U1919 – Module Communication Failure

The ODBII code U1919 indicates a “Module Communication Failure,” meaning there is a problem with communication between the vehicle’s control modules, which may affect their ability to exchange data properly.

The severity of ODBII code U1919 is moderate.

Common Causes For: U1918 U1918: “Module Communication Failure”

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

Common misdiagnosis for U1919 U1919: “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 U1919 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, multiple codes can provide more context for the issue.
• Inspect Wiring and Connectors:
• Visually inspect the wiring and connectors associated with the affected module(s). 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 affected module has a proper power supply and ground connection. Use a multimeter to check for voltage at the module’s power and ground pins.
• If there is no power or ground, trace the wiring back to the source to identify any breaks or shorts.
• Test the Module:
• If possible, test the affected module to ensure it is functioning correctly. This may involve bench testing or swapping with a known good module.
• If the module is not responding, it may need to be repaired or replaced.
• Check for Communication:
• Use a scan tool to check if the affected module is communicating with other modules. If it is not, there may be a communication issue.
• You can also use a scope or a scan tool with live data capabilities to monitor communication signals.
• Inspect the CAN Bus:
• If the vehicle uses a Controller Area Network (CAN) bus, check for issues with the bus itself. Look for short circuits, open circuits, or interference.
• Use a CAN bus analyzer if available to monitor the data traffic on the bus.
• Reset the Codes:
• After performing any repairs or adjustments, 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):
• Check for any manufacturer-specific TSBs related to U1919 or module communication issues. There may be known fixes or recalls that apply to your vehicle.
• Seek Professional Help:
• If the issue persists after performing the above steps, it may be necessary to consult a professional mechanic or technician who has experience with your specific vehicle make and model. By following these troubleshooting steps, you can systematically identify and resolve the underlying cause of the U1919 code.