U2772 – Vehicle Communication Bus Malfunction

The ODBII code U2772 indicates a malfunction in the vehicle communication bus, which affects the communication between various control modules in the vehicle.

The severity of ODBII code U2772 is moderate.

Common Causes For: U2771 U2771: Vehicle Communication Bus Malfunction

• Faulty OBD-II connector
• Damaged wiring or connectors in the communication bus
• Malfunctioning control modules
• Poor ground connections
• Interference from aftermarket devices
• Software issues or bugs in the control modules
• Low battery voltage or weak battery
• Corroded terminals or connectors
• Faulty or incompatible diagnostic tools
• Issues with the vehicle’s CAN bus system

Common misdiagnosis for U2772 Vehicle Communication Bus Malfunction

• Faulty ECM (Engine Control Module)
• Bad wiring or connectors
• Defective sensors
• Issues with the CAN bus system
• Power supply problems
• Faulty body control module (BCM)
• Incorrectly programmed modules
• Software glitches or updates needed
• Grounding issues
• Other communication-related codes misinterpretation

Common Troubleshooting Steps

The OBD-II code U2772 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:
• Visually inspect the wiring and connectors associated with the communication bus (CAN bus). Look for signs of damage, corrosion, or loose connections.
• Pay special attention to the connectors on the modules that are part of the communication network.
• Check for Short Circuits:
• Use a multimeter to check for short circuits in the wiring. This includes checking for continuity between the communication wires and ground or power.
• Test the Modules:
• If you suspect a specific module is causing the issue, you can test it by disconnecting it and checking if the code persists. If the code goes away, the module may be faulty.
• Ensure that all modules are properly powered and grounded.
• Inspect the CAN Bus:
• Use an oscilloscope or a CAN bus analyzer to check the signal integrity on the CAN bus. Look for any irregularities in the signal that could indicate a problem.
• Check the termination resistors (typically 120 ohms) at both ends of the CAN bus. If they are missing or faulty, it can cause communication issues.
• Check for Interference:
• Look for any aftermarket devices or modifications that may interfere with the vehicle’s communication systems. This includes alarms, stereo systems, or other electronic devices.
• Update Software/Firmware:
• Check if there are any software updates available for the vehicle’s modules. Sometimes, manufacturers release updates to fix communication issues.
• Clear Codes and Test Drive:
• After performing the above 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 U2772 code for your specific vehicle make and model. Manufacturers may have specific recommendations or known issues that can help in troubleshooting.
• Seek Professional Help:
• If the issue persists after performing these steps, it may be necessary to consult a professional mechanic or technician who has experience with vehicle communication systems. By following these steps, you should be able to identify and resolve the underlying issue causing the U2772 code.