DTC U0135: Lost communication with front differential control module

Introduction

DTC U0135 indicates a loss of communication between the engine control unit (ECU) and the front differential control module. This issue can significantly affect the performance of the vehicle, especially in driving conditions where the four-wheel drive system plays a crucial role. In this article, we will explore the symptoms, causes, diagnosis methods and solutions to address the U0135 error code, providing useful information for auto repairers.

Symptoms

Loss of communication with the front differential control module can manifest itself through various symptoms, including:

  • Warning light activated on the dashboard (usually the "check engine" or "AWD" light)
  • Abnormal four-wheel drive behavior
  • Difficulty switching from front-wheel drive to all-wheel drive
  • Vehicle stability system malfunctions
  • Slowing or delayed throttle response, especially under load conditions

Cause

The causes behind the DTC U0135 code can vary, but some of the more common ones include:

  • Wiring problems :
    Damaged, worn, or disconnected cables can interrupt communication between the ECU and the differential control module.

  • Control module malfunction :
    The front differential control module may be faulty due to faulty internal components or an electronic malfunction.

  • Power problems :
    Insufficient or irregular power supply can lead to communication problems between the various modules.

  • Electromagnetic interference :
    Poorly designed electronic devices or circuits can cause interference, compromising communication.

  • Software Corruption :
    An incorrect update or software malfunction may prevent the modules from functioning correctly.

Diagnosis

Diagnosing the U0135 error code requires a systematic approach and the use of advanced diagnostic tools. Here are some steps to follow:

  1. Scanning for error codes :
    Use an OBD-II scanner to read the fault codes stored in the ECU. Check for other related codes, such as U0140 (Lost communication with transmission control module) or U0101 (Lost communication with engine control module).

  2. Checking the wiring :
    Visually inspect the wires and connections between the ECU and the differential control module. Look for signs of wear, corrosion or disconnections.

  3. Power Test :
    Use a multimeter to check power and ground to the differential control module.

  4. Control module check :
    Check the operation of the differential control module, performing specific tests if available.

  5. Communication test :
    Use diagnostic tools to test communication between the various modules. This may include using an oscilloscope to analyze communication signals.

Resolution and repair

Once you have identified the cause of the U0135 error code, you can proceed with the following repair actions:

  • Wiring Repair :
    If any damaged or disconnected cables are found, repair or replace them.

  • Replacing the control module :
    If the differential control module is defective, replace it with a new or remanufactured unit.

  • Fixing Power Issues :
    Make sure the module is receiving adequate and stable power. This may involve replacing faulty fuses or relays.

  • Software Update :
    If the problem is software related, you may need to update the firmware of the ECU or control module.

  • Interference check :
    If interference is suspected, perform tests to identify sources of noise and resolve any design issues.

Insight: Mechanical and electrical components involved

In the context of the U0135 error code, it is essential to understand the components involved in the front differential control system. These include:

  • Differential Control Module :
    Responsible for managing the distribution of torque between the front and rear wheels, it allows for optimisation of traction in different driving conditions.

  • Engine Control Unit (ECU) :
    Coordinates the operations of various modules in the vehicle, ensuring that information is exchanged correctly to optimize overall performance.

  • Cables and connectors :
    Essential to ensure reliable communication between the various modules. Their integrity is essential for the correct functioning of the system.

  • Position sensors :
    These sensors provide data on wheel position and steering angle, information that is crucial to the operation of the all-wheel drive system.

Conclusions

DTC U0135 presents a significant challenge in diagnosing and troubleshooting the AWD system. A thorough understanding of the symptoms, causes and diagnostic techniques is essential for auto repairers. With a methodical approach and the use of appropriate diagnostic tools, this problem can be identified and resolved, thus ensuring proper vehicle operation and driver safety. Proper management of the electronic and mechanical components involved is essential to maintaining the reliability and performance of the AWD system in the long term.

Important
Not all OBD2 codes used by one manufacturer are used by other brands, and may not have the same meaning.
The information presented here is for informational purposes only. We are not responsible for any actions you take on your vehicle. If you have any concerns about repairing your vehicle, please contact your repair shop.