U1395 – Control Module Communication Failure

The ODBII code U1395 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.

Common Causes For: U1394 U1394: “Control Module Communication Failure”

• Faulty wiring or connectors
• Failed control module
• Poor ground connections
• Corroded or damaged connectors
• Software issues or bugs
• Intermittent electrical issues
• Communication network faults (e.g., CAN bus issues)
• Low battery voltage or power supply issues
• Aftermarket modifications or installations affecting communication
• Faulty sensors or actuators affecting communication pathways

Common misdiagnosis for U1395 U1395: “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

The OBD-II code U1395 indicates a “Control Module Communication Failure.” This code typically suggests 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 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:
• 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 wiring harnesses that connect the modules, as these can be prone to wear and tear.
• Check Power and Ground:
• Ensure that the control modules are receiving proper power and ground. Use a multimeter to check voltage and ground continuity at the module connectors.
• If there is no power or ground, trace the wiring back to the fuse box or battery to identify the issue.
• Test 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.
• Some modules may have self-diagnostic capabilities that can provide additional information.
• Inspect the CAN Bus:
• The communication between control modules often occurs over a Controller Area Network (CAN) bus. Check for any issues with the CAN bus wiring, such as shorts or opens.
• Use a CAN bus scanner to monitor the communication and check for any abnormalities.
• Check for Software Updates:
• Sometimes, communication issues can be resolved with a software update. Check with the vehicle manufacturer for any available updates for the control modules.
• 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 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 issues related to control module communication.
• Seek Professional Help:
• If the issue persists after performing these steps, it may be necessary to consult a professional mechanic or technician who has experience with the specific vehicle and its control systems. By following these troubleshooting steps, you can systematically identify and resolve the underlying cause of the U1395 code.