U1708 – Transmission Control Module Communication Error

The ODBII code U1708 indicates a communication error between the Transmission Control Module (TCM) and other control modules in the vehicle, suggesting a potential issue with wiring, connectors, or the TCM itself.

The severity of ODBII code U1708 is moderate to severe.

Common Causes For: U1707 CAN Communication Bus Fault.

• Faulty Transmission Control Module (TCM)
• Damaged wiring or connectors
• Poor electrical connections
• Failed or malfunctioning Engine Control Module (ECM)
• Software issues or programming errors
• Low battery voltage or electrical system problems
• Corroded or loose ground connections
• Faulty CAN bus communication
• Intermittent faults in the transmission system

Common misdiagnosis for U1708 U1708: 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 transmission sensors
• Software issues or programming errors
• Battery or charging system problems
• Grounding issues
• Faulty CAN bus communication
• Other transmission-related faults

Common Troubleshooting Steps

The OBD-II code U1708 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. Addressing other related codes may help resolve the U1708 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, consider reprogramming or updating the software if applicable.
• Check for Communication Issues: **CAN Bus Communication: Use a scan tool to monitor the CAN bus communication. Ensure that the TCM is communicating with other modules (e.g., Engine Control Module).
• **Network Integrity: Check for any issues with the CAN bus wiring, such as shorts or opens.
• Test the TCM: If all other checks are satisfactory, consider testing the TCM. This may involve using specialized diagnostic equipment or replacing the TCM with a known good unit to see if the issue persists.
• Clear Codes and Test Drive: After performing repairs or checks, 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 U1708 code or TCM communication issues. There may be known fixes or recalls.
• Seek Professional Help: If the issue persists after performing the above steps, it may be necessary to consult a professional mechanic or dealership for further diagnosis.Conclusion Troubleshooting a U1708 code involves a systematic approach to check for wiring issues, power supply, communication integrity, and the condition of the TCM itself. Always ensure safety and follow manufacturer guidelines when working on vehicle electronics.