POST UPDATED IN June, 2023
The step motor has four aspects that have some variations according to the signal provided by the TCM (Transmission Control Module). As a result, the flow of line pressure to the primary pulley changes, and the pulley ratio is controlled. With this diagnosis, it is detected when the electrical system is working properly, but there are instabilities from the mechanical system. It also detects when the state of the speed change mechanism in the unit shows irregularities in its performance.
OBDII fault code P1778 is set on Infiniti and Nissan vehicles when there is a big difference between the number of steps of the stepper motor and the actual transmission ratio.
OBD2 DTC P1778 is stored for the following reasons:
Steps to fix the P1778 OBDII diagnostic code are: