U2185 – Module Communication Failure

The ODBII code U2185 indicates a communication failure between modules in a vehicle’s network, suggesting that one or more electronic control units (ECUs) are not able to communicate properly with each other.

The severity of ODBII code U2185 is moderate.

Common Causes For: U2184 U2184: CAN Bus Communication Failure

• Faulty wiring or connectors
• Failed control module
• Poor ground connections
• Corroded terminals
• Communication network issues (e.g., CAN bus problems)
• Software glitches or outdated firmware
• Intermittent electrical issues
• Battery voltage problems
• Aftermarket modifications or installations affecting communication

Common misdiagnosis for U2185 U2185: “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 module failures in the network

Common Troubleshooting Steps

The OBD-II code U2185 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 module(s). Look for signs of damage, corrosion, or loose connections.
• Pay special attention to the ground connections, as poor grounding can lead to communication issues.
• Check Power Supply:
• Ensure that the affected module is receiving the proper voltage and ground. Use a multimeter to check the power supply to the module.
• If the module is not receiving power, trace the wiring back to the fuse box and check for blown fuses or damaged wiring.
• Test the Module:
• If possible, test the affected module by swapping it with a known good module (if applicable) to see if the problem persists.
• Some modules may have self-diagnostic capabilities; consult the service manual for specific testing procedures.
• Check for Communication:
• Use a scan tool to check if you can communicate with the affected module. If you cannot, it may indicate a problem with the module itself or the communication network.
• Check the communication lines (CAN bus, LIN bus, etc.) for continuity and proper signal levels.
• Inspect the CAN Bus:
• If the vehicle uses a CAN bus system, check for any short circuits or open circuits in the CAN wiring.
• Use an oscilloscope or a CAN bus analyzer to monitor the data lines for proper communication signals.
• Look for Interference:
• Check for any aftermarket devices or modifications that may interfere with the vehicle’s communication network.
• Remove or disconnect any non-factory equipment to see if the issue resolves.
• Update Software/Firmware:
• Check if there are any software updates available for the vehicle’s control modules. Sometimes, communication issues can be resolved with a software update.
• Clear Codes and Test Drive:
• After performing the above checks and repairs, clear the trouble codes using the OBD-II scanner and take the vehicle for a test drive to see if the code returns.
• Consult Service Manual:
• Refer to the vehicle’s service manual for specific diagnostic procedures related to the U2185 code and the affected module(s). If the issue persists after following these steps, it may be necessary to consult a professional technician or dealership for further diagnosis and repair.