U1745 – Transmission Control Module Communication Error

The ODBII code U1745 indicates a communication error between the Transmission Control Module (TCM) and other control modules in the vehicle, suggesting a possible issue with wiring, connectors, or the TCM itself.

The severity of ODBII code U1745 is moderate.

Common Causes For: U1744 U1744: Transmission Control Module Communication Error

• Faulty Transmission Control Module (TCM)
• Damaged wiring or connectors
• Poor ground connections
• Faulty Engine Control Module (ECM)
• Software issues or programming errors
• Corroded terminals
• Intermittent electrical connections
• Low battery voltage or power supply issues
• Faulty CAN bus communication
• Malfunctioning sensors related to transmission

Common misdiagnosis for U1745 U1745: Transmission Control Module Communication Error

• 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)
• Battery or charging system problems
• Software or firmware issues in the TCM or ECM
• Grounding issues in the electrical system

Common Troubleshooting Steps

The OBD-II code U1745 indicates a communication error between the Transmission Control Module (TCM) and other modules in the vehicle’s network. 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. Addressing other related codes may help resolve the U1745 code.
• 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.
• **Repair or Replace: Repair any damaged wires or connectors and ensure all connections are secure.
• 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.
• **Ground Connections: Ensure that the ground connections for the TCM are clean and secure.
• Inspect the TCM: **Physical Condition: Check the TCM for any signs of physical damage or water intrusion.
• **Reprogramming: If the TCM is suspected to be faulty, it may need to be reprogrammed or replaced.
• Check for Communication Issues: **CAN Bus: Inspect the Controller Area Network (CAN) bus for any faults. Use a scan tool to monitor communication between modules.
• **Network Integrity: Ensure that all modules on the network are functioning correctly and that there are no communication interruptions.
• Test the TCM: If possible, test the TCM in another vehicle of the same make and model to determine if the module is functioning properly.
• Clear Codes and Test Drive: After performing 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 Technical Service Bulletins (TSBs): Check for any manufacturer-specific TSBs related to the U1745 code, as there may be known issues or recommended fixes.
• Seek Professional Help: If the issue persists after performing the above steps, consider consulting a professional mechanic or technician who specializes in automotive electronics. By following these troubleshooting steps, you can systematically identify and resolve the underlying issue causing the U1745 code.