U1508 – BCM Communication Failure

The ODBII code U1508 indicates a communication failure between the Body Control Module (BCM) and other modules in the vehicle’s network, suggesting a potential issue with wiring, connectors, or the BCM itself.

The severity of ODBII code U1508: “BCM Communication Failure” is generally considered moderate to severe.

Common Causes For: U1507 U1507: “Module Communication Failure”

• Faulty Body Control Module (BCM)
• Damaged wiring or connectors
• Poor ground connections
• Corroded terminals
• Software issues or bugs in the BCM
• Malfunctioning communication network (CAN bus)
• Other module failures affecting communication
• Low battery voltage or power supply issues

Common misdiagnosis for U1508 U1508: “BCM Communication Failure”

• Faulty Body Control Module (BCM)
• Wiring issues or shorts in the communication lines
• Defective or corroded connectors
• Malfunctioning Instrument Cluster
• Issues with the Powertrain Control Module (PCM)
• Faulty sensors or actuators
• Software or firmware issues in the BCM
• Battery or charging system problems
• Grounding issues
• Intermittent electrical faults

Common Troubleshooting Steps

The OBD-II code U1508 indicates a “BCM Communication Failure,” which typically means there is a problem with the communication between the Body Control Module (BCM) and other modules in the vehicle. Here are some common troubleshooting steps to diagnose and resolve this issue:

• Check for Additional Codes: Use an OBD-II scanner to check for any other trouble codes that may be present. Sometimes, multiple codes can provide more context for the issue.
• Inspect Wiring and Connectors: Visually inspect the wiring and connectors related to the BCM. Look for signs of damage, corrosion, or loose connections.
• Pay special attention to the ground connections, as poor grounding can lead to communication issues.
• Check for Short Circuits: Use a multimeter to check for short circuits in the wiring harness connected to the BCM. Ensure that there are no unintended connections between wires.
• Test the BCM: If possible, test the BCM to ensure it is functioning correctly. This may involve using specialized diagnostic equipment or swapping it with a known good unit.
• Inspect Other Modules: Check other modules that communicate with the BCM (e.g., Engine Control Module, Transmission Control Module) for faults. A failure in one module can affect communication with the BCM.
• Check for Software Updates: Verify if there are any software updates available for the BCM or other related modules. Sometimes, manufacturers release updates to fix communication issues.
• Perform a Network Test: Use a scan tool to perform a network test to see if the BCM is communicating with other modules. This can help identify if the issue is isolated to the BCM or if it affects other modules as well.
• Inspect Fuses: Check the fuses related to the BCM and other modules. A blown fuse can interrupt communication.
• Clear Codes and Test Drive: After performing any repairs or inspections, clear the trouble codes and take the vehicle for a test drive to see if the code returns.
• Consult Service Manual: Refer to the vehicle’s service manual for specific diagnostic procedures related to the BCM and communication issues. This can provide additional insights and steps tailored to your vehicle model.1
• Seek Professional Help: 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 U1508 code.