U1718 – Transmission Control Module Communication Error

The ODBII code U1718 indicates a communication error between the Transmission Control Module (TCM) and other control modules in the vehicle, suggesting a potential issue with data transmission or connectivity.

The severity of ODBII code U1718 is moderate.

Common Causes For: U1717 U1717: Transmission Control Module Communication Error

• Faulty Transmission Control Module (TCM)
• Damaged wiring or connectors
• Poor electrical connections
• Failed or malfunctioning engine control module (ECM)
• Software issues or outdated firmware
• Corroded terminals
• Short circuits in the wiring harness
• Faulty sensors related to transmission operation
• Issues with the vehicle’s battery or charging system
• Interference from aftermarket modifications or devices

Common misdiagnosis for U1718 U1718: Transmission Control Module Communication Error

• Faulty Transmission Control Module (TCM)
• Wiring or connector issues
• Faulty Engine Control Module (ECM)
• Transmission fluid issues
• Sensor malfunctions
• Battery or charging system problems
• Grounding issues
• Software or firmware issues in the TCM or ECM

Common Troubleshooting Steps

The OBD-II code U1718 indicates a communication error between the Transmission Control Module (TCM) and other control modules in the vehicle. Here are some common troubleshooting steps to diagnose and resolve this issue:

• Check for Other Codes: Use an OBD-II scanner to check for any additional trouble codes. Sometimes, related codes can provide more context for the issue.
• Inspect Wiring and Connectors:
• Visually inspect the wiring harness and connectors associated with the TCM. Look for signs of damage, corrosion, or loose connections.
• Ensure that all connectors are securely plugged in and that there are no bent pins.
• Check Power and Ground:
• Verify that the TCM is receiving the correct voltage and ground. Use a multimeter to check the power supply and ground connections to the TCM.
• If there is no power or ground, trace the wiring back to the source to identify any breaks or shorts.
• Test the TCM:
• If the wiring and connections are intact, the TCM itself may be faulty. Testing the TCM may require specialized equipment or a professional diagnostic tool.
• If possible, swap the TCM with a known good unit to see if the problem persists.
• Check for Software Updates:
• Sometimes, communication issues can be resolved with a software update. Check with the vehicle manufacturer or a dealership to see if there are any updates available for the TCM.
• Inspect Other Modules:
• Since the TCM communicates with other modules, check those modules for faults. Issues in other control modules can sometimes cause communication errors.
• Look for Interference:
• Ensure that there are no aftermarket devices or modifications that could be interfering with the communication between the TCM and other modules.
• Clear Codes and Test Drive:
• After performing the above checks and repairs, clear the trouble codes using the OBD-II scanner and take the vehicle for a test drive to see if the code returns.
• Consult a Professional:
• If the issue persists after performing these steps, it may be necessary to consult a professional mechanic or technician who has experience with transmission control systems and can perform more advanced diagnostics. By following these steps, you should be able to identify and resolve the communication error associated with the U1718 code.