Audi Sport Differential Module (4H0907163B) Failure: Diagnosis & Replacement for A6, S6, A7, S7, RS7, A8, S8 (2014-2018)

What is the Sport Differential Control Module?

The part numbers 4H0907163A and 4H0907163B identify the electronic control unit for the Audi Sport Differential. This is an advanced system found on high-performance Quattro models, including the 2014-2018 Audi S6, 2014-2018 Audi S8, 2016-2018 Audi S7, 2016-2018 Audi RS7, 2014-2018 Audi A8 Quattro, 2014-2018 Audi A6 Quattro, and 2016-2018 Audi A7 Quattro. This module is the dedicated computer that makes the sport differential work, providing a noticeable improvement in handling over the standard open rear differential.

It's important to clarify that this is not a Body Control Module (BCM). While sometimes mislabeled, its sole function is to manage the rear sport differential. Failure of this module will not affect lights, locks, or windows, but it will disable the torque vectoring feature.

Symptoms of a Failing Sport Differential Module

Failure of this module, or a related component in the sport differential system, will typically result in clear warnings on the instrument cluster.

• "Sport Differential: system fault" Warning Light: This is the most common and direct symptom. The warning will appear on the driver information display, often accompanied by an audible chime.
🎬 Watch: See how multiple system failures appear on the dashboard.
• Traction Control (ESC) Light May Illuminate: Since the sport differential is tied into the vehicle's dynamics and stability systems, a fault in one can trigger warnings in the other.
• Inability to Deactivate Traction Control: Some owners report that when the sport differential fault is active, the button to disable traction control becomes unresponsive.
• Limp Mode or Reduced Power: In some cases, especially under hard acceleration, a fault in the system can cause the car to enter a reduced power state, often called "limp mode".
• No Change in Normal Driving: For everyday commuting, most drivers will not notice a difference in how the car drives, as the sport differential is most active during aggressive cornering. The car is safe to drive, but the performance handling benefit will be gone.

Common OBD-II and VAG-COM Fault Codes

A proper diagnosis requires scanning the vehicle with an Audi-specific tool like VCDS (VAG-COM) or ODIS. Common codes associated with this system include:

• C1004 & C1005: Oil Pressure and Temperature Sensor Implausible Signal. These codes often point to issues with the sensors on the differential itself, but can also be triggered by a faulty module.
• 02095 - Component Protection Active: This code will appear if you install a used control module without having it programmed to the vehicle. The module will not function until this is resolved.

Common Causes of Failure

• Water Intrusion: On many of these models, the control module is located in the trunk area. Leaky trunk seals or clogged drains can lead to water pooling and submerging the module, causing terminal corrosion and internal failure.
• Internal Electronic Failure: Like any complex electronic device, the module can fail internally over time due to heat cycles and vibration.
• Sensor or Pump Failure: Sometimes the module itself is fine, but it is reporting a fault due to a failure in another part of the system, such as the differential's hydraulic pump or pressure sensors.
• Low Battery Voltage: A weak or failing vehicle battery can sometimes cause spurious electronic faults, including a temporary sport differential fault warning.

Programming and Component Protection: The #1 Issue

This is the most critical factor when replacing this module. Audi utilizes a security system called Component Protection (CP) to link electronic modules to a specific vehicle's VIN.

• Programming is Required: A new or used Sport Differential Control Module must be programmed to your vehicle after installation. If you simply swap the module, it will trigger a "Component Protection Active" fault and will not work.
• Who Can Program It?: This programming requires an online connection to Audi's servers using their proprietary ODIS software with a secure GeKo login. 🎬 Watch: How technicians use ODIS to remove Component Protection. This means the programming must be done by:
  • An official Audi dealership.
  • A qualified independent shop that specializes in German vehicles and subscribes to the ODIS service.
• DIY Is Not Possible for Programming: While you can physically install the module yourself, you cannot complete the job without professional programming. There is no known offline or DIY method to remove Component Protection 🎬 Watch: How to code out the sport differential system entirely. for this module.

Buying a Used Sport Differential Module

Buying a used module is a great way to save money, but you must be aware of the programming requirements. A used module is not "plug-and-play."

Inspection Checklist:

1. Match the Part Number: You must match the OEM part number exactly. The primary part numbers are 4H0907163A and the later revision 4H0907163B.
2. Inspect for Water Damage: Look closely at the housing and electrical connector pins. Any signs of white or green crusty corrosion mean the module was exposed to moisture and should be avoided.
3. Check for Physical Damage: Ensure the case and connectors are not cracked or broken.
4. Factor in Programming Costs: Remember that the price of the used part is not the final cost. You must budget for 1-2 hours of labor at a dealer or specialist shop to have Component Protection removed.

Cost of Replacement

Prices can vary based on location and supplier, but here is a general estimate:

Known Issues, TSBs, and Recalls

As of this writing, there are no specific NHTSA recalls for this control module. However, there are related Technical Service Bulletins (TSBs):

• TSB 2064024: Addresses an oil leak from the top of the differential due to missing sealing caps on the pressure limiting valves. This requires removing the differential to repair.
• TSB 2059129 / 2074859: Discusses noises and vibrations during tight turns. This is often considered a normal characteristic but can sometimes be improved with a special differential fluid change. This TSB relates to the center differential, but is relevant to drivetrain noise diagnosis.

Frequently Asked Questions (FAQ)