U2114 Lost Communication with the Transmission Control Module (TCM)

Definition

Common causes

• Faulty Transmission Control Module (TCM)
• Damaged wiring or connectors
• Poor electrical connections
• Failed or malfunctioning Engine Control Module (ECM)
• Blown fuses
• Corroded terminals
• Software issues or updates needed
• Faulty CAN bus communication
• Low battery voltage or power supply issues
• Transmission fluid issues (e.g., low fluid level)

Common misdiagnoses

• Faulty Transmission Control Module (TCM)
• Wiring issues or damaged connectors
• Faulty Engine Control Module (ECM)
• Low transmission fluid levels
• Faulty sensors (e.g., speed sensors)
• Corrupted software or firmware in the TCM
• Battery or charging system issues
• Grounding problems
• Faulty transmission solenoids
• Issues with the vehicle's CAN bus system

Troubleshooting steps

1. 1. Check for Other Codes

   Use an OBD-II scanner to check for any additional trouble codes. Sometimes, other codes can provide context or indicate related issues

2. 2. Inspect Wiring and Connectors

   Visual Inspection: Check the wiring harness and connectors related to the TCM for any signs of damage, corrosion, or loose connections

3. 3. Connector Pins

   Ensure that the pins in the connectors are not bent, corroded, or pushed back

4. 4. Check Power and Ground

   Power Supply: Verify that the TCM is receiving the correct voltage. Use a multimeter to check the power supply to the TCM

5. 5. Ground Connections

   Ensure that the ground connections for the TCM are secure and free of corrosion

6. 6. Inspect the TCM

   Physical Condition: Check the TCM for any signs of physical damage or water intrusion

7. 7. Reprogramming

   If applicable, consider reprogramming or updating the TCM software, as a software glitch can sometimes cause communication issues

8. 8. Scan Tool Communication

   Communication Check: Use a scan tool to see if you can communicate with the TCM. If you cannot, it may indicate a problem with the TCM itself or the communication lines

9. 9. Other Modules

   Check if you can communicate with other modules in the vehicle. If other modules are also unresponsive, it may indicate a broader communication issue

10. 10. Check for Bus Communication Issues

    CAN Bus: If your vehicle uses a Controller Area Network (CAN) bus, check for issues on the bus. Look for short circuits, open circuits, or other faults that could disrupt communication

11. 11. Termination Resistors

    Ensure that the termination resistors are present and functioning correctly

12. 12. Test the TCM

    If all other checks are satisfactory, consider testing the TCM. This may involve swapping it with a known good unit if available

13. 13. Check for Environmental Factors

    Temperature: Extreme temperatures can affect electronic components. Ensure that the TCM is not exposed to excessive heat or moisture

14. 14. Clear Codes and Test Drive

    After performing repairs or checks, clear the codes and take the vehicle for a test drive to see if the code returns

15. 15. Consult Technical Service Bulletins (TSBs)

    Check for any manufacturer-specific TSBs related to the U2114 code or TCM communication issues. There may be known fixes or recalls.1

16. 16. Professional Diagnosis

    If the issue persists after all troubleshooting steps, consider seeking help from a professional mechanic or dealership, as they may have specialized tools and knowledge for your specific vehicle. By following these steps, you should be able to identify the root cause of the U2114 code and take appropriate action to resolve the communication issue with the Transmission Control Module