U2477 – Control Module Communication Failure

The ODBII code U2477: Control Module Communication Failure indicates a problem with communication between control modules in the vehicle, suggesting that one or more modules are not able to send or receive data properly.

The severity of ODBII code **U2477: Control Module Communication Failure** is generally considered moderate to severe.

Common Causes For: U2470: Control Module Communication Error

• Faulty control module
• Poor or damaged wiring/connectors
• Corroded terminals
• Software issues or bugs
• Low battery voltage
• Interference from aftermarket devices
• Faulty communication network (CAN bus issues)
• Grounding issues

Common misdiagnosis for U2477: Control Module Communication Failure

• 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 protocol failures

Common Troubleshooting Steps

The OBD-II code **U2477: Control Module Communication Failure** indicates a communication issue between control modules in a vehicle’s network. This can be caused by various factors, including wiring issues, faulty modules, or problems with the vehicle’s communication protocols. 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. This can provide more context about 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 CAN (Controller Area Network) bus wiring, as this is often where communication issues arise.
• Test the Control Modules:
• If possible, test the affected control module(s) to ensure they are functioning correctly. This may involve using specialized diagnostic tools or swapping with a known good module.
• Check Power and Ground:
• Verify that the control modules have the proper power supply and ground connections. Use a multimeter to check voltage and continuity.
• Inspect for Short Circuits:
• Check for any short circuits in the wiring that could be causing communication failures. This may involve testing individual wires for continuity and resistance.
• Look for Intermittent Issues:
• Sometimes, communication failures can be intermittent. Pay attention to when the code appears (e.g., during specific driving conditions) and check for any patterns.
• Update Software/Firmware:
• Check if there are any software or firmware updates available for the control modules. Sometimes, manufacturers release updates to fix communication issues.
• Clear Codes and Test Drive:
• After performing any repairs or inspections, clear the trouble codes and take the vehicle for a test drive to see if the code returns.
• Consult Technical Service Bulletins (TSBs):
• Look for any TSBs related to the specific make and model of the vehicle. Manufacturers may have documented common issues and solutions for communication failures.
• 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 can systematically identify and resolve the underlying cause of the U2477 code.