U1969 – Lost Communication with the Body Control Module (BCM).

The ODBII code U1969 indicates that there is a communication failure between the vehicle’s control module and the Body Control Module (BCM), which may affect various electrical functions and systems in the vehicle.

The severity of ODBII code U1969 is generally considered moderate to severe, as it indicates a communication issue that can affect multiple vehicle systems.

Common Causes For: U1967 Lost Communication with the Hybrid Powertrain Control Module (HPCM)”.

• Faulty Body Control Module (BCM)
• Damaged wiring or connectors
• Corroded terminals
• Blown fuses
• Faulty communication network (CAN bus issues)
• Low battery voltage
• Intermittent electrical connections
• Software issues or programming errors

Common misdiagnosis for U1969 Lost Communication with the Body Control Module (BCM)”.

• Faulty Body Control Module (BCM)
• Wiring issues or shorts in the communication lines
• Faulty or corroded connectors
• Issues with the power supply to the BCM
• Faulty Instrument Cluster
• Malfunctioning Engine Control Module (ECM)
• Problems with other control modules in the network
• Software or firmware issues in the BCM
• Battery or charging system problems
• Grounding issues in the vehicle’s electrical system

Common Troubleshooting Steps

When dealing with the OBD-II code U1969, which indicates “Lost Communication with the Body Control Module (BCM),” there are several common troubleshooting steps you can follow to diagnose and potentially resolve the issue. Here’s a structured approach:

• Check for Other Codes: Use an OBD-II scanner to check for any additional trouble codes. Sometimes, other codes can provide context or indicate related issues.
• Inspect the Wiring and Connectors: **Visual Inspection: Check the wiring harness and connectors leading to the BCM for any signs of damage, corrosion, or loose connections.
• **Connector Pins: Ensure that the pins in the connectors are not bent, corroded, or pushed back.
• Check Power and Ground: **Power Supply: Verify that the BCM is receiving the correct voltage. Use a multimeter to check the power supply at the BCM connector.
• **Ground Connections: Ensure that the ground connections for the BCM are secure and free of corrosion.
• Inspect the BCM: **Physical Condition: Check the BCM for any signs of physical damage, such as cracks or burn marks.
• **Reprogramming: If the BCM has been replaced, ensure that it has been properly programmed to the vehicle.
• Test Communication Lines: **CAN Bus: Use a scan tool to check the communication on the CAN bus. If other modules are not communicating, there may be a fault in the bus itself.
• **Scope Testing: If available, use an oscilloscope to check for proper signal patterns on the communication lines.
• Check for Intermittent Issues: **Temperature Sensitivity: Sometimes, issues can be temperature-related. Check if the problem occurs only under certain conditions (e.g., after the vehicle has been running for a while).
• **Vibration: Check if the issue occurs when the vehicle is in motion or over bumps.
• Inspect Related Modules: If the BCM is not communicating, check other modules that may be connected to the same communication network. A fault in one module can affect communication with others.
• Perform a Hard Reset: Disconnect the battery for a few minutes to reset the vehicle’s electronic systems. Reconnect and see if the code reappears.
• Consult Technical Service Bulletins (TSBs): Check for any TSBs related to the BCM or communication issues for your specific vehicle make and model. Manufacturers may have known fixes for common problems.
• Seek Professional Help: If the issue persists after performing the above steps, it may be necessary to consult a professional mechanic or dealership for further diagnosis. They may have specialized tools and knowledge to address complex issues.Conclusion Troubleshooting a U1969 code can be complex, as it often involves multiple systems and components. Following these steps systematically can help identify the root cause of the communication loss with the BCM.