2015 Infiniti Q50 Steering Control Module: A Guide to the 3-Part DAS System & Programming

Understanding the 2015 Q50 Direct Adaptive Steering (DAS) System

The 2015 Infiniti Q50 equipped with Direct Adaptive Steering (DAS) uses a complex, multi-part electronic system. Unlike traditional hydraulic or electric power steering, the DAS system is managed by three separate but interconnected control modules. These modules work in concert to control steering angle and effort. When one module fails, it can disrupt the entire system. Due to this interconnected design, technicians often recommend replacing all three modules as a set to ensure compatibility and prevent future issues.

The three modules are typically located:

• Behind the glove box inside the cabin.
• In the engine bay, near the passenger side front wheel well.
• In the engine bay, near the driver side front wheel well.

Known Issues, Recalls, and Technical Service Bulletins (TSBs)

The early generation of the DAS system was subject to several recalls and service campaigns aimed at improving its reliability through software updates.

• NHTSA Recall 16V-430 (Infiniti Campaign R1610): This major safety recall affected 2014-2016 Q50 models. A software error in the Direct Adaptive Steering ECU could cause a loss of steering responsiveness or a change in the turning radius immediately after starting the vehicle. The official remedy was for Infiniti dealers to reprogram the ECU software free of charge.
• Infiniti TSB ITB15-035 (Campaign P5323): This voluntary service campaign was issued for 2014-2015 Q50 Hybrid models in certain cold-weather states. It involved reprogramming the DAS system and replacing the 12-volt battery to address potential malfunctions in cold climates.
• Infiniti TSB ITB14-009 (Campaign P4204): Specifically for some 2014 Q50 models, this campaign involved the complete replacement and reprogramming of all three DAST control modules, highlighting the system's complexity.

Symptoms of a Failing Steering Control Module

Failure within the DAS system can manifest in several ways, ranging from annoying to critical.

• Heavy or Stiff Steering: The most common symptom is a sudden or intermittent loss of power steering assist, making the wheel very difficult to turn, especially at low speeds. This happens when the system reverts to its mechanical backup.
🎬 See how replacing a faulty steering control unit fixes stiff Q50 steering
• DAS System Warning Light: 🎬 Watch this demonstration of a Q50 experiencing electronic steering issues A specific warning light on the instrument cluster will illuminate, indicating a fault has been detected within the Direct Adaptive Steering system.
• Inconsistent Steering Feel: The steering might feel normal one moment and then suddenly become light, heavy, or unpredictable without warning.
• Steering Wheel Not Centered: The system may lose its calibration, resulting in the steering wheel being off-center even when driving straight.

Associated OBD-II Diagnostic Trouble Codes (DTCs)

A professional scan tool capable of reading Infiniti-specific codes is required for accurate diagnosis. Common codes include:

• C1138: This code directly indicates a malfunction has been detected in the Direct Adaptive Steering system.
• C13C0 / C13C2: These codes can help technicians pinpoint which of the three modules (DAST 1, 2, or 3) is the source of the fault.
• U-codes (e.g., U1001): These are communication codes that indicate a loss of signal between modules.

Buying a Used Steering Control Module

Purchasing a used module for the 2015 Q50 requires careful attention to detail due to the complexity of the DAS system.

• Match Part Numbers Exactly: The initial data specifies part number 28505-4GG1A. It is critical to match this number precisely. Because the system uses three modules, it's often best to purchase them as a matched set from the same donor vehicle.
• Verify Production Dates: This module is specific to vehicles manufactured between November 1, 2014, and September 30, 2015. Ensure the donor vehicle falls within this range.
• Inspect for Damage: Check the module and its connectors for any signs of physical damage, corrosion, or water intrusion.
• Programming is Required: A used module is not a plug-and-play part. You must factor in the cost and logistics of having it programmed to your vehicle after installation.
• Why Used OEM is the Only Option: Aftermarket manufacturers do not produce replacements for this highly specialized, software-integrated system. A new OEM module set can be prohibitively expensive, making a quality used OEM set the only practical repair alternative.

Programming and Calibration Requirements

This module absolutely requires professional programming and configuration after installation. This procedure cannot be performed by a typical DIY mechanic or independent shop without the specific Infiniti diagnostic tool.

1. Installation: The physical replacement of the module(s) is performed.
2. Connect Specialized Tools: An Infiniti dealer or a specialist with a genuine CONSULT-III Plus diagnostic tool must connect to the vehicle. A standard OBD-II scanner will not work.
3. Module Configuration: The technician performs a "Module Replacement" or "Configuration" procedure. This involves writing the vehicle's VIN and other specific data to the new module(s), allowing them to communicate with the rest of the car. This process must be done for all three DAS modules.
4. Calibration: After configuration, a steering angle sensor calibration and other system initializations are performed to ensure the system operates correctly.

Replacement Cost Comparison

The cost to repair the DAS system can be significant, primarily due to the price of the modules and the need for specialized labor.

Frequently Asked Questions (FAQ)