U1873 – refers to a communication issue between the Body Control Module (BCM) and the Instrument Panel Cluster (IPC).

The ODBII code U1873 indicates a communication issue between the Body Control Module (BCM) and the Instrument Panel Cluster (IPC), suggesting a failure in data exchange between these two components.

The severity of ODBII code U1873 is generally considered moderate.

Common Causes For: U1872 U1872: “Control Module Communication Failure”

• Faulty Body Control Module (BCM)
• Faulty Instrument Panel Cluster (IPC)
• Damaged wiring or connectors between BCM and IPC
• Corrosion in connectors
• Poor ground connections
• Software issues or programming errors
• Intermittent electrical connections
• Short circuits in the communication lines

Common misdiagnosis for U1873 refers to a communication issue between the Body Control Module (BCM) and the Instrument Panel Cluster (IPC).

• Faulty Body Control Module (BCM)
• Faulty Instrument Panel Cluster (IPC)
• Wiring issues or shorts in communication lines
• Corroded or loose connectors
• Power supply issues to BCM or IPC
• Software or firmware issues in BCM or IPC
• Faulty sensors or input devices related to BCM or IPC
• Grounding issues affecting communication
• Other communication network faults (e.g., CAN bus issues)

Common Troubleshooting Steps

When dealing with OBD-II code U1873, which indicates a communication issue between the Body Control Module (BCM) and the Instrument Panel Cluster (IPC), you can follow these common troubleshooting steps:

• Check for Additional Codes: Before diving into specific troubleshooting, check for any other diagnostic trouble codes (DTCs) that may be present. This can provide more context about the issue.
• Inspect Wiring and Connectors:
• Visually inspect the wiring harness and connectors between the BCM and IPC for any signs of damage, corrosion, or loose connections.
• Ensure that all connectors are securely plugged in and that there are no bent pins.
• Test the Power and Ground:
• Verify that the BCM and IPC are receiving the correct voltage and ground. Use a multimeter to check for proper voltage at the connectors.
• Check for any blown fuses related to the BCM or IPC.
• Check for Short Circuits:
• Use a multimeter to check for short circuits in the wiring between the BCM and IPC. This includes checking for continuity where there shouldn’t be any.
• Inspect the BCM and IPC:
• If the wiring and connections are intact, the issue may lie within the BCM or IPC itself. Check for any visible damage or signs of failure.
• If possible, perform a software update on the BCM and IPC, as outdated software can sometimes cause communication issues.
• Perform a Network Test:
• Use a scan tool to perform a network test to see if the BCM and IPC can communicate with other modules in the vehicle. This can help isolate the problem.
• Check for Interference:
• Look for any aftermarket devices or modifications that may interfere with the communication between the BCM and IPC.
• Clear Codes and Test Drive:
• After performing the above checks and repairs, clear the codes using a scan tool and take the vehicle for a test drive to see if the code returns.
• Replace Faulty Components:
• If all else fails and the issue persists, consider replacing the BCM or IPC, as one of these components may be faulty.
• Consult Service Manual:
• Refer to the vehicle’s service manual for specific diagnostic procedures and wiring diagrams related to the BCM and IPC. If you are not comfortable performing these steps or if the issue persists after your troubleshooting, it may be best to consult a professional mechanic or technician for further diagnosis and repair.