U1687 – Instrument Cluster Communication Failure

The ODBII code U1687: Instrument Cluster Communication Failure indicates a loss of communication between the vehicle’s instrument cluster and other control modules, which may affect the functionality of the dashboard gauges and warning lights.

The severity of ODBII code U1687 is generally considered moderate to severe.

Common Causes For: U1685 U1685: ECM-BCM Communication Failure

• Faulty instrument cluster
• Damaged wiring or connectors
• Poor ground connections
• Failed communication module
• Corroded terminals
• Software issues or bugs
• Faulty CAN bus communication
• Low battery voltage or power supply issues

Common misdiagnosis for U1687 U1687: Instrument Cluster Communication Failure

• Faulty instrument cluster
• Bad wiring or connectors
• Faulty body control module (BCM)
• Malfunctioning engine control module (ECM)
• Issues with the CAN bus system
• Power supply problems
• Grounding issues
• Faulty sensors or actuators related to the cluster
• Software or firmware issues in the instrument cluster or BCM
• Incorrectly diagnosed electrical shorts or opens in the circuit.

Common Troubleshooting Steps

The OBD-II code U1687 indicates an “Instrument Cluster Communication Failure.” This code typically suggests that there is a communication issue between the instrument cluster 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 trouble codes that may be present. Other codes can provide additional context for the issue.
• Inspect Wiring and Connectors: **Visual Inspection: Check the wiring harness and connectors related to the instrument cluster for any signs of damage, corrosion, or loose connections.
• **Connector Pins: Ensure that the pins in the connectors are not bent or corroded.
• Check Power and Ground: Verify that the instrument cluster is receiving the proper power supply and ground. Use a multimeter to check voltage and ground continuity.
• Test the Instrument Cluster: If possible, perform a self-test of the instrument cluster to see if it operates correctly. Some vehicles have a built-in diagnostic mode for this purpose.
• Inspect the CAN Bus: The instrument cluster typically communicates over the Controller Area Network (CAN) bus. Check for any issues with the CAN bus wiring, such as shorts or opens.
• Use a CAN bus scanner to monitor the communication on the bus and check for any abnormalities.
• Check for Module Communication: Use a scan tool to check if other modules (like the Engine Control Module, Body Control Module, etc.) are communicating properly. If other modules are also having communication issues, it may indicate a broader network problem.
• Look for Software Updates: Check if there are any software updates available for the vehicle’s modules. Sometimes, communication issues can be resolved with a software update.
• Reset the Codes: Clear the trouble codes using the OBD-II scanner and see if the code returns after a short drive. If it does, further investigation is needed.
• Replace Faulty Components: If the instrument cluster is determined to be faulty after testing, consider replacing it. If other modules are found to be faulty, they may also need replacement.
• Consult Service Manual: Refer to the vehicle’s service manual for specific diagnostic procedures and wiring diagrams related to the instrument cluster and communication systems.1
• Seek Professional Help: If the issue persists after performing these steps, it may be best to consult a professional mechanic or technician who has experience with the specific make and model of your vehicle. By following these troubleshooting steps, you should be able to identify and resolve the issue related to the U1687 code.