U1264 – Communication Bus Off.

The ODBII code U1264 indicates a communication issue where the vehicle’s communication bus is offline or not functioning properly, often due to a fault in the network or a module.

The severity of ODBII code U1264 Communication Bus Off is moderate to severe.

Common Causes For: U1263 Communication Bus Off.

• Faulty wiring or connectors in the communication bus.
• Malfunctioning control modules.
• Short circuits or open circuits in the communication lines.
• Corroded or damaged connectors.
• Power supply issues to the control modules.
• Software or firmware issues in the control modules.
• Interference from aftermarket devices or modifications.

Common misdiagnosis for U1264 Communication Bus Off.

• Faulty Engine Control Module (ECM)
• Bad Wiring or Connectors
• Defective Sensor
• Powertrain Control Module (PCM) Issues
• Battery or Charging System Problems
• Faulty Body Control Module (BCM)
• Incorrectly Installed Aftermarket Accessories
• Communication Network Issues (e.g., CAN bus problems)

Common Troubleshooting Steps

The OBD-II code U1264 indicates a “Communication Bus Off” condition, which typically means that there is a problem with the communication between the vehicle’s control modules. This can be caused by various issues, including wiring problems, module failures, or issues with the communication bus itself. Here are some common troubleshooting steps to diagnose and resolve the U1264 code:

• Check for Additional Codes: Use an OBD-II scanner to check for any other trouble codes that may be present. This can provide more context about the issue.
• Inspect Wiring and Connectors:
• Visually inspect the wiring and connectors related to the communication bus (CAN bus, LIN bus, etc.) for any signs of damage, corrosion, or loose connections.
• Pay special attention to the connectors at the control modules and any junction points.
• Test the Communication Bus:
• Use a multimeter or an oscilloscope to check the voltage levels and signal integrity on the communication bus wires.
• Ensure that the bus is receiving the correct voltage and that the signals are within the expected range.
• Check for Short Circuits or Open Circuits:
• Use a multimeter to check for short circuits between the communication bus wires and ground or power.
• Check for open circuits that may prevent communication between modules.
• Inspect Control Modules:
• Identify the control modules that are part of the communication network and check for any signs of failure or damage.
• If possible, perform a reset or reprogramming of the affected modules.
• Look for Ground Issues:
• Ensure that all ground connections related to the control modules and communication bus are secure and free of corrosion.
• Check for Interference:
• Look for any aftermarket devices or modifications that may be interfering with the communication bus, such as alarms, remote starters, or other electronic devices.
• Perform a Network Test:
• If available, use a scan tool that can perform a network test to check the status of each module on the bus and identify any that are not responding.
• Clear Codes and Test Drive:
• After performing the above checks and repairs, clear the trouble codes and take the vehicle for a test drive to see if the code returns.
• Consult Service Manual:
• Refer to the vehicle’s service manual for specific diagnostic procedures related to the communication bus and the U1264 code. 1
• 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 automotive electronics and communication systems. By following these troubleshooting steps, you should be able to identify and resolve the underlying issue causing the U1264 code.