DTC U0136: Lost Communication with Rear Differential Control Module

Introduction

DTC U0136 is a communication problem that occurs in modern vehicles equipped with advanced electronic control systems. This code indicates that the engine control unit (ECU) has lost communication with the rear differential control module. In this article, we will explore the symptoms, causes, diagnosis, and solutions to address this problem, providing useful insights for auto mechanics.

Symptoms

When the U0136 error code occurs, drivers may notice a variety of symptoms that may vary depending on the vehicle model and the severity of the problem. The most common symptoms include:

  • Warning light on dashboard comes on
  • Malfunctions in the all-wheel drive system or differential
  • Erratic vehicle behavior while driving, especially in low grip conditions
  • Limitation of the stability control system functionality
  • Difficulty changing driving modes (if present)

Cause

The causes of the DTC code U0136 can be many and include:

  • Damaged or poorly connected cables :
    The wires connecting the ECU to the differential control module may be damaged or loose, causing loss of communication.

  • Faulty differential control module :
    An internal fault in the differential control module itself can prevent correct data transmission.

  • Power problems :
    Insufficient or unstable power supply to the differential control module may cause malfunctions.

  • Software issues :
    An error in the control unit software may prevent communication from functioning correctly.

Diagnosis

Diagnosing DTC U0136 requires a systematic approach. The following are the recommended steps:

  1. DTC Code Scan :
    Use an OBD-II diagnostic tool to check for associated DTC codes, such as U0100 (Loss of Communication with ECU), U0121 (Loss of Communication with ABS Control Module), and U0137 (Loss of Communication with Front Differential Control Module).

  2. Visual inspection :
    Check cables and connectors for any signs of wear, corrosion or damage.

  3. Power Check :
    Measure the input voltage to the differential control module to ensure it is within operating range.

  4. Control Module Test :
    If no problems are found in the wiring and power supply, test the differential control module using a simulator or by temporarily replacing it with a working unit.

  5. Software Control :
    Make sure your ECU and differential module software is updated to the latest version available.

Resolution and Repair

Once you have identified the cause of the U0136 error code, you can take the following corrective actions:

  • Cable Repair :
    If any damaged or poorly connected cables are found, repair or replace them.

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

  • Power Correction :
    If there are power problems, troubleshoot by checking fuses, relays, and connections.

  • Software Update :
    If necessary, update the software of both the engine control unit and the differential control module.

  • System Reset :
    After performing repairs, it is advisable to reset the DTC codes and verify that the problem has been resolved.

Insight: Components Involved in Failure

To better understand the DTC U0136 code, it is useful to analyze the mechanical and electrical components involved:

  • Differential Control Module :
    This module manages the rear differential operations and constantly communicates with the ECU to optimize the vehicle performance. Any malfunctions in this module may affect traction and stability.

  • Cables and connectors :
    The quality of cables and connectors is essential for the correct functioning of the system. Deteriorated cables or oxidized connectors can interrupt communication.

  • Engine Control Unit (ECU) :
    This control unit is the brain of the vehicle, coordinating all electronic functions. Its integrity and proper functioning are essential for communication with the differential control module.

Conclusions

DTC U0136 is a common problem in modern vehicles, but with accurate diagnosis and a systematic repair procedure, the problem can be solved effectively. Auto repairers should be prepared to identify the underlying causes and intervene on the affected components to restore the vehicle to normal functionality. Being informed about related DTC codes and associated symptoms can help provide better service and ensure driver safety.

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.