The automatic transmissions are combined with change solenoids. The quantity of these components depends on the internal gears. Their function is to control the movement of the transmission fluid between the different hydraulic circuits, to achieve the changes of ratio at the most suitable moment. Because of this process, a higher performance of the engine is obtained.
If a malfunction is detected in the “E” shifting solenoid circuit, different codes are activated which will depend on the vehicle model and transmission used. In the case of DTC code P0770 OBDII indicates a general malfunction in the “E” solenoid circuit.