U1585 – BCM Communication Failure

The ODBII code U1585: BCM Communication Failure indicates a communication issue between the Body Control Module (BCM) and other modules in the vehicle’s network, potentially affecting various electrical functions.

The severity of ODBII code **U1585: BCM Communication Failure** is generally considered moderate to severe.

Common Causes For: U1367: Control Module Communication Fault

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

Common misdiagnosis for U1585: 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 other control modules (e.g., PCM, ECM)
• Battery or power supply problems
• Software or firmware issues in the BCM
• Grounding problems in the electrical system

Common Troubleshooting Steps

The OBD-II code **U1585: BCM Communication Failure** indicates a communication issue 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 Additional Codes: Use an OBD-II scanner to check for any other related trouble codes. This can provide more context about the issue and help identify if other modules are affected.
• Inspect Wiring and Connectors:
• Visually inspect the wiring and connectors related to the BCM and other modules in the communication network. Look for signs of damage, corrosion, or loose connections.
• Pay special attention to the ground connections, as poor grounding can lead to communication failures.
• Check for Short Circuits:
• Use a multimeter to check for short circuits in the wiring harness. A short to ground or power can disrupt communication between modules.
• Test the BCM:
• If the wiring and connectors appear to be in good condition, the BCM itself may be faulty. Testing the BCM may require specialized equipment or software.
• If possible, try swapping the BCM with a known good unit to see if the problem persists.
• Inspect Other Modules:
• Check other modules that communicate with the BCM. A failure in another module can sometimes cause communication issues.
• Ensure that all modules are functioning correctly and that their connections are secure.
• Check for Software Updates:
• Sometimes, communication issues can be resolved with a software update. Check with the manufacturer for any available updates for the BCM or other related modules.
• 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 reappears.
• Consult Technical Service Bulletins (TSBs):
• Look for any TSBs related to the U1585 code or BCM communication issues for your specific vehicle make and model. Manufacturers may have specific recommendations or known fixes.
• Professional Diagnosis:
• If the issue persists after performing the above steps, it may be necessary to seek professional help. A qualified technician can perform more advanced diagnostics and repairs. By following these steps, you can systematically identify and resolve the communication failure indicated by the U1585 code.