The Brake Band is incorrectly adjusted.

Adjust the Brake Band.

Loss of fluid in the return line between the accumulator and the Brake Band.

Replace the Brake Band Valve.

Loss of fluid in Clutch C3 or in the Fluid Circuit.

1. Search for the leaking part.
2. Replace the leaking part.

A defective or a blocked Brake Band Valve.

Refer to DTC P1850 Brake Band Apply Solenoid Circuit .

The fluid pressure is incorrect.

Perform the Transmission Fluid Check