U2065 – Control Module Communication Bus Off.

The ODBII code U2065 indicates a communication issue where a control module is not able to communicate on the vehicle’s communication bus, often due to a fault in the module or wiring.

The severity of ODBII code U2065 is moderate to severe.

Common Causes For: U2064 Control Module Communication Bus Off.

• Faulty control module
• Damaged wiring or connectors
• Poor ground connections
• Communication bus short circuit
• Open circuit in the communication bus
• Corroded connectors
• Intermittent electrical issues
• Software or firmware issues in the control module
• Low battery voltage or power supply issues
• Faulty or incompatible aftermarket components

Common misdiagnosis for U2065 Control Module Communication Bus Off.

• Faulty control module
• Wiring issues
• Poor ground connections
• Corrupted software/firmware
• Faulty connectors or terminals
• Battery or power supply issues
• Intermittent communication faults
• Other communication bus errors (e.g., CAN bus issues)

Common Troubleshooting Steps

The OBD-II code U2065 indicates a communication issue on the control module communication bus, specifically that a control module is “off” or not responding. This can be caused by various issues, including wiring problems, module failures, or issues with the communication bus itself. Here are some common troubleshooting steps to diagnose and resolve the U2065 code:

• 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.
• Inspect Wiring and Connectors: Visually inspect the wiring and connectors related to the control modules on the communication bus. Look for signs of damage, corrosion, or loose connections.
• Pay special attention to the ground connections, as poor grounding can lead to communication issues.
• Check the Control Modules: Identify the control modules on the communication bus and check if they are functioning properly. This may involve checking for power and ground at the module connectors.
• If possible, test the modules individually to see if they respond correctly.
• Test the Communication Bus: Use a multimeter or an oscilloscope to check the communication signals on the bus. Look for proper voltage levels and signal integrity.
• If you have access to a scan tool that can monitor live data, check if the modules are communicating with each other.
• Inspect for Short Circuits or Open Circuits: Check for any short circuits or open circuits in the communication lines. This may involve using a multimeter to test continuity and resistance in the wiring.
• Check for Interference: Ensure that there are no aftermarket devices or modifications that could be interfering with the communication bus. This includes things like alarms, stereo systems, or other electronic devices.
• Reset the Codes: After performing inspections 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.
• Update or Reprogram Modules: In some cases, control modules may need to be updated or reprogrammed. Check with the manufacturer for any available updates.
• Replace Faulty Components: If a specific control module is identified as faulty, it may need to be replaced. Ensure that the replacement module is compatible with your vehicle.
• Consult Technical Service Bulletins (TSBs): Check for any TSBs related to the U2065 code for your specific vehicle make and model. Manufacturers may have specific recommendations or known issues.1
• 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 automotive electronics and communication systems. By following these troubleshooting steps, you can systematically identify and resolve the underlying issue causing the U2065 code.