U1930 – Module Communication Failure

The ODBII code U1930 indicates a “Module Communication Failure,” meaning there is a problem with communication between vehicle control modules, often due to a fault in the wiring, connectors, or the modules themselves.

The severity of ODBII code U1930 is moderate.

Common Causes For: U1929 U1929: “Module Communication Failure”

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

Common misdiagnosis for U1930 U1930: “Module Communication Failure”

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

Common Troubleshooting Steps

The OBD-II code U1930 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: Start by scanning the vehicle for any other diagnostic trouble codes (DTCs). Other codes may provide additional context or indicate related issues.
• Inspect Wiring and Connectors:
• Check the wiring harnesses and connectors associated with the affected module for any signs of damage, corrosion, or loose connections.
• Pay special attention to the ground connections, as poor grounding can lead to communication issues.
• Verify Power Supply:
• Ensure that the affected module is receiving the proper voltage and ground. Use a multimeter to check the power and ground circuits.
• If the module is not receiving power, trace the circuit back to the fuse box and check for blown fuses or damaged wiring.
• Check for Module Faults:
• If the module itself is faulty, it may not communicate properly. If possible, test the module in another vehicle or replace it with a known good module to see if the issue persists.
• Inspect the CAN Bus:
• U1930 is often related to issues with the Controller Area Network (CAN) bus. Check for any short circuits, open circuits, or interference on the CAN bus lines.
• Use an oscilloscope or a CAN bus scanner to monitor the communication signals on the bus.
• Look for Software Issues:
• Ensure that the vehicle’s software is up to date. Sometimes, a software update can resolve communication issues between modules.
• If applicable, perform a reset or reprogramming of the affected module.
• Check for Environmental Factors:
• Sometimes, environmental factors such as moisture or extreme temperatures can affect module communication. Inspect for water intrusion or other environmental damage.
• Perform a Network Test:
• If you have access to a professional scan tool, perform a network test to check the communication status of all modules on the bus. This can help identify which module is causing the communication failure.
• Consult Technical Service Bulletins (TSBs):
• Check for any TSBs related to the specific make and model of the vehicle. Manufacturers may have issued guidance on common issues related to U1930.
• Clear Codes and Test Drive:
• After performing the necessary repairs, clear the codes and take the vehicle for a test drive to see if the code returns. If the issue persists after following these steps, it may be necessary to consult a professional technician or a dealership for further diagnosis.