U2108 – Lost Communication with Vehicle Control Module.

The ODBII code U2108 indicates a loss of communication with the vehicle control module, suggesting that the module is not responding or is unable to communicate with other modules in the vehicle’s network.

The severity of ODBII code U2108 is generally considered moderate to high.

Common Causes For: U2107 Lost Communication with Vehicle Control Module.

• Faulty Vehicle Control Module (VCM)
• Damaged wiring or connectors
• Poor ground connections
• Corrupted software or firmware
• Faulty communication network (CAN bus issues)
• Low battery voltage
• Intermittent electrical connections
• Other module failures affecting communication

Common misdiagnosis for U2108 Lost Communication with Vehicle Control Module.

• Faulty wiring or connectors
• Defective vehicle control module (VCM)
• Malfunctioning engine control module (ECM)
• Issues with the body control module (BCM)
• Problems with the transmission control module (TCM)
• Faulty sensors or actuators
• Battery or charging system issues
• Software or firmware glitches
• Corrupted diagnostic trouble codes (DTCs)
• Communication network issues (CAN bus problems)

Common Troubleshooting Steps

The OBD-II code U2108 indicates a “Lost Communication with Vehicle Control Module.” This code typically points to a communication issue between the vehicle’s control modules, which can be caused by various factors. Here are some common troubleshooting steps to diagnose and resolve the issue:

• Check for Additional Codes: Use an OBD-II scanner to check for any other trouble codes that may be present. Other codes can provide additional context for the problem.
• Inspect Wiring and Connectors:
• Visually inspect the wiring and connectors related to the affected control module. Look for signs of damage, corrosion, or loose connections.
• Pay special attention to the wiring harnesses that connect to the control modules.
• Check Power and Ground:
• Ensure that the control module has the proper power supply and ground. Use a multimeter to check for voltage at the module’s power and ground pins.
• If there is no power or ground, trace the wiring back to the fuse box or battery to identify the issue.
• Test the Control Module:
• If the wiring and connections are intact, the control module itself may be faulty. If possible, test the module by swapping it with a known good module or using a diagnostic tool to perform a module test.
• Inspect for Short Circuits:
• Check for any short circuits in the wiring that could be causing communication issues. This can be done using a multimeter to test for continuity between wires that should not be connected.
• Check for Interference:
• Look for any aftermarket devices or modifications that may interfere with the communication between modules. This includes alarm systems, stereo systems, or other electronic devices.
• Perform a Network Test:
• Use a scan tool capable of performing a network test to check the communication between modules. This can help identify which module is not communicating properly.
• Clear Codes and Test Drive:
• After performing the above checks and repairs, clear the trouble codes using the OBD-II scanner and take the vehicle for a test drive to see if the code returns.
• Consult Service Manual:
• Refer to the vehicle’s service manual for specific diagnostic procedures related to the U2108 code and the control modules involved.
• Seek Professional Help:
• If the issue persists after performing these steps, it may be necessary to consult a professional mechanic or technician who has experience with the specific vehicle make and model. By following these troubleshooting steps, you can systematically identify and resolve the underlying issue causing the U2108 code.