U1542 – BCM Communication Failure

The ODBII code U1542 indicates a communication failure between the Body Control Module (BCM) and other modules in the vehicle’s network, which can lead to issues with various electrical systems and features.

The severity of ODBII code U1542: “BCM Communication Failure” is generally considered moderate to severe.

Common Causes For: U1541 U1541: “BCM Communication Failure”

• Faulty Body Control Module (BCM)
• Poor electrical connections or wiring issues
• Corroded connectors
• Malfunctioning sensors or components connected to the BCM
• Software or firmware issues in the BCM
• Low battery voltage or power supply issues
• Faulty communication lines (CAN bus issues)
• Grounding problems

Common misdiagnosis for U1542 U1542: “BCM Communication Failure”

• Faulty Body Control Module (BCM)
• Wiring issues or shorts in the communication lines
• Defective or corroded connectors
• Malfunctioning power supply to the BCM
• Issues with other control modules (e.g., PCM, ECM)
• Software glitches or outdated firmware
• Battery or charging system problems
• Grounding issues in the electrical system

Common Troubleshooting Steps

The OBD-II code U1542 indicates a “BCM Communication Failure,” which typically means that the Body Control Module (BCM) is not communicating properly with other modules in the vehicle. Here are some common troubleshooting steps to diagnose and resolve this issue:

• Check for Other Codes: Use an OBD-II scanner to check for any additional trouble codes. Other codes may provide more context or indicate related issues.
• Inspect Wiring and Connectors: **Visual Inspection: Check the wiring harnesses 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 damaged.
• 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 proper operation. This may involve using specialized diagnostic equipment or replacing the BCM with a known good unit to see if the issue persists.
• Inspect Other Modules: Check the communication between the BCM and other modules (e.g., PCM, ABS, etc.). If another module is malfunctioning, it may affect the BCM’s ability to communicate.
• Check for Short Circuits: Inspect the wiring for any short circuits that may be affecting communication. This can include checking for shorts to ground or power.
• Look for Software Issues: Ensure that the vehicle’s software is up to date. Sometimes, a software update can resolve communication issues between modules.
• Perform a Network Test: If equipped, use a scan tool to perform a network test to check for communication issues between modules on the CAN bus.
• Clear Codes and Test Drive: After performing any repairs or checks, clear the trouble codes and take the vehicle for a test drive to see if the code returns.
• Consult Technical Service Bulletins (TSBs): Check for any TSBs related to the U1542 code for your specific vehicle make and model. Manufacturers may have specific recommendations or known issues.1
• Seek Professional Help: If the issue persists after performing these steps, it may be necessary to consult a professional mechanic or dealership for further diagnosis. By following these steps, you can systematically identify and resolve the underlying cause of the U1542 code.