U1616 – Lost Communication with Body Control Module (BCM).

The ODBII code U1616 indicates a loss of communication between the vehicle’s control module and the Body Control Module (BCM), which can affect various electrical systems and functions in the vehicle.

The severity of ODBII code U1616 is generally considered moderate to severe.

Common Causes For: U1615 refers to a communication issue between the Engine Control Module (ECM) and the Transmission Control Module (TCM).

• Faulty Body Control Module (BCM)
• Damaged or corroded wiring or connectors
• Poor ground connection
• Faulty communication network (CAN bus issues)
• Blown fuses
• Software or firmware issues in the BCM
• Intermittent electrical connections
• Other module failures affecting communication

Common misdiagnosis for U1616 Lost Communication with 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
• Malfunctioning other control modules
• Software or firmware issues in the BCM
• Faulty ignition switch
• Battery or charging system problems

Common Troubleshooting Steps

When dealing with the OBD-II code U1616, which indicates “Lost Communication with 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 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 Power and Ground: **Power Supply: Verify that the BCM is receiving the correct voltage. Use a multimeter to check the power supply to the BCM.
• **Ground Connections: Ensure that the ground connections for the BCM are secure and free of corrosion.
• Test the BCM: If possible, perform a functional test of the BCM. Some diagnostic tools can communicate with the BCM to check its status and functionality.
• If the BCM is not responding, it may need to be replaced.
• Inspect Related Modules: Check for communication issues with other modules in the vehicle. If other modules are also having communication problems, it may indicate a network issue rather than a BCM-specific problem.
• Check for Short Circuits or Open Circuits: Use a multimeter to check for shorts or opens in the wiring harness that connects to the BCM. This includes checking for continuity in the communication lines (CAN bus).
• Look for Environmental Factors: Ensure that there are no environmental factors affecting the BCM, such as water intrusion or excessive heat.
• Reset the System: Clear the trouble codes using an OBD-II scanner and see if the code returns. Sometimes, a temporary glitch can cause communication issues.
• Software Updates: Check if there are any software updates available for the BCM or the vehicle’s ECU. Sometimes, manufacturers release updates to fix communication issues.
• Consult Technical Service Bulletins (TSBs): Look for any TSBs related to the U1616 code for your specific vehicle make and model. Manufacturers may have specific recommendations or known issues.1
• Professional Diagnosis: If the issue persists after performing the above steps, consider seeking help from a professional mechanic or dealership. They may have specialized tools and knowledge to diagnose complex communication issues.Conclusion Troubleshooting a U1616 code can involve a combination of electrical diagnostics, visual inspections, and possibly module replacement. Always ensure safety precautions are taken when working with vehicle electronics.