U2735 – Control Module Communication Bus Fault

The ODBII code U2735: Control Module Communication Bus Fault indicates a problem with the communication between control modules in a vehicle, suggesting that one or more modules are not properly transmitting or receiving data on the communication bus.

The severity of ODBII code U2735 is generally considered moderate to severe.

Common Causes For: U2734 U2734: Control Module Communication Bus Fault

• Faulty control module
• Damaged wiring or connectors
• Poor ground connections
• Corroded terminals
• Intermittent electrical connections
• Software issues or bugs
• Faulty communication bus (CAN bus) components
• Low battery voltage or power supply issues

Common misdiagnosis for U2735 U2735: Control Module Communication Bus Fault

• Faulty control module
• Wiring issues or shorts
• Corroded connectors
• Power supply problems
• Software glitches or updates needed
• Faulty sensors
• Incorrectly installed aftermarket components
• Grounding issues

Common Troubleshooting Steps

The OBD-II code U2735 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 or Open Circuits: Use a multimeter to check for continuity in the communication lines. Look for any short circuits or open circuits that could disrupt communication.
• Test Control Modules: If possible, test the individual control modules for proper operation. This may involve using specialized diagnostic tools or software.
• If a specific module is suspected to be faulty, consider replacing it or reprogramming it if necessary.
• 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 Tool Communication: Use a scan tool to communicate with each control module individually. If some modules respond while others do not, it may indicate a problem with the non-responding modules.
• Battery and Power Supply Check: Ensure that the vehicle’s battery is in good condition and that the voltage is within the normal range. Low voltage can cause communication issues.
• Check the fuses related to the control modules and communication bus.
• Software Updates: Check if there are any software updates available for the vehicle’s control modules. Sometimes, manufacturers release updates to fix 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 returns.1
• Consult Technical Service Bulletins (TSBs): Look for any TSBs related to the specific make and model of the vehicle. Manufacturers may have documented solutions for known issues.1
• Professional Diagnosis: If the issue persists after performing the above steps, consider seeking help from a professional mechanic or dealership with experience in diagnosing communication issues. By following these steps, you should be able to identify and resolve the underlying cause of the U2735 code.