Airbag control unit with part number P04671774AC

What is the function of the airbag control unit P04671774AC?

The airbag control unit with part number P04671774AC is an Original Equipment Manufacturer (OEM) control module from Chrysler/Mopar. It serves as the central brain of the occupant protection system, primarily in models such as the Dodge Neon and Chrysler Neon. Its main tasks include processing sensor data, triggering airbags and seatbelt pretensioners during a crash, and storing relevant crash data.

The unit continuously communicates with the vehicle’s various crash sensors. In the event of a collision, it determines within milliseconds which restraint systems need to be activated to provide optimal protection for occupants. After a deployment, it permanently stores the crash data, preventing further use without professional repair.

In addition, the control unit acts as a crucial interface for diagnostic tools. It allows workshops to check the system status, read out fault codes, and verify the proper functioning of all safety‑related components.

Why does the control unit P04671774AC fail? Typical defects.

The most common reason for failure of the P04671774AC control unit is the storage of crash data after an accident, which permanently locks the device. Other causes include internal hardware defects resulting from electrical disturbances such as overvoltage or insufficient battery voltage, as well as external mechanical issues—such as cable breaks under the seats or defective seatbelt buckles.

After an airbag deployment, an irreversible entry is written into the control unit’s memory. This lockout is a manufacturer‑imposed safety feature that cannot be removed using standard diagnostic equipment and requires specialized repair to restore functionality.

Internal electronic faults are another frequent source of problems. Short circuits on the circuit board—often indicated by error code B1B06 (internal hardware short circuit)—or damage caused by voltage spikes can render the unit inoperable. Defective memory chips or processors may also lead to total failure.

Often, the root cause lies not in the control unit itself but in the vehicle’s surrounding environment. Wiring defects—especially around the front seats during seat adjustments—or faulty sensors and seatbelt buckles can produce symptoms that mistakenly point to a defective control unit. It is known that several variants exist, such as P04671774AB and P04671774AC.

How do you recognize a defect in the P04671774AC?

A defect in the P04671774AC airbag control unit almost always manifests as a permanently illuminated airbag warning light on the instrument cluster. Another clear indication is the lack of communication with the control unit via an OBD diagnostic tool. Stored fault codes such as “control unit defective” or “B1B06” often confirm an internal malfunction.

The most noticeable sign is the airbag warning lamp. It either remains lit continuously after turning on the ignition, or it briefly illuminates for about 30 seconds upon starting the vehicle before staying on permanently. This signals a critical system error that should be inspected immediately.

A severe symptom is complete loss of communication. In such cases, workshops can no longer access the control unit to read fault codes or perform diagnostics—the unit no longer responds to requests from diagnostic equipment.

If communication is still possible, specific fault codes can indicate the nature of the problem. Entries like “control unit defective,” errors related to side‑impact sensors, or the particular code B1B06 for an internal short circuit are typical signs of hardware damage within the control unit.

Following an accident—in which, for example, the knee airbag has deployed—the control unit becomes locked. The stored crash data prevents a simple reset, and the airbag light stays illuminated until the unit undergoes professional repair.

In which vehicles is the P04671774AC control unit installed?

The Chrysler/Mopar airbag control unit P04671774AC was specifically developed for certain models of the Chrysler and Dodge brands. It is predominantly found in various generations and trims of the Chrysler Neon and Dodge Neon, including the PL and SX series.

At Airbag24, we repair the P04671774AC control unit for the following models, among others:

Chrysler: Neon 1st generation (1994–1999), Neon 2nd generation (1999–2002), Neon 2nd generation facelift (2002–2005), Neon PL and Neon SX.

Dodge: Neon 1st generation (1994–1999), Neon 2nd generation (1999–2002), Neon 2nd generation facelift (2002–2005), Neon PL and Neon SX.

How is the P04671774AC professionally repaired?

Professional repair of the P04671774AC involves a detailed analysis, erasing stored crash data using specialized tools, and restoring the hardware. Unlike a simple software reset, this process also inspects electronic components and replaces them if necessary to ensure full functionality and safety.

At Airbag24, repairs follow a proven procedure. After removal—performed beneath the center console and strictly with the battery disconnected—the control unit is sent for analysis. A diagnostic report from your workshop can expedite this process.

Our technicians conduct an initial inspection to pinpoint the exact cause of the fault. Next, all permanently stored crash data is completely erased, returning the device to its factory settings. For hardware defects caused by short circuits or overvoltage, affected components on the circuit board are expertly replaced.

Upon completion of the repair, the control unit undergoes a comprehensive functional test. A major advantage of this repair is that no re‑coding at the dealership is required. After installation, the system performs a self‑test, and the airbag warning light extinguishes as expected. You receive 2 years' statutory liability for defects on the completed repair.