U1260 – Communication Bus Fault.

The ODBII code U1260 indicates a communication bus fault, meaning there is a problem with the data exchange between the vehicle’s control modules, often due to a wiring issue, a faulty module, or a disruption in the communication network.

The severity of ODBII code U1260 Communication Bus Fault is moderate.

Common Causes For: U1259 Lost Communication with Fuel Pump Control Module.

• Faulty wiring or connectors in the communication bus.
• Malfunctioning control modules.
• Corroded or damaged terminals.
• Short circuits in the communication lines.
• Open circuits in the communication lines.
• Interference from aftermarket devices.
• Software issues or bugs in the control modules.

Common misdiagnosis for U1260 Communication Bus Fault.

• Faulty Engine Control Module (ECM)
• Bad Wiring or Connectors
• Defective Body Control Module (BCM)
• Malfunctioning Transmission Control Module (TCM)
• Issues with the Powertrain Control Module (PCM)
• Faulty Sensors (e.g., ABS, airbag)
• Battery or Charging System Problems
• Grounding Issues
• Faulty Communication Network (CAN bus) Components
• Software or Firmware Issues

Common Troubleshooting Steps

The OBD-II code U1260 indicates a “Communication Bus Fault,” which typically means there is a problem with the communication between the vehicle’s control modules. 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 related to the communication bus (CAN bus). Look for signs of damage, corrosion, or loose connections.
• Pay special attention to the connectors on the Engine Control Module (ECM), Body Control Module (BCM), and any other modules that communicate over the bus.
• Check for Short Circuits:
• Use a multimeter to check for short circuits in the communication lines. Measure resistance between the CAN high and CAN low wires; they should not be shorted together.
• Test the Modules:
• If possible, test the individual control modules for proper operation. A faulty module can disrupt communication on the bus.
• You may need to use a scan tool that can communicate with each module to check for any issues.
• Inspect the CAN Bus Termination:
• Ensure that the CAN bus has proper termination resistors (typically 120 ohms) at both ends of the bus. If these resistors are missing or damaged, it can cause communication issues.
• Check for Interference:
• Look for any aftermarket devices or modifications that may interfere with the communication bus. This includes alarm systems, stereo systems, or other electronic devices.
• Battery and Ground Connections:
• Check the vehicle’s battery and ground connections. A weak battery or poor ground can cause communication issues.
• Perform a Network Test:
• If you have access to advanced diagnostic tools, perform a network test to check the integrity of the communication bus.
• 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 for your make and model. 1
• Seek Professional Help:
• If the issue persists after performing these steps, it may be necessary to consult a professional mechanic or dealership for further diagnosis. By following these steps, you should be able to identify and resolve the underlying issue causing the U1260 code.