U1544 – BCM Communication Failure

The ODBII code U1544: BCM Communication Failure indicates a communication issue between the Body Control Module (BCM) and other modules in the vehicle’s network.

The severity of ODBII code U1544: BCM Communication Failure is moderate.

Common Causes For: U1543 U1543: ECM-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 issues or programming errors in the BCM
• Low battery voltage or power supply issues
• Interference from aftermarket accessories or modifications

Common misdiagnosis for U1544 U1544: BCM Communication Failure

• Faulty Body Control Module (BCM)
• Wiring issues or shorts in the communication lines
• Defective or corroded connectors
• Malfunctioning other control modules
• Battery or power supply issues
• Software or firmware glitches in the BCM
• Faulty sensors or actuators related to the BCM
• Grounding issues in the electrical system

Common Troubleshooting Steps

The OBD-II code U1544 indicates a communication failure between the Body Control Module (BCM) and other modules in the vehicle’s network. 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:
• Visually inspect the wiring harness and connectors associated with the BCM and other modules for signs of damage, corrosion, or loose connections.
• Pay special attention to any connectors that may have been disturbed during repairs or maintenance.
• Check Power and Ground:
• Ensure that the BCM is receiving proper power and ground. Use a multimeter to check voltage at the BCM connector.
• Verify that the ground connections are clean and secure.
• Test the BCM:
• If possible, test the BCM for proper operation. This may involve using a scan tool to check for communication with other modules.
• If the BCM is suspected to be faulty, it may need to be replaced or reprogrammed.
• Inspect the CAN Bus:
• The BCM communicates with other modules via the Controller Area Network (CAN) bus. Check for any issues with the CAN bus wiring, such as shorts or opens.
• Use an oscilloscope or a CAN bus tester to monitor the communication signals on the bus.
• Check for Interference:
• Look for any aftermarket devices or modifications that may interfere with the vehicle’s communication network, such as alarms, remote starters, or stereo systems.
• Perform a Hard Reset:
• Disconnect the vehicle’s battery for a few minutes to reset the modules. Reconnect the battery and see if the code returns.
• Update Software:
• Check if there are any software updates available for the BCM or other modules. Sometimes, communication issues can be resolved with a software update.
• Consult Technical Service Bulletins (TSBs):
• Look for any TSBs related to the U1544 code for your specific vehicle make and model. Manufacturers may have specific recommendations or known issues.
• 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 communication issues. By following these steps, you should be able to identify and resolve the underlying cause of the U1544 code.