U1941 – Control Module Communication Fault

The ODBII code U1941 indicates a “Control Module Communication Fault,” meaning there is a problem with communication between control modules in the vehicle, which may affect their ability to share data or function properly.

The severity of ODBII code U1941 is moderate.

Common Causes For: U1940 Lost Communication with the Body Control Module (BCM).

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

Common misdiagnosis for U1941 U1941: “Control Module Communication Fault”

• Faulty control module
• Wiring issues or shorts
• Poor ground connections
• Corroded connectors
• Software glitches or updates needed
• Battery or power supply problems
• Intermittent communication issues
• Faulty sensors or actuators

Common Troubleshooting Steps

The OBD-II code U1941 indicates a “Control Module Communication Fault.” This code typically suggests that there is a communication issue 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, U1941 may be accompanied by other codes that can provide more context about 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 affected modules.
• Check Power and Ground:
• Ensure that the control modules have the proper power supply and ground connections. Use a multimeter to check for voltage and continuity.
• If there are issues with power or ground, repair the wiring as necessary.
• Test Control Modules:
• If possible, test the affected control modules to ensure they are functioning correctly. This may involve using specialized diagnostic tools or swapping with known good modules.
• Check for any software updates or reprogramming requirements for the control modules.
• Inspect the CAN Bus:
• The communication between control modules often occurs over a Controller Area Network (CAN) bus. Inspect the CAN bus wiring for damage or shorts.
• Use a CAN bus scanner to check for communication errors or issues on the bus.
• Check for Interference:
• Look for any aftermarket devices or modifications that may interfere with the communication between control modules. This includes alarm systems, stereo systems, or other electronic devices.
• Clear Codes and Test Drive:
• After performing the above checks and repairs, clear the trouble codes using the OBD-II scanner.
• Take the vehicle for a test drive to see if the code reappears. Monitor the vehicle’s performance and any warning lights.
• Consult Service Manual:
• Refer to the vehicle’s service manual for specific diagnostic procedures related to U1941. This may provide additional insights or steps tailored to your vehicle’s make and model.
• Seek Professional Help:
• If the issue persists after performing the above steps, consider seeking assistance from a qualified mechanic or dealership. They may have access to advanced diagnostic tools and expertise to resolve complex communication issues. By following these troubleshooting steps, you can systematically identify and address the underlying cause of the U1941 code.