U1902 – Instrument Cluster CAN Communication Fault

The ODBII code U1902: Instrument Cluster CAN Communication Fault indicates a communication issue between the instrument cluster and the vehicle’s Controller Area Network (CAN), which may affect the functionality of the cluster and related systems.

Moderate.

Common Causes For: U1901 CAN Communication Bus Fault.

• Faulty instrument cluster
• Damaged or corroded wiring
• Poor connections or loose terminals
• Failed CAN bus module
• Short circuit in the CAN bus
• Faulty or damaged CAN bus transceiver
• Software issues or programming errors
• Interference from aftermarket devices or modifications

Common misdiagnosis for U1902 U1902: Instrument Cluster CAN Communication Fault

• Faulty instrument cluster
• Bad wiring or connectors
• Defective CAN bus module
• Power supply issues
• Faulty body control module (BCM)
• Incorrectly programmed or calibrated modules
• Faulty sensors or actuators on the CAN network
• Software glitches or updates needed

Common Troubleshooting Steps

The OBD-II code U1902 indicates a communication fault on the Controller Area Network (CAN) bus, specifically related to the instrument cluster. This can be caused by various issues, including wiring problems, faulty components, or issues with the CAN bus itself. Here are some common troubleshooting steps to diagnose and resolve the U1902 code:

• 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 and CAN bus for any signs of damage, corrosion, or loose connections.
• **Repair or Replace: Repair any damaged wires or connectors and ensure all connections are secure.
• Test the CAN Bus: **CAN Bus Voltage: Use a multimeter to check the voltage levels on the CAN bus wires. The typical voltage should be around 2.5V when the bus is idle.
• **Signal Integrity: Use an oscilloscope to check the signal integrity on the CAN bus. Look for clean square wave signals without excessive noise.
• Check for Short Circuits: Inspect the CAN bus wiring for any short circuits to ground or to other wires. This can cause communication issues.
• Inspect the Instrument Cluster: **Functionality Check: Ensure that the instrument cluster is functioning properly. Look for any signs of failure, such as non-working gauges or warning lights.
• **Reprogram or Replace: If the instrument cluster is faulty, it may need to be reprogrammed or replaced.
• Check Other Modules: Since the CAN bus connects multiple modules, check other modules (like the Engine Control Module, Transmission Control Module, etc.) for communication issues. A fault in another module can affect the entire network.
• Perform a Network Test: If available, use a scan tool with network testing capabilities to check the communication between modules on the CAN bus.
• Clear Codes and Test Drive: After performing repairs, clear the trouble codes and take the vehicle for a test drive to see if the U1902 code returns.
• Consult Technical Service Bulletins (TSBs): Check for any manufacturer-specific TSBs related to the U1902 code or instrument cluster issues. There may be known fixes or recalls.
• Seek Professional Help: If the issue persists after performing these steps, consider seeking help from a professional mechanic or automotive technician who has experience with CAN bus systems. By following these troubleshooting steps, you should be able to identify and resolve the underlying issue causing the U1902 code.