What causes code p1698?

Code P1698 typically indicates a communication issue between the engine control module (ECM) and the transmission control module (TCM). This can be caused by a faulty wiring harness, poor connections, or a malfunctioning TCM or ECM. Additionally, issues with the vehicle's battery or charging system can contribute to this code. Diagnosing the problem often requires checking the wiring, connectors, and the functionality of the modules involved.