Circuit Description

Fig 1: Line Pressure & Current Flow Solenoid Graph

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

The throttle pressure that is applied to the primary regulator valve (which modulates the line pressure) causes the solenoid valve SLT, under electronic control, to precisely and minutely modulate and generate the line pressure according the extent of the accelerator pedal depressed or the output of engine power.

This reduces the function of the line pressure and provides smooth shifting.

Fig 2: Identifying Blinking Patter

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Upon receiving a signal of the throttle valve opening angle, the ECM controls the line pressure by sending a predetermined (^* ) duty ratio to the solenoid valve, modulating the line pressure and generating throttle pressure.

(^* ): Duty Ratio

The duty ratio is the ratio of the period of continuity in one cycle. For example, if A is the period of continuity in one cycle, and B is the period of non-continuity, then

Duty Ratio=A/ (A+B) x 100 (%)

Fig 3: DTC P1760 Detection Condition Table

Reference:

Check the waveform between terminals SLT+ and SLT- during the engine idling.

Fig 4: Identifying Waveform Between Terminals SLT + & SLT- Graph