U1678 – Invalid Data Received from Vehicle Control Module.

The ODBII code U1678 indicates that the vehicle’s control module has received invalid or corrupted data from another control module, which may affect vehicle performance or functionality.

The severity of ODBII code U1678 is generally considered moderate.

Common Causes For: U1677 Invalid Data Received from Vehicle Control Module.

• Faulty Vehicle Control Module (VCM)
• Poor or damaged wiring/connectors
• Corrupted software or firmware in the VCM
• Communication issues between modules
• Grounding issues
• Interference from aftermarket devices
• Low battery voltage or power supply issues

Common misdiagnosis for U1678 Invalid Data Received from Vehicle Control Module.

• Faulty Vehicle Control Module (VCM)
• Wiring issues or shorts in the communication lines
• Faulty sensors or actuators
• Corrupted software or firmware in the VCM
• Issues with the power supply to the VCM
• Problems with other control modules affecting communication
• Incorrectly installed aftermarket accessories or modifications

Common Troubleshooting Steps

The OBD-II code U1678 indicates that there is invalid data being received from the Vehicle Control Module (VCM). This can be caused by various issues, including communication problems, wiring issues, or faults within the VCM itself. Here are some common troubleshooting steps to help diagnose and resolve the issue:

• Check for Additional Codes: Use an OBD-II scanner to check for any other trouble codes that may be present. This can provide more context and help identify related issues.
• Inspect Wiring and Connectors:
• Visually inspect the wiring and connectors associated with the VCM and any related modules. Look for signs of damage, corrosion, or loose connections.
• Ensure that all connectors are securely plugged in and that there are no bent pins.
• Check for Ground Issues:
• Ensure that the VCM has a good ground connection. A poor ground can lead to communication issues.
• Use a multimeter to check for continuity between the ground point and the VCM.
• Test the VCM:
• If possible, test the VCM to ensure it is functioning correctly. This may involve using a scan tool to monitor data and see if the VCM is sending and receiving data properly.
• If you have access to another vehicle of the same make and model, you can swap the VCM to see if the problem persists.
• Check for Software Updates:
• Sometimes, the issue can be resolved with a software update. Check with the manufacturer or a dealership to see if there are any updates available for the VCM.
• Inspect Related Modules:
• If the VCM communicates with other modules (like the Engine Control Module, Transmission Control Module, etc.), check those modules for faults as well. A problem in one module can affect communication with others.
• Clear Codes and Test Drive:
• 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 Interference:
• Ensure that there are no aftermarket devices or modifications that could be interfering with the vehicle’s communication network.
• Consult Technical Service Bulletins (TSBs):
• Look for any TSBs related to the U1678 code for your specific vehicle make and model. Manufacturers may have issued guidance on common issues and fixes.
• 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 issue causing the U1678 code.