U2086 – Module Communication Failure

The ODBII code U2086 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 U2086 is moderate.

Common Causes For: U2085 U2085: “Module Communication Failure”

• Faulty wiring or connectors
• Failed or malfunctioning control module
• Poor ground connections
• Corrupted software or firmware in the module
• Intermittent communication issues
• Low battery voltage or power supply issues
• Electrical interference or noise
• Damaged or corroded pins in connectors

Common misdiagnosis for U2086 U2086: “Module Communication Failure”

• Faulty wiring or connectors
• Defective control module
• Software issues or updates needed
• Battery or power supply problems
• Grounding issues
• Intermittent communication issues
• Other communication protocol failures

Common Troubleshooting Steps

The OBD-II code U2086 indicates a “Module Communication Failure,” which typically means that there is a problem with communication between various control modules in the vehicle. 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 modules are receiving proper power and ground. Use a multimeter to check voltage and ground continuity.
• If a module is not receiving power, trace the circuit back to the fuse box and check for blown fuses or damaged wiring.
• Test the Modules:
• If possible, test the affected modules individually to ensure they are functioning correctly. This may involve using specialized diagnostic tools or software.
• If a module is found to be faulty, it may need to be repaired or 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.
• Reset the Codes:
• After performing any repairs or inspections, clear the trouble codes using the OBD-II scanner and take the vehicle for a test drive to see if the code returns.
• Check for Software Updates:
• Sometimes, communication issues can be resolved with a software update for the affected modules. Check with the vehicle manufacturer for any available updates.
• Consult Technical Service Bulletins (TSBs):
• Look for any TSBs related to the specific make and model of the vehicle. Manufacturers may have issued guidance on common communication issues.
• Professional Diagnosis:
• If the issue persists after performing the above steps, consider seeking help from a professional mechanic or dealership with experience in diagnosing module communication issues. By following these steps, you can systematically identify and resolve the underlying cause of the U2086 code.