U2180 – CAN Bus Communication Failure

The ODBII code U2180 indicates a “CAN Bus Communication Failure,” meaning there is a problem with the communication between the vehicle’s control modules over the Controller Area Network (CAN) bus.

The severity of ODBII code U2180 is moderate to high.

Common Causes For: U2179 Lost Communication with the Body Control Module (BCM) – Bus Off.

• Faulty CAN bus wiring or connectors
• Short circuit in the CAN bus
• Open circuit in the CAN bus
• Faulty control modules
• Poor ground connections
• Interference from other electrical components
• Corroded or damaged connectors
• Software issues or bugs in control modules
• Low battery voltage or power supply issues
• Faulty termination resistors

Common misdiagnosis for U2180 U2180: “CAN Bus Communication Failure”

• Faulty ECU (Electronic Control Unit)
• Bad wiring or connectors
• Defective CAN Bus transceiver
• Power supply issues
• Grounding problems
• Faulty sensors
• Software glitches or updates needed
• Intermittent electrical issues
• Other communication protocol failures
• Faulty modules in the network

Common Troubleshooting Steps

The OBD-II code U2180 indicates a “CAN Bus Communication Failure.” This code typically points to issues with the Controller Area Network (CAN) bus, which is responsible for communication between various electronic control units (ECUs) in a vehicle. Here are some common troubleshooting steps to diagnose and resolve the issue:

• Check for Other Codes: Use an OBD-II scanner to check for any additional trouble codes. Other codes may provide more context or indicate which specific module is having communication issues.
• Inspect the Wiring and Connectors: Visually inspect the wiring harnesses and connectors associated with the CAN bus. Look for signs of damage, corrosion, or loose connections.
• Pay special attention to the connectors at the ECUs, as well as any junction points in the wiring.
• Test the CAN Bus Voltage: Use a multimeter to measure the voltage on the CAN High (CAN H) and CAN Low (CAN L) wires. The typical voltage levels should be around 2.5V when the bus is idle.
• Check for proper voltage levels while the vehicle is running. The CAN H should be around 2.5V to 3.5V, and the CAN L should be around 1.5V to 2.5V.
• Check for Short Circuits or Open Circuits: Use a multimeter to check for continuity in the CAN bus wiring. Look for any short circuits to ground or power, as well as open circuits that may disrupt communication.
• Inspect the ECUs: Identify the ECUs connected to the CAN bus. If one of the modules is malfunctioning, it can disrupt communication. Check for any signs of damage or failure in these modules.
• If possible, try disconnecting individual ECUs one at a time to see if the communication issue resolves, indicating a faulty module.
• Check for Interference: Look for any aftermarket devices or modifications that may interfere with the CAN bus communication. This includes alarm systems, stereo systems, or other electronic devices.
• Perform a Network Test: If you have access to a professional scan tool, perform a network test to check the status of the CAN bus and identify any communication failures between modules.
• Update or Reprogram ECUs: In some cases, updating or reprogramming the affected ECUs may resolve communication issues. Check with the manufacturer for any available software updates.
• Consult Technical Service Bulletins (TSBs): Check for any TSBs related to the specific make and model of the vehicle. Manufacturers may have issued guidance on known issues with the CAN bus.
• Seek Professional Help: If the issue persists after performing these steps, it may be necessary to consult a professional mechanic or automotive technician who has experience with CAN bus systems. By following these troubleshooting steps, you can systematically identify and resolve the underlying cause of the U2180 code.