U1983 – Lost Communication with the Body Control Module (BCM).

The ODBII code U1983 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 U1983 is generally considered moderate to severe, as it indicates a communication issue that can affect multiple vehicle systems.

Common Causes For: U1982 U1982: “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 U1983 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
• Problems with 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 U1983, 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 Additional Codes: Use an OBD-II scanner to check for any other trouble codes that may be present. This can provide more context and help identify related issues.
• Inspect 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 or water intrusion.
• **Reprogramming: If the BCM has been replaced, it may need to be reprogrammed 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 Short Circuits: Inspect the wiring for any short circuits to ground or power that could affect communication with the BCM.
• Look for Environmental Factors: Consider if there are any environmental factors (like moisture or extreme temperatures) that could be affecting the BCM or its connections.
• 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 manufacturer-specific TSBs related to the BCM or communication issues that may provide additional guidance.
• Replace the BCM (if necessary): If all other troubleshooting steps fail and the BCM is determined to be faulty, consider replacing it. Ensure proper programming and configuration after replacement.1
• Seek Professional Help: If you are unable to resolve the issue, it may be best to consult a professional mechanic or dealership with experience in diagnosing BCM-related issues.Conclusion Always remember to take safety precautions when working on a vehicle’s electrical system. If you’re not comfortable performing these steps, it’s advisable to seek help from a qualified technician.