U2273 – Control Module Communication Bus Off.

The ODBII code U2273 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 U2273 is moderate to severe.

Common Causes For: U2272 Control Module Communication Bus Off.

• Faulty control module
• Damaged wiring or connectors
• Poor ground connections
• Short circuits in the communication bus
• Corroded terminals
• Software issues or bugs in the control module
• Interference from aftermarket devices
• Low battery voltage or power supply issues

Common misdiagnosis for U2273 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 U2273 indicates a communication issue on the control module communication bus, specifically that a module is “off” or not responding. This can be caused by various factors, including wiring issues, module failures, or problems with the communication bus itself. 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. This can provide more context about the issue.
• Inspect Wiring and Connectors: Visually inspect the wiring and connectors related to the control modules. Look for signs of damage, corrosion, or loose connections.
• Pay special attention to the communication bus wires (CAN bus, LIN bus, etc.) and ensure they are intact.
• Check Power and Ground: Verify that the affected control module has proper power and ground connections. Use a multimeter to check voltage and continuity.
• Ensure that the fuses related to the control modules are intact.
• Test the Control Module: If possible, test the affected control module by swapping it with a known good module (if applicable) to see if the issue persists.
• Some vehicles may allow for module reprogramming or resetting, which can sometimes resolve communication issues.
• Inspect the Communication Bus: Use a scan tool to monitor the communication bus for activity. Check for any irregularities in the data being transmitted.
• If you have access to an oscilloscope, you can check the signal integrity on the communication lines.
• Check for Interference: Look for any aftermarket devices or modifications that may interfere with the communication bus, such as alarms, remote starters, or other electronic accessories.
• Perform a Network Test: Some advanced scan tools can perform a network test to identify which module is not communicating properly. This can help pinpoint the issue.
• Clear Codes and Test Drive: After performing any repairs or adjustments, clear the trouble codes and take the vehicle for a test drive to see if the code returns.
• Consult Technical Service Bulletins (TSBs): Check for any TSBs related to the specific make and model of the vehicle. Manufacturers may have issued guidance on common issues related to communication bus problems.
• Seek Professional Help: If the issue persists after performing the above steps, it may be necessary to consult a professional technician or dealership for further diagnosis. By following these steps, you should be able to identify and resolve the underlying issue causing the U2273 code.