U1848 – Body Control Module Communication Fault

The ODBII code U1848: Body Control Module Communication Fault 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 U1848 is generally considered moderate to severe.

Common Causes For: U1847 U1847: Instrument Cluster Communication Failure

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

Common misdiagnosis for U1848 U1848: Body Control Module Communication Fault

• Faulty Body Control Module (BCM)
• Wiring issues or shorts in the communication lines
• Faulty or corroded connectors
• Issues with other control modules (e.g., Engine Control Module, Transmission Control Module)
• Battery or charging system problems
• Software or firmware issues in the BCM
• Grounding problems
• Faulty sensors or actuators related to the BCM
• Intermittent electrical issues
• Problems with the vehicle’s CAN bus system

Common Troubleshooting Steps

The OBD-II code U1848 indicates a communication fault 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 Other Codes: Use an OBD-II scanner to check for any additional trouble codes. Sometimes, other codes can provide context or lead to the root cause of the U1848 code.
• Inspect Wiring and Connectors:
• Visually inspect the wiring and connectors related to the BCM and other modules. 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. Ensure that there are no unintended connections between wires that could cause communication faults.
• Test the Body Control Module:
• If the wiring and connectors appear to be in good condition, the BCM itself may be faulty. You can test the BCM by checking its power and ground circuits.
• If possible, swap the BCM with a known good unit to see if the problem persists.
• Inspect Other Modules:
• Since the BCM communicates with other modules, check those modules for faults. Look for any codes or issues that may indicate a problem with another module affecting communication.
• Check for Software Updates:
• Sometimes, communication issues can be resolved with a software update. Check with the vehicle manufacturer or a dealership to see if there are any updates available for the BCM or other related modules.
• Perform a Network Test:
• Use a scan tool capable of performing a network test to check the communication between modules. This can help identify if the issue is isolated to the BCM or if it involves other modules.
• Clear Codes and Test Drive:
• After performing the above checks and repairs, clear the trouble codes and take the vehicle for a test drive to see if the U1848 code returns.
• Consult Technical Service Bulletins (TSBs):
• Check for any TSBs related to the U1848 code for your specific vehicle make and model. Manufacturers may have specific recommendations or known issues that can help in troubleshooting.
• Seek Professional Help:
• If you are unable to resolve the issue after these steps, it may be best to consult a professional mechanic or an automotive technician with experience in electrical systems and BCM diagnostics. By following these steps, you should be able to identify and resolve the communication fault associated with the U1848 code.