U1899 – Module Communication Failure

The ODBII code U1899 indicates a “Module Communication Failure,” meaning there is a problem with communication between the vehicle’s control modules, which may affect their ability to share data or function properly.

The severity of ODBII code U1899 is moderate.

Common Causes For: U1898 U1898: “Module Communication Failure”

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

Common misdiagnosis for U1899 U1899: “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 U1899 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, U-codes can be related to other issues that may provide more context.
• 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 ground connections, as poor grounding can lead to communication issues.
• Check Power Supply: Ensure that the affected modules are receiving the proper voltage. Use a multimeter to check the power supply to the modules.
• Test Communication Lines:
• Use a scan tool to check the communication lines (CAN bus, LIN bus, etc.) for continuity and proper voltage levels.
• If you have access to a scope, you can check the signal quality on the communication lines.
• Inspect Modules:
• If possible, check the affected module for any signs of physical damage or water intrusion.
• If you suspect a specific module is faulty, you may consider swapping it with a known good module to see if the problem persists.
• Reset the Modules: Sometimes, simply resetting the modules can resolve communication issues. This can be done by disconnecting the battery for a few minutes or using a scan tool to clear the codes.
• Check for Software Updates: Verify if there are any software updates available for the vehicle’s modules. Sometimes, manufacturers release updates to fix communication issues.
• Look for Intermittent Issues: If the code is intermittent, try to replicate the conditions under which the code appears. This can help identify specific triggers for the communication failure.
• Consult Wiring Diagrams: Refer to the vehicle’s service manual for wiring diagrams and communication protocols to better understand how the modules are supposed to communicate.
• Professional Diagnosis: If the issue persists after performing these steps, it may be necessary to consult a professional technician or dealership for further diagnosis. They may have specialized tools and knowledge to pinpoint the issue. By following these steps, you should be able to identify and potentially resolve the U1899 code.