U2964 – Lost Communication with the Body Control Module (BCM) – Bus Off.

The ODBII code U2964 indicates that there is a loss of communication with the Body Control Module (BCM) due to the module being in a “Bus Off” state, which typically means it is unable to communicate on the vehicle’s network due to a fault or error condition.

The severity of ODBII code U2964 is generally considered moderate to high.

Common Causes For: U2963 Lost Communication with the Hybrid Powertrain Control Module (HPCM) A.

• Faulty Body Control Module (BCM)
• Damaged wiring or connectors in the communication circuit
• Short circuit or open circuit in the CAN bus
• Faulty or corroded ground connections
• Malfunctioning or damaged CAN bus transceiver
• Issues with other modules on the CAN bus
• Software or firmware issues in the BCM
• Low battery voltage or power supply issues

Common misdiagnosis for U2964 Lost Communication with the Body Control Module (BCM) – Bus Off.

• Faulty Body Control Module (BCM)
• Wiring issues or damaged connectors
• Faulty communication network (CAN bus)
• Power supply issues to the BCM
• Faulty or corroded ground connections
• Other module failures affecting communication
• Software or firmware issues in the BCM
• Battery or charging system problems

Common Troubleshooting Steps

When dealing with the OBD-II code U2964, which indicates “Lost Communication with the Body Control Module (BCM) – Bus Off,” there are several common troubleshooting steps you can follow to diagnose and potentially resolve the issue. Here’s a structured approach:

• Check for Additional Codes: Use an OBD-II scanner to check for any other diagnostic trouble codes (DTCs) that may be present. This can provide additional context for the issue.
• Inspect the Wiring and Connectors: **Visual Inspection: Check the wiring harness and connectors related to the BCM for any signs of damage, corrosion, or loose connections.
• **Connector Pins: Ensure that the pins in the connectors are not bent or corroded.
• Check the BCM: **Power and Ground: Verify that the BCM is receiving proper power and ground. Use a multimeter to check voltage at the BCM connector.
• **Module Functionality: If possible, test the BCM in another vehicle or replace it with a known good unit to see if the problem persists.
• Inspect the CAN Bus: **Bus Integrity: Check the integrity of the CAN bus wiring. Look for shorts, opens, or high resistance in the bus lines.
• **Termination Resistors: Ensure that the CAN bus has the correct termination resistors (typically 120 ohms) at both ends of the bus.
• Check for Interference: **Other Modules: Inspect other modules on the CAN bus for faults. A malfunctioning module can cause communication issues.
• **Electrical Interference: Look for sources of electrical interference that may affect communication.
• Scan Tool Communication: **Communication Test: Use a scan tool to check if you can communicate with the BCM. If you cannot, it may indicate a problem with the BCM or the communication lines.
• **Data Stream: Review the data stream from the BCM to see if it is responding correctly.
• Reset the System: **Clear Codes: Clear the DTCs using the scan tool and see if the code returns after a test drive.
• **Battery Disconnect: Disconnect the battery for a few minutes to reset the system, then reconnect and check for codes again.
• Check for Software Updates: **Manufacturer Updates: Check if there are any software updates available for the BCM or other related modules that may address communication issues.
• Consult Technical Service Bulletins (TSBs): Look for any TSBs related to the specific make and model of the vehicle that may provide guidance on known issues with the BCM or communication problems.
• Professional Diagnosis: If the issue persists after performing the above steps, consider seeking help from a professional technician or dealership with experience in diagnosing BCM and communication issues. By following these steps, you should be able to identify the root cause of the U2964 code and take appropriate action to resolve the communication issue with the Body Control Module.