U1737 – Module Communication Failure

The ODBII code U1737 indicates a “Module Communication Failure,” meaning there is a problem with communication between the vehicle’s control modules, often due to a wiring issue, a faulty module, or a network problem.

The severity of ODBII code U1737 is moderate.

Common Causes For: U1736 U1736: TCM Communication Failure

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

Common misdiagnosis for U1737 U1737: “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 U1737 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 additional trouble codes. Sometimes, other codes can provide context or lead to the root cause of the communication failure.
• 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 ground connections, as poor grounding can lead to communication issues.
• Check Power Supply: Ensure that the affected modules are receiving the proper voltage. Use a multimeter to check the power supply to the modules.
• Test Communication Lines:
• Use a scan tool to check the communication lines (CAN bus, LIN bus, etc.) for continuity and proper voltage levels.
• If you have access to an oscilloscope, you can check the signal waveforms on the communication lines to ensure they are functioning correctly.
• Inspect Modules:
• If possible, check the affected module for any signs of physical damage or water intrusion.
• If you suspect a specific module is faulty, you may need to replace it or test it in another vehicle to confirm its functionality.
• Reset the Modules: Sometimes, resetting the modules can clear temporary communication issues. Disconnect the battery for a few minutes, then reconnect it and see if the code returns.
• Check for Software Updates: Ensure that the vehicle’s software is up to date. Sometimes, manufacturers release updates that can resolve communication issues.
• Look for Intermittent Issues: If the problem is intermittent, try to replicate the conditions under which the code appears. This can help identify specific triggers for the communication failure.
• Consult Wiring Diagrams: Refer to the vehicle’s service manual for wiring diagrams to understand the communication network and identify any potential issues.
• Professional Diagnosis: If the issue persists after performing these steps, it may be necessary to consult a professional technician who has experience with the specific vehicle make and model. They may have access to specialized diagnostic tools and knowledge of common issues. By following these steps, you should be able to identify and resolve the underlying cause of the U1737 code.