Toyota Sienna Service Manual: System description

1. GENERAL DESCRIPTION

1.  The power seat control system is equipped with the following function:

•  The front seats are equipped with electric adjuster slide, reclining, lifter, front vertical and lumbar support adjustment functions.

2.  The power seat control system (w/ memory) is equipped with the following functions:

•  Individual seat positions for two different drivers can be stored for the slide, reclining, front vertical and lifter.
•  Similarly, power mirror positions for two different drivers can be stored. These are stored/restored together with the seat positions by pushing the seat memory switch.
•  The above operations are performed using the multiplex communication system.
•  As a safety precaution, the system does not allow seat position restoration unless the ignition switch is in the ON position and the shift lever is in the P position.
•  Manual adjustment of the lumbar support function can be performed even when the position control ECU and switch assembly (power seat control switch and ECU) is not functional.

  When the power seat control switch is operated, a command signal is sent to the position control ECU and switch assembly (power seat control switch and ECU). The position control ECU and switch assembly (power seat control switch and ECU) then activates the appropriate seat motor as needed.

  This memory system does not use a seat position sensor. The seat position is detected by counting pulses that are output when the motor turns. The position control ECU and switch assembly (power seat control switch and ECU) is designed so that a malfunction of the seat memory system will not interfere with seat control. The seat memory switch also sends signals to the position control ECU and switch assembly (power seat control switch and ECU) to memorize a given seat position. Two seat positions can be memorized. The seat memory switch is later used to send signals to the position control ECU and switch assembly (power seat control switch and ECU) to return the seat to either of the memorized positions.

2. FUNCTION OF MAIN COMPONENT (w/ MEMORY)

1.  The following functions are available.

3. SYSTEM OPERATION

1.  The front power seats adjustment and position memory are shown in the chart below

*: with Seat Position Memory System In the memory function, the memory switch operation signal is transferred from the outer mirror control ECU LH to the position control ECU and switch assembly (power seat control switch and ECU) via the multiplex communication line. Then, either the seat position is stored in memory or the previously stored seat position is recalled to set the appropriate seat position.