‑friendly alternative.

Since the vehicle’s original control unit is refurbished, there is no need for time‑consuming reprogramming or relearning procedures. After installation, the system is fully functional right away, saving both time and additional workshop expenses.

How is control unit 4759012 professionally repaired?

Professional repair at Airbag24 begins with an initial inspection and reading of the fault memory. Stored crash data is then erased, defective electronic components on the circuit board are replaced, and the unit is restored to its factory settings. A final functional test ensures quality.

After you send us the removed control unit, our technicians analyze the root cause of the fault. First, we check whether crash data is stored or if there is a hardware defect.

The core of the repair involves erasing the crash data and performing a complete software reset to the factory‑default state. If necessary, defective components such as capacitors or sensors on the circuit board are professionally replaced.

Following the repair, the control unit undergoes an extensive functional test to ensure it communicates flawlessly with the vehicle again and correctly manages all safety functions. We provide 2 years' statutory liability for defects on every repair.