U2233 – CAN Bus Communication Failure

The ODBII code U2233 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 U2233 is moderate to high.

Common Causes For: U2231 Lost Communication with the Steering Angle Sensor.

• Faulty CAN bus wiring or connectors
• Short circuit in the CAN bus
• Open circuit in the CAN bus
• Faulty or malfunctioning ECU (Electronic Control Unit)
• Interference from other electrical components
• Corroded or damaged connectors
• Poor ground connections
• Software issues or bugs in the ECU
• Faulty termination resistors
• Low battery voltage or power supply issues

Common misdiagnosis for U2233 U2233: “CAN Bus Communication Failure”

• Faulty CAN Bus wiring
• Defective ECU (Engine Control Unit)
• Malfunctioning sensors
• Bad ground connections
• Corrupted software or firmware
• Faulty connectors or terminals
• Issues with other communication protocols
• Battery or power supply problems
• Intermittent electrical connections
• Faulty diagnostic tools or scanners

Common Troubleshooting Steps

When dealing with OBD-II code U2233, which indicates a “CAN Bus Communication Failure,” there are several common troubleshooting steps you can take to diagnose and potentially resolve the issue. Here’s a structured approach:

• Check for Additional Codes: Use an OBD-II scanner to check for any other trouble codes that may be present. Sometimes, multiple codes can provide more context about the issue.
• Inspect the CAN Bus Wiring: **Visual Inspection: Check the wiring harnesses and connectors related to the CAN bus for any signs of damage, corrosion, or loose connections.
• **Connector Pins: Ensure that the pins in the connectors are not bent, corroded, or pushed back.
• Test the CAN Bus Voltage: Use a multimeter to measure the voltage on the CAN High and CAN Low 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.
• Check for Short Circuits: Inspect the CAN bus wiring for any short circuits to ground or to each other. This can cause communication failures.
• Inspect Modules on the CAN Bus: Identify all modules connected to the CAN bus (e.g., engine control module, transmission control module, ABS module, etc.).
• Check for any malfunctioning modules that may be causing the communication failure. Disconnecting modules one at a time can help isolate the problem.
• Test the CAN Bus with a Scanner: Use a professional-grade scan tool to monitor the CAN bus data. Look for any irregularities in the data being transmitted.
• Some scan tools can perform a “CAN bus test” to check for communication issues.
• Check for Interference: Ensure that there are no aftermarket devices or modifications that could be interfering with the CAN bus communication.
• Inspect Ground Connections: Check the ground connections for the modules on the CAN bus. Poor grounding can lead to communication issues.
• Perform a Network Test: If available, use a CAN bus diagnostic tool to perform a network test. This can help identify which module is not communicating properly.
• Clear Codes and Test Drive: After performing the checks and repairs, clear the trouble codes and take the vehicle for a test drive to see if the code returns.1
• Consult Technical Service Bulletins (TSBs): Check for any manufacturer-specific TSBs related to the U2233 code or CAN bus issues for your vehicle make and model.1
• Seek Professional Help: If the issue persists after performing these steps, it may be necessary to consult a professional mechanic or technician who specializes in automotive electronics. By following these steps, you should be able to identify and resolve the underlying cause of the U2233 code.