U2373 – Control Module Communication Bus Off.

The ODBII code U2373 indicates a communication issue where a control module is not able to communicate properly on the vehicle’s communication bus, often due to a fault in the module or wiring.

The severity of ODBII code U2373 is moderate to severe.

Common Causes For: U2372 Invalid Data Received from the Transmission Control Module (TCM)”.

• Faulty control module
• Damaged wiring or connectors
• Poor ground connections
• Communication bus interference
• Software issues or bugs
• Low battery voltage
• Corroded terminals
• Faulty or damaged sensors on the bus

Common misdiagnosis for U2373 Control Module Communication Bus Off.

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

Common Troubleshooting Steps

The OBD-II code U2373 indicates a communication issue on the control module communication bus, specifically that a module is “off” or not communicating properly. Here are some common troubleshooting steps to diagnose and resolve this issue:

• Check for Other Codes: Start by scanning the vehicle for any other diagnostic trouble codes (DTCs). Other codes may provide additional context or indicate related issues.
• Inspect Wiring and Connectors:
• Visually inspect the wiring and connectors associated with 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 which control module is reporting the U2373 code. This may require consulting the vehicle’s service manual or wiring diagrams.
• If possible, test the control module for proper operation. This may involve checking for power and ground at the module, as well as verifying that it is functioning correctly.
• Test the Communication Bus:
• Use a scan tool to monitor the communication on the bus. Check if other modules are communicating properly.
• If you have access to an oscilloscope, you can check the signal integrity on the communication lines (CAN, LIN, etc.) to ensure they are functioning correctly.
• Check for Short Circuits or Open Circuits:
• Use a multimeter to check for short circuits or open circuits in the communication lines. This may involve testing continuity and resistance in the wiring.
• Inspect for Interference:
• Look for any aftermarket devices or modifications that may interfere with the communication bus. This includes alarms, stereo systems, or other electronic devices.
• Update or Reprogram Control Modules:
• In some cases, a software update or reprogramming of the control module may be necessary. Check with the manufacturer for any available updates.
• Clear Codes and Test Drive:
• After performing any repairs or adjustments, clear the codes using a scan tool 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 U2373 code for your specific vehicle make and model. Manufacturers may have specific recommendations or known issues.
• Seek Professional Help:
• If the issue persists after performing these 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 U2373 code.