U1317 – CAN Communication Bus Off.

The ODBII code U1317 indicates a communication issue where the Controller Area Network (CAN) bus is offline or not functioning properly, affecting communication between modules in the vehicle.

The severity of ODBII code U1317 CAN Communication Bus Off is moderate to severe.

Common Causes For: U1316 Lost Communication with Body Control Module (BCM)”.

• Faulty CAN bus wiring or connectors
• Defective CAN bus module
• Short circuit in the CAN bus
• Open circuit in the CAN bus
• Poor ground connection
• Interference from other electronic devices
• Faulty or incompatible aftermarket accessories
• Software or firmware issues in the control modules
• Low battery voltage or power supply issues
• Corroded or damaged terminals

Common misdiagnosis for U1317 CAN Communication Bus Off.

• Faulty Engine Control Module (ECM)
• Bad Transmission Control Module (TCM)
• Defective Body Control Module (BCM)
• Wiring issues or shorts in the CAN bus
• Faulty sensors or actuators
• Battery or charging system problems
• Poor ground connections
• Corrupted software or firmware in modules

Common Troubleshooting Steps

The OBD-II code U1317 indicates a problem with the CAN (Controller Area Network) communication bus, specifically that one of the modules on the bus has gone “off.” This can lead to communication issues between various electronic control units (ECUs) in the vehicle. Here are some common troubleshooting steps to diagnose and resolve the U1317 code:

• Check for Additional Codes: Use an OBD-II scanner to check for any other trouble codes that may be present. Other codes can provide context and help identify the root cause of the issue.
• Inspect the Wiring and Connectors: Visually inspect the wiring harnesses and connectors associated with the CAN bus. Look for signs of damage, corrosion, or loose connections.
• Pay special attention to the connectors on the ECUs, as these can often be a source of communication issues.
• Test the CAN Bus Voltage: Use a multimeter to check the voltage levels on the CAN bus wires (typically CAN High and CAN Low). The voltage should be around 2.5V when the bus is idle.
• If the voltage levels are outside the expected range, there may be a short circuit or an open circuit in the wiring.
• Check for Short Circuits or Open Circuits: Use a multimeter to check for continuity in the CAN bus wiring. Look for any shorts to ground or power, as well as any breaks in the wiring.
• Inspect the ECUs: Identify which ECU is causing the issue. This may require disconnecting each ECU one at a time and checking for the code to clear.
• If a specific ECU is identified as the problem, inspect it for damage or failure. In some cases, reprogramming or replacing the ECU may be necessary.
• Check for Interference: Ensure that there are no aftermarket devices or modifications that could be interfering with the CAN bus communication. This includes things like alarm systems, stereo systems, or other electronic accessories.
• Perform a Network Test: If available, use a professional scan tool to perform a network test. This can help identify which module is not communicating properly.
• Clear the 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 U1317 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 CAN bus systems and can perform more advanced diagnostics. By following these steps, you should be able to identify and resolve the issue causing the U1317 code.