U1662 – Lost Communication with Body Control Module (BCM).

The ODBII code U1662 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 U1662 is generally considered moderate to severe.

Common Causes For: U1661 Lost Communication with Body Control Module (BCM).

• Faulty Body Control Module (BCM)
• Damaged wiring or connectors
• Poor ground connection
• Corroded terminals
• Faulty communication network (CAN bus)
• Malfunctioning power supply to the BCM
• Software issues or programming errors
• Other module failures affecting communication

Common misdiagnosis for U1662 Lost Communication with Body Control Module (BCM)”.

• Faulty Body Control Module (BCM)
• Wiring issues or damaged connectors
• Faulty ignition switch
• Battery or charging system problems
• Faulty or corroded ground connections
• Other communication module failures
• Software or firmware issues in the BCM
• Faulty sensors or actuators related to the BCM

Common Troubleshooting Steps

When dealing with the OBD-II code U1662, 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, 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, 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 to the BCM.
• **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, the issue may be with 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: Check for any environmental factors that could affect the BCM, such as moisture or extreme temperatures.
• Perform a Hard Reset: Disconnect the battery for a few minutes to reset the vehicle’s electronic systems. Reconnect and see if the code returns.
• Consult Technical Service Bulletins (TSBs): Look for any TSBs related to the specific make and model of the vehicle that may address known issues with the BCM.
• 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 follow 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.