U2773 – Vehicle Communication Bus Malfunction

The ODBII code U2773 indicates a malfunction in the vehicle communication bus, which affects the communication between various control modules in the vehicle.

The severity of ODBII code U2773 is moderate.

Common Causes For: U2772 Vehicle Communication Bus Malfunction

• Faulty wiring or connectors in the communication bus
• Malfunctioning control modules
• Corrupted software or firmware in control modules
• Poor ground connections
• Short circuits or open circuits in the communication lines
• Interference from aftermarket devices
• Damaged or defective OBD-II port
• Low battery voltage or power supply issues

Common misdiagnosis for U2773 U2773: Vehicle Communication Bus Malfunction

• Faulty OBDII connector
• Defective ECM (Engine Control Module)
• Malfunctioning BCM (Body Control Module)
• Wiring issues or shorts in the communication lines
• Faulty sensors or actuators
• Software glitches or outdated firmware
• Battery or power supply issues
• Corroded or loose connectors
• Interference from aftermarket devices or modifications
• Issues with the CAN bus system

Common Troubleshooting Steps

The OBD-II code U2773 indicates a “Vehicle Communication Bus Malfunction.” This code typically points to issues with the communication between various modules in the vehicle, which can affect the overall functionality of the vehicle’s systems. Here are some common troubleshooting steps to diagnose and resolve this issue:

• Check for Additional 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: **Visual Inspection: Check the wiring and connectors related to the communication bus (CAN bus) for any signs of damage, corrosion, or loose connections.
• **Repair or Replace: If any damaged wires or connectors are found, repair or replace them as necessary.
• Check for Short Circuits: Use a multimeter to check for short circuits in the communication lines. Ensure that there are no unintended connections between the communication wires and ground or power.
• Test the Modules: **Module Functionality: Verify that all modules on the communication bus are functioning correctly. This may involve checking each module for fault codes and ensuring they are communicating properly.
• **Reprogram or Reset: If a specific module is found to be malfunctioning, it may need to be reprogrammed or reset.
• Inspect the CAN Bus: **Termination Resistors: Check the termination resistors at both ends of the CAN bus. Ensure they are present and functioning correctly.
• **Bus Voltage: Measure the voltage on the CAN bus to ensure it is within the expected range (typically around 2.5V when idle).
• Check for Interference: Look for any aftermarket devices or modifications that may be interfering with the communication bus. This includes alarms, stereo systems, or other electronic devices.
• Battery and Ground Connections: Ensure that the vehicle’s battery is in good condition and that all ground connections are secure. Poor battery voltage or ground issues can lead to communication problems.
• Perform a System Reset: Disconnect the battery for a few minutes to reset the vehicle’s computer systems. Reconnect and see if the code reappears.
• Consult Technical Service Bulletins (TSBs): Check for any manufacturer-specific TSBs related to the U2773 code. There may be known issues or recalls that could provide guidance.
• Professional Diagnosis: If the issue persists after performing the above steps, consider seeking help from a professional mechanic or dealership. They may have specialized diagnostic tools and experience with your specific vehicle make and model.Conclusion Troubleshooting a U2773 code can be complex due to the nature of vehicle communication systems. Following these steps systematically can help identify and resolve the underlying issue. Always refer to the vehicle’s service manual for specific procedures and specifications related to your vehicle.