U2812 – Module Communication Failure

The ODBII code U2812 indicates a “Module Communication Failure,” meaning there is a problem with communication between vehicle control modules, which may affect their ability to exchange data properly.

The severity of ODBII code U2812 is moderate.

Common Causes For: U2811 Lost Communication with the Hybrid Powertrain Control Module (HPCM)”.

• Faulty wiring or connectors
• Failed control module
• Poor ground connections
• Corroded terminals
• Intermittent communication issues
• Software or firmware issues
• Low battery voltage
• Electrical interference
• Damaged or shorted circuits
• Incompatible modules

Common misdiagnosis for U2812 U2812: “Module Communication Failure”

• Faulty wiring or connectors
• Defective control module
• Software issues or updates needed
• Battery or power supply problems
• Grounding issues
• Intermittent communication issues
• Other communication protocol failures

Common Troubleshooting Steps

The OBD-II code U2812 indicates a “Module Communication Failure,” which typically means that there is a problem with communication between the vehicle’s control modules. Here are some common troubleshooting steps to diagnose and resolve this issue:

• Check for Other 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 affected modules. Look for signs of damage, corrosion, or loose connections.
• Pay special attention to the ground connections, as poor grounding can lead to communication issues.
• Check Power Supply:
• Ensure that the affected modules are receiving the proper voltage. Use a multimeter to check the power supply to the modules.
• Verify that the fuses related to the communication network are intact.
• Test Communication Lines:
• Use a scan tool to check the communication lines (CAN bus, LIN bus, etc.) for continuity and proper voltage levels.
• If you have access to an oscilloscope, you can check the signal waveforms on the communication lines to ensure they are functioning correctly.
• Inspect Modules:
• If possible, check the affected module for any signs of physical damage or water intrusion.
• If you suspect a specific module is faulty, you may consider swapping it with a known good module to see if the issue persists.
• Reset Modules:
• Sometimes, resetting the modules can resolve communication issues. Disconnect the battery for a few minutes, then reconnect it and see if the code returns.
• Check for Software Updates:
• Verify if there are any software updates available for the vehicle’s control modules. Sometimes, manufacturers release updates to fix communication issues.
• Scan Tool Communication:
• Ensure that your scan tool is compatible with the vehicle and can communicate with all modules. Some vehicles may require specific tools for certain modules.
• Look for Intermittent Issues:
• If the code is intermittent, try to replicate the conditions under which the code appears. This can help identify specific triggers for the communication failure.
• Consult Technical Service Bulletins (TSBs):
• Check for any TSBs related to the specific make and model of the vehicle. Manufacturers may have documented known issues and solutions for communication failures. 1
• Professional Diagnosis:
• If the issue persists after performing the above steps, it may be necessary to consult a professional technician or dealership for further diagnosis. They may have specialized tools and knowledge to address complex communication issues. By following these steps, you can systematically diagnose and potentially resolve the U2812 code.