U2165 – Module Communication Failure

The ODBII code U2165: Module Communication Failure indicates that there is a communication issue between the vehicle’s control modules, meaning one or more modules are not able to send or receive data properly.

The severity of ODBII code **U2165: Module Communication Failure** is generally considered moderate to severe.

Common Causes For: U2009: Control Module Communication Bus Fault

• Faulty wiring or connectors
• Failed control module
• Corroded or damaged pins
• Poor ground connections
• Intermittent communication issues
• Software or firmware issues
• Low battery voltage
• Electrical interference
• Faulty CAN bus system
• Incompatible or aftermarket modules

Common misdiagnosis for U2165: Module Communication Failure

• Faulty wiring or connectors
• Defective control module
• Software issues or firmware corruption
• Battery or power supply problems
• Grounding issues
• Intermittent communication issues
• Incorrectly configured or programmed modules
• Faulty sensors or actuators

Common Troubleshooting Steps

The OBD-II code **U2165: Module Communication Failure** indicates that there is a communication issue between the vehicle’s control modules. This can be caused by various factors, including wiring issues, faulty modules, or problems with the vehicle’s network. Here are some common troubleshooting steps to diagnose and resolve this issue:

• Check for Additional Codes: Use an OBD-II scanner to check for any other trouble codes that may be present. This can provide more context about the issue and help identify which module is having communication problems.
• Inspect Wiring and Connectors:
• Visually inspect the wiring and connectors associated with the affected module(s). Look for signs of damage, corrosion, or loose connections.
• Pay special attention to the ground connections, as poor grounding can lead to communication failures.
• Check the Module:
• If a specific module is indicated in the trouble code, check that module for proper operation. This may involve testing the module’s power and ground circuits.
• If possible, swap the suspected faulty module with a known good one to see if the problem persists.
• Test the Communication Network:
• Use a multimeter or an oscilloscope to check the communication lines (CAN bus, LIN bus, etc.) for proper voltage levels and signals.
• Look for short circuits, open circuits, or noise on the communication lines.
• Inspect the Fuses:
• Check the fuses related to the affected modules. A blown fuse can interrupt communication between modules.
• Reset the Modules:
• Sometimes, simply resetting the modules by disconnecting the battery for a few minutes can clear temporary communication issues.
• Update Software/Firmware:
• Check if there are any software or firmware updates available for the vehicle’s modules. Sometimes, communication issues can be resolved with an update.
• Check for Interference:
• Ensure that there are no aftermarket devices (like alarms, radios, or other electronic accessories) that could be interfering with the vehicle’s communication network.
• Consult Wiring Diagrams:
• Refer to the vehicle’s service manual for wiring diagrams and communication protocols to better understand how the modules communicate and where potential issues may lie.
• Professional Diagnosis:
• If the issue persists after performing the above steps, consider seeking help from a professional mechanic or dealership with advanced diagnostic tools. By following these steps, you can systematically identify and resolve the underlying cause of the U2165 code.