Airbag control unit with part number 4686602AD

What is the function of Airbag Control Unit 4686602AD?

The Airbag Control Unit 4686602AD is the central control module for passive safety systems in specific Chrysler and Dodge vehicles. Its primary task is to analyze crash data in real time, ensuring that vital restraint systems—such as airbags and seatbelt pretensioners—are activated precisely and reliably in the event of a collision.

This module serves as the brain of the entire Supplemental Restraint System (SRS). It continuously receives data from various crash and acceleration sensors distributed throughout the vehicle. Based on this information, the control unit assesses the severity and nature of an impact.

On the basis of this analysis, the unit makes split-second decisions about whether and which safety systems should be deployed to maximize occupant protection. Thus, it controls not only the front airbags but also the entire network of passive safety devices.

Why does Control Unit 4686602AD fail?

The most common causes of failure for Control Unit 4686602AD include internal hardware defects, errors in the internal EEPROM memory, and crash data stored after an accident that locks the module. Communication faults with other vehicle components are also typical failure modes.

A very frequent reason for repair is the storage of crash data following a collision. After activation, the control unit deliberately locks itself to force a system check. Error code B120C (internal memory overflow) may appear when multiple crash events have been recorded.

Internal hardware defects represent another major cause. Error code B1100 directly indicates such a defect within the physical module. Errors like B1010 (internal memory error) or B1020 (power supply fault) likewise point to issues with electronic components on the circuit board.

Communication problems manifest as error codes such as B1000 (control unit communication error) or U0151 (loss of communication with the restraint system control unit). These can stem from malfunctions within the module itself or from wiring issues. Software defects or calibration data problems are often indicated by code B1120.

How do you recognize a defect in Control Unit 4686602AD?

A defect in Control Unit 4686602AD typically becomes apparent through a permanently illuminated airbag warning light on the dashboard. Another clear symptom is that the control unit cannot be accessed via a diagnostic tool or displays specific error codes such as B1000, B1100, or U0151.

The primary and unmistakable sign is the activated airbag warning light. It fails to extinguish after starting the vehicle, signaling a malfunction in the safety system that requires immediate inspection.

During diagnostics at the workshop, it often becomes evident that no communication can be established with the airbag control unit. The diagnostic tool either reports an error or simply fails to detect the module within the vehicle’s network, indicating a serious internal defect.

Alternatively, specific error codes may be stored in the fault memory, directly referencing the airbag module. The codes mentioned in the previous section are typical examples that technicians read out during troubleshooting.

In which vehicles is Control Unit 4686602AD installed?

The Airbag Control Unit with part number 4686602AD is primarily found in models from Chrysler and Dodge. It has been used across various vehicle generations in the Chrysler Town & Country, as well as in the Dodge Grand Caravan and Caravan, providing broad coverage across these model lines.

At Airbag24, we repair Control Unit 4686602AD for the following specific models and series:

Chrysler: Town & Country (GS, RT), Town & Country EV (RT), and the TC by Maserati (Q, 1989–1991).

Dodge: Grand Caravan (1st generation 1984–1990, 3rd generation 1996–2000, 4th generation 2001–2007, 5th generation 2008–2020), including S, NS, and RT variants. Also covered are the 2nd-generation Dodge Caravan and its S and NS variants.

How is Control Unit 4686602AD repaired?

After sending the removed Control Unit 4686602AD to Airbag24, a professional analysis and repair process begins. This includes erasing crash data, fixing hardware defects, and restoring the correct firmware. Following a final test, the module is fully functional again.

Before removing the control unit, the vehicle battery must be disconnected for at least 10 minutes. The module is usually located in the center console. After careful removal, the device is securely packaged and shipped to Airbag24.

At Airbag24, the control unit is first subjected to an initial inspection. This is followed by professional repair, which—depending on the nature of the fault—may involve erasing crash data using specialized diagnostic tools, repairing internal hardware defects, or replacing damaged memory modules.

After successful refurbishment, each control unit undergoes a comprehensive functional test on a dedicated test bench, ensuring that all functions have been fully restored. We provide 2 years' statutory liability for defects on every repair.