U2072 – Control Module Communication Bus Off.

The ODBII code U2072 indicates a communication issue where a control module is not able to communicate over the vehicle’s communication bus, often due to a fault in the module or wiring.

The severity of ODBII code U2072 is moderate to severe.

Common Causes For: U2071 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
• Software issues or firmware corruption
• Intermittent electrical issues
• Faulty or incompatible aftermarket parts
• Low battery voltage or power supply issues

Common misdiagnosis for U2072 Control Module Communication Bus Off.

• Faulty control module
• Wiring issues
• Poor ground connections
• Corrupted software/firmware
• Faulty sensors
• Battery or power supply issues
• Communication network problems
• Intermittent connection issues

Common Troubleshooting Steps

The OBD-II code U2072 indicates a communication issue between control modules in a vehicle, specifically that a control module is “bus off.” This typically means that the module is unable to communicate on the CAN (Controller Area Network) bus due to a fault. 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 context and help identify the root cause of the communication issue.
• Inspect Wiring and Connectors: Visually inspect the wiring and connectors associated with the control modules involved. Look for signs of damage, corrosion, loose connections, or broken wires.
• Pay special attention to the CAN bus wiring, which typically consists of a twisted pair of wires.
• Check Power and Ground: Ensure that the control module in question has proper power and ground connections. Use a multimeter to verify voltage and ground integrity.
• Check the fuses related to the control modules and replace any that are blown.
• Test the Control Module: If possible, test the control module itself. This may involve using a scan tool to check for communication with the module or performing a bench test if the module can be removed.
• If the module is faulty, it may need to be repaired or replaced.
• Inspect the CAN Bus: Use an oscilloscope or a CAN bus analyzer to check the signal integrity on the CAN bus. Look for proper voltage levels and signal patterns.
• Check for termination resistors (typically 120 ohms) at both ends of the CAN bus. If they are missing or faulty, it can cause communication issues.
• Check for Interference: Look for any aftermarket devices or modifications that may be interfering with the CAN bus communication. This includes alarms, stereo systems, or other electronic devices.
• Perform a Network Scan: Use a professional scan tool to perform a network scan of all modules on the CAN bus. This can help identify which module is causing the communication failure.
• 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 Technical Service Bulletins (TSBs): Check for any manufacturer-specific TSBs related to the U2072 code or communication issues. There may be known fixes or updates available.
• Seek Professional Help: If the issue persists after performing these steps, it may be necessary to consult a professional mechanic or automotive technician who has experience with CAN bus systems and advanced diagnostic tools. By following these troubleshooting steps, you can systematically identify and resolve the underlying issue causing the U2072 code.