U1988 – Lost Communication with the Body Control Module (BCM).

The ODBII code U1988 indicates that there is a communication failure between the vehicle’s control module and the Body Control Module (BCM), which may affect various electrical systems and functions.

The severity of ODBII code U1988 is generally considered moderate to severe.

Common Causes For: U1987 U1987: “Module Communication Failure”

• Faulty Body Control Module (BCM)
• Damaged wiring or connectors
• Corroded terminals
• Blown fuses
• Poor ground connections
• Malfunctioning communication network (CAN bus)
• Software issues or programming errors
• Other module failures affecting communication

Common misdiagnosis for U1988 Lost Communication with the Body Control Module (BCM)”.

• Faulty Body Control Module (BCM)
• Wiring issues or damaged connectors
• Faulty or corroded ground connections
• Issues with the power supply to the BCM
• Faulty communication lines (CAN bus issues)
• Other module failures (e.g., PCM, ABS module)
• Software or firmware issues in the BCM
• Battery or charging system problems
• Faulty ignition switch
• Intermittent electrical connections

Common Troubleshooting Steps

When dealing with the OBD-II code U1988, 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, multiple codes can provide more context about 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 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, test the BCM for functionality. This may involve using specialized diagnostic equipment or swapping it with a known good unit.
• 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 open circuits in the wiring that connects the BCM to the rest of the vehicle’s network.
• Look for Software Issues: Sometimes, a software update may be required for the BCM or other modules. Check with the manufacturer for any available updates.
• Reset the System: Disconnect the battery for a few minutes to reset the vehicle’s computer systems. Reconnect and see if the code reappears.
• Scan for Communication Protocol Issues: Use a scan tool to check if the BCM is communicating with the vehicle’s network. If it’s not, there may be a problem with the CAN bus or other communication lines.
• Consult Technical Service Bulletins (TSBs): Check for any TSBs related to the U1988 code for your specific vehicle make and model. Manufacturers may have specific fixes or recommendations.1
• Professional Diagnosis: If the issue persists after performing the above steps, consider seeking help from a professional mechanic or dealership with experience in diagnosing BCM-related issues.Conclusion Troubleshooting a U1988 code can be complex, as it may involve multiple systems and components. Following these steps systematically can help identify the root cause of the communication loss with the BCM. Always refer to the vehicle’s service manual for specific procedures and specifications.