U1394 – Control Module Communication Failure

The ODBII code U1394 indicates a “Control Module Communication Failure,” meaning there is a problem with communication between the vehicle’s control modules, which can affect various systems and functions.

Moderate to Severe.

Common Causes For: U1393 U1393: “Control Module Communication Failure”

• Faulty control module
• Poor electrical connections
• Damaged wiring harness
• Corroded connectors
• Software issues or bugs
• Low battery voltage
• Interference from aftermarket devices
• Faulty CAN bus communication
• Grounding issues

Common misdiagnosis for U1394 U1394: “Control Module Communication Failure”

• Faulty control module
• Wiring issues
• Poor ground connections
• Corrupted software/firmware
• Faulty sensors
• Battery or power supply issues
• Communication network problems (CAN bus issues)
• Intermittent connection faults

Common Troubleshooting Steps

When dealing with OBD-II code U1394, which indicates a “Control Module Communication Failure,” there are several common troubleshooting steps you can follow to diagnose and potentially resolve the issue. Here’s a structured approach:

• 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: **Visual Inspection: Check the wiring and connectors related to the control modules for any signs of damage, corrosion, or loose connections.
• **Repair or Replace: If you find any damaged wires or connectors, repair or replace them as necessary.
• Check Power and Ground: Ensure that the control modules have the proper power supply and ground connections. Use a multimeter to verify voltage and ground continuity.
• Inspect Control Modules: If the vehicle has multiple control modules, check if the affected module is functioning properly. This may involve:
• Testing the module with a scan tool.
• Checking for any signs of physical damage or water intrusion.
• Check for Communication Issues: Use a scan tool to check if the control module can communicate with other modules in the vehicle. If it cannot, there may be a communication bus issue.
• Inspect the CAN (Controller Area Network) bus wiring for shorts, opens, or interference.
• Reset the Codes: Clear the trouble codes using the OBD-II scanner and see if the code returns after a short drive cycle. If it does, further investigation is needed.
• Update Software/Firmware: Check if there are any software updates available for the control modules. Sometimes, manufacturers release updates to fix communication issues.
• Perform a Network Test: If available, use a professional-grade scan tool to perform a network test to check the integrity of the communication network.
• 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 fixes for U1394.
• Seek Professional Help: If the issue persists after performing the above steps, it may be necessary to consult a professional mechanic or technician who has experience with the specific vehicle and its control systems.Conclusion Troubleshooting OBD-II code U1394 requires a systematic approach to identify and resolve communication issues between control modules. By following these steps, you can narrow down the potential causes and work towards a solution.