U1399 – is a manufacturer-specific code that generally indicates a communication issue within the vehicle’s network.
The ODBII code U1399 indicates a communication issue within the vehicle’s network, typically related to a failure in data transmission between modules.
The severity of ODBII code U1399 is generally considered moderate to severe.
Common Causes For: U1398 U1398: “Control Module Communication Failure”
- Faulty wiring or connectors
- Malfunctioning control modules
- Poor ground connections
- Corroded or damaged connectors
- Intermittent electrical issues
- Software glitches in control modules
- Faulty sensors affecting communication
- Issues with the vehicle’s CAN bus system
Common misdiagnosis for U1399 is a manufacturer-specific code that generally indicates a communication issue within the vehicle’s network.
- Faulty wiring or connectors
- Defective control modules
- Incorrectly diagnosed sensor issues
- Battery or charging system problems
- Software or firmware issues
- Grounding problems
- Intermittent electrical faults
- Issues with the vehicle’s CAN bus system
Common Troubleshooting Steps
The OBD-II code U1399 is a manufacturer-specific code that typically indicates a communication issue within the vehicle’s network, often related to the Controller Area Network (CAN) or other communication protocols used by the vehicle’s electronic control units (ECUs). 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 affected modules. Look for signs of damage, corrosion, or loose connections.
- Pay special attention to the CAN bus wiring, as it is critical for communication between modules.
- Check Battery and Ground Connections: Ensure that the vehicle’s battery is in good condition and fully charged.
- Check all ground connections for corrosion or looseness, as poor grounding can lead to communication issues.
- Test the Modules: If you suspect a specific module is causing the issue, test it for proper operation. This may involve checking for power and ground at the module and verifying that it communicates correctly with the scanner.
- Inspect for Short Circuits or Open Circuits: Use a multimeter to check for short circuits or open circuits in the wiring harnesses related to the communication network.
- Check for Software Updates: Some manufacturers release software updates for their ECUs. Check if there are any available updates that may address communication issues.
- Clear Codes and Test Drive: After performing any repairs or inspections, clear the trouble codes using the OBD-II scanner and take the vehicle for a test drive to see if the code returns.
- Consult Manufacturer Documentation: Refer to the vehicle’s service manual or manufacturer-specific documentation for any additional troubleshooting steps or specific procedures related to the U1399 code.
- Professional Diagnosis: If the issue persists after performing the above steps, consider seeking help from a professional mechanic or dealership with experience in diagnosing communication issues in your specific vehicle make and model.
- Check for Environmental Factors: Sometimes, environmental factors such as moisture or extreme temperatures can affect the vehicle’s electrical systems. Ensure that the vehicle is in a suitable environment for testing. By following these steps, you can systematically diagnose and potentially resolve the communication issue indicated by the U1399 code.