U2047 – Control Module Communication Bus Fault

The ODBII code U2047: Control Module Communication Bus Fault indicates a communication issue between control modules in the vehicle, suggesting that one or more modules are not able to communicate properly over the vehicle’s data bus.

The severity of ODBII code U2047 is moderate.

Common Causes For: U2046 Control Module Communication Bus Off.

• Faulty control module
• Damaged wiring or connectors
• Poor ground connections
• Corroded terminals
• Short circuits in the communication bus
• Intermittent electrical connections
• Software issues or bugs in the control module
• Faulty or incompatible aftermarket parts
• Low battery voltage or power supply issues
• Communication network issues (e.g., CAN bus problems)

Common misdiagnosis for U2047 U2047: Control Module Communication Bus Fault

• Faulty control module
• Wiring issues
• Poor ground connections
• Corroded connectors
• Software glitches
• Battery or power supply problems
• Intermittent communication issues
• Faulty sensors

Common Troubleshooting Steps

The OBD-II code U2047 indicates a “Control Module Communication Bus Fault.” This code typically means that there is a communication issue between the control modules in the vehicle. 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 associated with the control modules. Look for signs of damage, corrosion, or loose connections.
• Pay special attention to the communication bus wires (CAN bus) and ensure they are not pinched or shorted.
• Check Power and Ground: Verify that the control modules have proper power and ground connections. Use a multimeter to check voltage and ground continuity.
• Ensure that the battery is in good condition and fully charged.
• Test the Communication Bus: Use a scan tool to monitor the communication on the CAN bus. Check for proper data transmission between modules.
• If possible, use an oscilloscope to analyze the signal on the communication lines for any irregularities.
• Inspect Control Modules: If a specific control module is suspected to be faulty, consider testing or replacing it. This may involve swapping it with a known good module if available.
• Ensure that the control modules are properly programmed and configured for the vehicle.
• Check for Intermittent Issues: Sometimes, communication faults can be intermittent. Pay attention to when the code appears (e.g., during specific driving conditions or after certain events).
• Consider performing a wiggle test on the wiring harnesses while monitoring for changes in the code.
• Clear Codes and Test Drive: After performing inspections and repairs, clear the trouble codes using the OBD-II scanner.
• Take the vehicle for a test drive to see if the code returns. Monitor the vehicle’s performance and any warning lights.
• Consult Technical Service Bulletins (TSBs): Check for any manufacturer-specific TSBs related to U2047 or communication issues. There may be known fixes or recalls for your vehicle model.
• Seek Professional Help: If the issue persists after performing the above steps, it may be necessary to consult a professional mechanic or technician with experience in automotive electronics and diagnostics. By following these troubleshooting steps, you can systematically identify and resolve the underlying cause of the U2047 code.