U1918 – Module Communication Failure

The ODBII code U1918 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 U1918 is moderate.

Common Causes For: U1917 U1917: “Module Communication Failure”

• Faulty wiring or connectors
• Failed control module
• Corrupted software or firmware
• Poor ground connections
• Intermittent electrical issues
• Communication network issues (e.g., CAN bus problems)
• Low battery voltage or power supply issues
• Damaged or shorted circuits

Common misdiagnosis for U1918 U1918: “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
• Sensor malfunctions

Common Troubleshooting Steps

The OBD-II code U1918 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 to the module that is reporting the U1918 code.
• Check Power and Ground:
• Ensure that the affected module is receiving proper power and ground. Use a multimeter to check voltage and ground continuity.
• If the module is not receiving power, trace the wiring back to the fuse box and check for blown fuses or damaged wiring.
• Test the Module:
• If possible, test the affected module to ensure it is functioning correctly. This may involve using specialized diagnostic tools or swapping the module with a known good one.
• If the module is faulty, it may need to be repaired or replaced.
• Check for Communication Issues:
• Use a scan tool to check if other modules in the network are communicating properly. If other modules are also reporting communication issues, it may indicate a problem with the communication bus (CAN bus).
• Inspect the CAN bus wiring for damage or shorts.
• Reset the Codes:
• After performing any repairs or inspections, clear the trouble codes using the OBD-II scanner and take the vehicle for a test drive to see if the code returns.
• Check for Software Updates:
• In some cases, a software update may be available for the vehicle’s modules. Check with the manufacturer or a dealership to see if any updates are needed.
• Consult Technical Service Bulletins (TSBs):
• Look for any TSBs related to the U1918 code for your specific vehicle make and model. Manufacturers may have specific recommendations or known issues that can help in troubleshooting.
• Professional Diagnosis:
• If the issue persists after performing the above steps, consider seeking help from a professional mechanic or dealership with experience in diagnosing module communication issues. By following these steps, you should be able to identify and resolve the underlying cause of the U1918 code.