U2085 – Module Communication Failure

The ODBII code U2085 indicates a communication failure between modules in the vehicle’s network, suggesting that one or more control modules are not able to communicate properly with each other.

The severity of ODBII code U2085 is moderate.

Common Causes For: U2084 U2084: Instrument Cluster Communication Loss

• Faulty wiring or connectors
• Failed control module
• Poor ground connections
• Corroded or damaged connectors
• Communication network issues (e.g., CAN bus problems)
• Software or firmware issues
• Low battery voltage or power supply issues
• Intermittent electrical faults

Common misdiagnosis for U2085 U2085: “Module Communication Failure”

• Faulty wiring or connectors
• Defective control module
• Software issues or updates needed
• Power supply problems
• Grounding issues
• Intermittent communication issues
• Other module failures (e.g., ABS, BCM)
• Corrupted data or configuration errors

Common Troubleshooting Steps

The OBD-II code U2085 indicates a “Module Communication Failure,” which typically means that there is a problem with communication between the vehicle’s control modules. Here are some common troubleshooting steps to diagnose and resolve this issue:

• Check for Other 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 affected modules. Look for signs of damage, corrosion, or loose connections.
• Pay special attention to the wiring harnesses that connect the modules, as these can be prone to wear and tear.
• Check Power and Ground:
• Ensure that the affected module(s) are receiving proper power and ground. Use a multimeter to check voltage and ground continuity.
• If the module is not receiving power, trace the circuit back to the fuse box and check for blown fuses or damaged wiring.
• Test the Affected Module:
• If possible, test the affected module to see if it is functioning correctly. This may involve bench testing or swapping with a known good module.
• If the module is faulty, it may need to be replaced.
• Check for Communication Issues:
• Use a scan tool to check if the affected module is communicating with other modules. If it is not, there may be a communication bus issue.
• Inspect the CAN (Controller Area Network) bus wiring for shorts, opens, or interference.
• Look for Software Updates:
• Check if there are any software updates available for the vehicle’s 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.
• Monitor the vehicle’s performance and check for any symptoms that may indicate ongoing issues.
• Consult Technical Service Bulletins (TSBs):
• Look for any TSBs related to the U2085 code for your specific vehicle make and model. Manufacturers may have documented common issues and solutions.
• Professional Diagnosis:
• If the issue persists after performing the above steps, consider seeking help from a professional mechanic or dealership. They may have specialized diagnostic tools and experience with your specific vehicle. By following these steps, you can systematically diagnose and potentially resolve the U2085 code.