U1854 – Module Communication Failure

The ODBII code U1854 indicates a “Module Communication Failure,” meaning there is a problem with communication between various control modules in the vehicle’s network.

The severity of ODBII code U1854 is moderate.

Common Causes For: U1853 U1853: “Module Communication Failure”

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

Common misdiagnosis for U1854 U1854: “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 module failures in the network

Common Troubleshooting Steps

The OBD-II code U1854 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 communication failure.
• 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 wiring harnesses that connect the modules, as these can be prone to wear and tear.
• Check Power and Ground:
• Ensure that the affected modules are receiving proper power and ground. Use a multimeter to check voltage and ground continuity at the module connectors.
• If there is no power or ground, trace the wiring back to the source to identify any breaks or shorts.
• Test the Modules:
• If possible, test the affected modules individually to ensure they are functioning correctly. This may involve using a scan tool to communicate with the module or swapping it with a known good module.
• Inspect the CAN Bus:
• The communication between modules often occurs over a Controller Area Network (CAN) bus. Check the integrity of the CAN bus wiring and connections.
• Use an oscilloscope or a CAN bus tester to monitor the bus for proper signals and communication.
• Check for Interference:
• Look for any aftermarket devices or modifications that may interfere with the communication between modules. This includes alarms, stereo systems, or other electronic devices.
• Reset the Modules:
• Sometimes, simply resetting the modules can resolve communication issues. Disconnect the battery for a few minutes, then reconnect it and see if the code returns.
• Update Software/Firmware:
• Check if there are any software or firmware updates available for the vehicle’s modules. Sometimes, communication issues can be resolved with an update.
• Consult Technical Service Bulletins (TSBs):
• Look for any TSBs related to the U1854 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, it may be necessary to seek the help of a professional mechanic or dealership with advanced diagnostic tools. By following these steps, you should be able to identify and resolve the underlying cause of the U1854 code.