U2937 – Control Module Communication Bus Fault

The ODBII code U2937: Control Module Communication Bus Fault indicates a communication issue between control modules in a vehicle, suggesting that one or more modules are not properly communicating over the vehicle’s data bus.

The severity of ODBII code U2937 is moderate.

Common Causes For: U2936 U2936: Control Module Communication Bus Fault

• Faulty control module
• Damaged wiring or connectors
• Poor ground connections
• Corroded terminals
• Short circuits in the communication bus
• Intermittent electrical connections
• Software issues or bugs in the control module
• Faulty or incompatible aftermarket components
• Low battery voltage or power supply issues
• Environmental factors (moisture, heat, etc.) affecting connections

Common misdiagnosis for U2937 U2937: Control Module Communication Bus Fault

• Faulty control module
• Wiring issues
• Poor ground connections
• Corroded connectors
• Battery or power supply problems
• Software glitches or updates needed
• Other communication bus faults (e.g., CAN bus issues)
• Sensor malfunctions
• Intermittent electrical connections
• Faulty diagnostic tools or procedures

Common Troubleshooting Steps

The OBD-II code U2937 indicates a “Control Module Communication Bus Fault.” This code typically points to a problem with the communication between various control modules in the vehicle. Here are some common troubleshooting steps to diagnose and resolve this issue:

• Check for Additional Codes: Use an OBD-II scanner to check for any other trouble codes that may be present. Sometimes, multiple codes can provide more context for the issue.
• Inspect Wiring and Connectors: Visually inspect the wiring and connectors associated with the control modules. Look for signs of damage, corrosion, or loose connections.
• Pay special attention to the communication bus wires (CAN bus) for any signs of wear or damage.
• Check for Short Circuits: Use a multimeter to check for short circuits in the communication lines. Ensure that the wires are not shorted to ground or to each other.
• Test Control Modules: If possible, test the control modules involved in the communication bus. This may involve checking for proper operation or replacing modules if they are found to be faulty.
• Inspect Ground Connections: Ensure that all ground connections for the control modules are secure and free of corrosion. Poor grounding can lead to communication issues.
• Check 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.
• Scan for Communication Issues: Use a professional-grade scan tool to monitor the communication between modules. This can help identify which module is not communicating properly.
• Perform a Network Test: Some advanced scan tools can perform a network test to check the integrity of the communication bus. This can help pinpoint the issue.
• Update Software/Firmware: Check if there are any software or firmware updates available for the control modules. Sometimes, updating the software can resolve communication issues.
• Clear Codes and Test Drive: After performing the above checks and repairs, clear the trouble codes and take the vehicle for a test drive to see if the code reappears.1
• Consult Service Manual: Refer to the vehicle’s service manual for specific diagnostic procedures related to the communication bus and control modules.1
• Seek Professional Help: If the issue persists after performing these steps, it may be necessary to consult a professional mechanic or technician who specializes in automotive electronics. By following these troubleshooting steps, you can systematically identify and resolve the underlying cause of the U2937 code.