U1592 – Lost Communication with the Body Control Module (BCM) – Bus Off.

The ODBII code U1592 indicates that there is a communication failure between the vehicle’s control modules, specifically indicating that the Body Control Module (BCM) is not responding or is offline, often due to a bus communication issue.

The severity of ODBII code U1592 is generally considered moderate to severe.

Common Causes For: U1591 U1591: “Vehicle Communication Bus Malfunction”

• Faulty Body Control Module (BCM)
• Damaged wiring or connectors
• Short circuit in the communication lines
• Faulty or corroded ground connections
• Issues with the CAN bus system
• Malfunctioning power supply to the BCM
• Software or firmware issues in the BCM
• Other modules on the bus malfunctioning

Common misdiagnosis for U1592 Lost Communication with the Body Control Module (BCM) – Bus Off.

• Faulty Body Control Module (BCM)
• Wiring issues or shorts in the communication lines
• Faulty or corroded connectors
• Issues with the power supply to the BCM
• Faulty Instrument Cluster
• Problems with the Engine Control Module (ECM)
• Malfunctioning CAN bus system
• Software or firmware issues in the BCM
• Grounding issues in the electrical system
• Faulty sensors or actuators connected to the BCM

Common Troubleshooting Steps

When dealing with the OBD-II code U1592, which indicates “Lost Communication with the Body Control Module (BCM) – Bus Off,” there are several common troubleshooting steps you can follow to diagnose and potentially resolve the issue. Here’s a structured approach:

• Check for Additional Codes: Use an OBD-II scanner to check for any other trouble codes that may be present. This can provide more context and help identify related issues.
• 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 damaged.
• Check the BCM: **Power and Ground: Verify that the BCM is receiving proper power and ground. Use a multimeter to check voltage at the BCM connector.
• **Module Functionality: If possible, test the BCM in another vehicle or replace it with a known good unit to see if the problem persists.
• Inspect the CAN Bus: **Bus Communication: The BCM communicates over the Controller Area Network (CAN) bus. Check for proper communication between the BCM and other modules.
• **Termination Resistors: Ensure that the CAN bus has the correct termination resistors in place and that they are functioning properly.
• Check for Short Circuits: Use a multimeter to check for short circuits in the wiring harness that could be causing communication issues.
• Scan for Communication Issues: Use a professional scan tool to monitor the communication on the CAN bus. Look for any irregularities or interruptions in communication between modules.
• Inspect for Environmental Factors: Check for any environmental factors that could affect the BCM, such as moisture or extreme temperatures.
• Reset the System: Clear the trouble codes using the OBD-II scanner and see if the code returns after a test drive. Sometimes, a reset can resolve temporary communication issues.
• 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 known issues.
• Consult Technical Service Bulletins (TSBs): Look for any TSBs related to the U1592 code for your specific vehicle make and model. Manufacturers may have specific recommendations or known fixes.1
• 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 and communication issues. By following these steps, you should be able to identify the root cause of the U1592 code and take appropriate action to resolve the issue.