U1650 – Module Communication Failure

The ODBII code U1650 indicates a “Module Communication Failure,” meaning there is a problem with communication between the vehicle’s control modules, often due to a fault in the wiring, connectors, or the modules themselves.

The severity of ODBII code U1650 is generally considered moderate.

Common Causes For: U1649 Lost Communication with Body Control Module (BCM)”.

• Faulty wiring or connectors
• Failed or malfunctioning control module
• Poor ground connections
• Corrupted software or firmware in the module
• Interference from aftermarket devices
• Low battery voltage or power supply issues
• Communication network issues (e.g., CAN bus problems)

Common misdiagnosis for U1650 U1650: “Module Communication Failure”

• Faulty wiring or connectors
• Defective control module
• Power supply issues
• Grounding problems
• Software glitches or updates needed
• Intermittent communication issues
• Other communication protocol failures
• Sensor malfunctions

Common Troubleshooting Steps

The OBD-II code U1650 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, other codes can provide additional context for the U1650 code.
• 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 a scope, you can check the signal quality on the communication lines.
• Inspect Modules:
• Identify which module is reporting the U1650 code. This may require checking the vehicle’s service manual for module locations and functions.
• If possible, test the module by swapping it with a known good module to see if the problem persists.
• Check for Software Updates: Sometimes, communication issues can be resolved with a software update. Check with the manufacturer for any available updates for the vehicle’s control modules.
• Clear Codes and Test Drive: After performing any repairs or inspections, clear the trouble codes and take the vehicle for a test drive to see if the U1650 code returns.
• Consult Technical Service Bulletins (TSBs): Check for any TSBs related to the U1650 code for your specific vehicle make and model. Manufacturers may have issued guidance on common issues and fixes.
• Professional Diagnosis: If the issue persists after performing the above steps, it may be necessary to consult a professional technician or dealership for further diagnosis. They may have specialized tools and knowledge to address complex communication issues. By following these steps, you can systematically identify and resolve the underlying cause of the U1650 code.