U2217 U2217: "CAN Bus Communication Failure

Definition

Common causes

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

Common misdiagnoses

• Faulty CAN Bus wiring
• Defective ECU (Engine Control Unit)
• Malfunctioning sensors
• Bad ground connections
• Faulty or corroded connectors
• Issues with other control modules
• Software glitches or outdated firmware
• Battery or power supply problems
• Interference from aftermarket accessories
• Faulty diagnostic tools or scanners

Troubleshooting steps

1. 1. 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 for the issue

2. 2. Inspect the CAN Bus Wiring

   Visual Inspection: Check the wiring and connectors associated with the CAN bus for any visible damage, corrosion, or loose connections

3. 3. Wiring Integrity

   Ensure that the wires are not frayed, pinched, or shorted to ground or power

4. 4. Check the CAN Bus Termination Resistors

   The CAN bus requires termination resistors (typically 120 ohms) at each end of the bus. Ensure that these resistors are present and functioning correctly

5. 5. Test the CAN Bus Voltage

   Use a multimeter to check the voltage levels on the CAN High (CAN H) and CAN Low (CAN L) lines. The typical voltage levels should be around 2.5V when idle, with variations when data is being transmitted

6. 6. Inspect Modules on the CAN Bus

   Identify all modules connected to the CAN bus. Check for any modules that may be malfunctioning or have failed, as this can disrupt communication

7. 7. Disconnect each module one at a time to see if the code clears or communication is restored

8. 8. Check for Ground Issues

   Ensure that all ground connections related to the CAN bus and the modules are secure and free of corrosion

9. 9. Scan for Module Communication

   Use a scan tool to check if you can communicate with all modules on the CAN bus. If some modules are unresponsive, it may indicate a problem with those specific modules

10. 10. Inspect for Interference

    Look for any aftermarket devices or modifications that may interfere with the CAN bus communication, such as alarms, stereo systems, or other electronic devices

11. 11. Perform a Network Test

    Some advanced scan tools can perform a network test to check the integrity of the CAN bus. This can help identify issues with specific modules or wiring

12. 12. Check Battery Voltage

    Ensure that the vehicle's battery is in good condition and fully charged. Low voltage can affect the performance of the CAN bus.1

13. 13. Reset the Codes

    After performing checks and repairs, clear the codes using the OBD-II scanner and take the vehicle for a test drive to see if the code returns.1

14. 14. Consult Technical Service Bulletins (TSBs)

    Check for any manufacturer-specific TSBs related to the U2217 code, as there may be known issues or recalls that apply to your vehicle.1

15. 15. 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 troubleshooting steps, you can systematically identify and resolve the underlying cause of the U2217 code