U2620 – refers to a communication issue related to the Vehicle Communication Bus.

The ODBII code U2620 indicates a communication issue related to the Vehicle Communication Bus, specifically indicating a problem with the communication between modules on the vehicle’s network.

The severity of ODBII code U2620 is generally considered moderate to severe, as it indicates a communication issue that can affect multiple systems in the vehicle.

Common Causes For: U2619 U2619: “CAN Bus Communication Failure”

• Faulty wiring or connectors in the communication bus.
• Malfunctioning control modules.
• Corroded or damaged terminals.
• Interference from aftermarket devices.
• Poor ground connections.
• Software issues or bugs in the control modules.
• Low battery voltage or power supply issues.

Common misdiagnosis for U2620 refers to a communication issue related to the “Vehicle Communication Bus.

• Faulty ECU (Engine Control Unit)
• Bad wiring or connectors
• Defective sensors
• Malfunctioning body control module (BCM)
• Issues with the transmission control module (TCM)
• Battery or power supply problems
• Software glitches or outdated firmware
• Faulty diagnostic tool or scanner
• Intermittent electrical issues
• Grounding problems

Common Troubleshooting Steps

The OBD-II code U2620 indicates a communication issue related to the “Vehicle Communication Bus.” This code typically points to a problem with the communication between various modules in the vehicle, often related to the CAN (Controller Area Network) bus system. Here are some common troubleshooting steps to diagnose and resolve the issue:

• Check for Other Codes: Use an OBD-II scanner to check for any additional trouble codes. Other codes may provide more context or indicate which module is having communication issues.
• Inspect Wiring and Connectors:
• Visually inspect the wiring and connectors associated with the communication 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 harness. A short can disrupt communication between modules.
• 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.
• Reconnect the module and check for proper operation.
• Inspect the CAN Bus:
• Use a CAN bus diagnostic tool to monitor the bus for errors. This can help identify if there are issues with the bus itself or if a specific module is not communicating properly.
• Check the termination resistors at both ends of the CAN bus. If they are missing or faulty, it can cause communication issues.
• Check Power and Ground:
• Ensure that all modules on the communication bus have proper power and ground connections. A lack of power or a poor ground can prevent modules from communicating.
• Look for Interference:
• Check for any aftermarket devices or modifications that may interfere with the communication bus. This includes alarms, stereo systems, or other electronic devices.
• Update Software/Firmware:
• In some cases, updating the software or firmware of the affected modules may resolve communication issues. Check with the manufacturer for any available updates.
• Perform a Network Test:
• Some advanced scan tools can perform a network test to check the integrity of the communication bus. This can help identify issues that are not immediately visible.
• 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 communication issues. 1
• 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 address complex communication issues. By following these steps, you can systematically identify and resolve the underlying cause of the U2620 code.