U1885 – Data Bus Communication Failure

The ODBII code U1885 indicates a “Data Bus Communication Failure,” meaning there is a problem with the communication between various electronic control units (ECUs) in the vehicle’s network.

The severity of ODBII code U1885 is moderate.

Common Causes For: U1884 U1884: “Data Bus Communication Failure”

• Faulty wiring or connectors
• Malfunctioning control modules
• Poor ground connections
• Corroded or damaged terminals
• Intermittent electrical connections
• Software issues or bugs in control modules
• Low battery voltage or weak battery
• Faulty or damaged data bus (CAN bus) components
• Aftermarket modifications or installations affecting communication
• Environmental factors (moisture, temperature extremes) affecting connections

Common misdiagnosis for U1885 U1885: “Data Bus Communication Failure”

• Faulty ABS module
• Defective engine control module (ECM)
• Malfunctioning body control module (BCM)
• Wiring issues or shorts
• Bad ground connections
• Faulty sensors
• Communication issues with other modules
• Battery or charging system problems

Common Troubleshooting Steps

The OBD-II code U1885 indicates a “Data Bus Communication Failure.” This code typically points to a problem with the communication between various modules in the vehicle’s network. Here are some common troubleshooting steps to 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. Other codes can provide context and help identify the root cause of the communication failure.
• Inspect the Wiring and Connectors: Visually inspect the wiring harnesses and connectors associated with the affected modules. Look for signs of damage, corrosion, or loose connections.
• Pay special attention to the connectors for the modules that are part of the data bus.
• Test the Modules: Identify which modules are involved in the communication network. Common modules include the Engine Control Module (ECM), Transmission Control Module (TCM), Body Control Module (BCM), and others.
• Check if the affected modules are functioning properly. You may need to perform a module-specific diagnostic test.
• Check the Data Bus: Use a multimeter or an oscilloscope to check the data bus lines (CAN, LIN, etc.) for proper voltage levels and signal integrity.
• Look for short circuits, open circuits, or excessive resistance in the data bus wiring.
• Inspect for Interference: Ensure that there are no aftermarket devices or modifications that could be interfering with the data bus communication.
• Remove any non-factory accessories temporarily to see if the issue resolves.
• Check Power and Ground: Verify that all modules have proper power and ground connections. A weak ground or insufficient power supply can lead to communication failures.
• Perform a Network Test: Some advanced scan tools can perform a network test to check the communication between modules. This can help identify which module is not responding.
• Reset the Codes: After performing checks and repairs, 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 TSBs related to the specific make and model of the vehicle. Manufacturers may have issued guidance on common issues related to data bus communication.
• 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 the specific vehicle and its systems. By following these steps, you should be able to identify and resolve the underlying issue causing the U1885 code.