Lost Communication with TCM

What This Means

Communication has been lost between the engine computer and the transmission control module. The CAN bus network connecting these modules is interrupted.

Common Symptoms

• Transmission stuck in limp mode
• No shifting or harsh shifts
• Multiple warning lights
• Speedometer may not work

Common Causes

• Failed TCM
• CAN bus wiring fault
• Corroded connector at TCM
• Power or ground issue to TCM
• Water intrusion

Estimated Repair Cost