SHIFT-BY-WIRE SYSTEM [A71M]


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Outline

•  A shift-by-wire system has been adopted which performs shift changes using electrical signals and an actuator instead of shift cables.
•  With the adoption of the shift-by-wire system, functions (Auto P function, shift position restrictions) have been achieved that allow the vehicle to partially control the shift position according to the vehicle conditions and the operations of the driver.

Construction


Structural view

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•  The shift-by-wire system consists of the following parts.

Part name

Function

Reference

Parking lock actuator (EPL)
The parking lock actuator performs the parking lock/unlock by driving the manual shaft using the built-in motor and gears.
Selector lever (ECL)
The shift position sensor in the selector lever detects the driver’s selector lever operation and sends it to the PCM via CAN communication.
PCM
Receives information from each module and determines the shift position change.
Sends a shift position change request signal to the parking lock actuator and DMCM.
(See PCM.)
DMCM
Switches the electric motor rotation direction based on the request signal from the PCM.
(See INVERTER.)
BCM
Relays CAN communication between each module for the shift-by-wire system.
Indicator
Indicates the actual shift position for the driver.
Shift position indication
Shift System Warning Indication/Warning Light
Warns the driver of a malfunction in the shift-by-wire system.
Shift position warning beep
Notifies the driver by a warning beep if the selector lever position is different than the actual shift position.
Selector lever not P reminder warning beep
Notifies the driver that the selector lever is not in the P position by a warning beep to prevent the driver from leaving the vehicle with the selector lever in a position other than the P position.


System Wiring Diagram

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Function

•  The shift position sensor in the selector lever detects the driver’s selector lever operation and sends a selector lever operation position signal to the PCM via CAN communication. When the PCM receives the signal, it determines the shift position change.
•  The EPL switches the parking lock and unlock, and the DMCM switches the electric motor rotation direction.
•  The shift-by-wire system has the following functions to enhance safety.

Function

Outline

Reference

Auto P function
If the vehicle detects an operation by the driver intending to leave the vehicle with the shift position in a position other than P position, the vehicle switches the shift position to P position automatically.
Shift position restrictions
If a specific operation by the driver is detected while accelerating from a standstill or driving, the vehicle restricts the shift position switching for safety.


Operation


Control outline

•  Detects the driver’s selector lever operation and sends a signal to the PCM as shift position information. The PCM calculates the control content based on the signals from input parts of many different sensors and switches, and sends operation request signals to the DMCM, parking lock actuator, and necessary indications/warning lights.
•  The PCM performs operation determination for the Auto P function and shift position restrictions according to the driving scenario.


D position/R position switching

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•  When the selector lever is shifted to the D, R, and N positions, the selector lever sends (1) a selector lever operation position signal to the PCM via CAN communication.
•  When the PCM receives the selector lever operation position signal, it determines (2) the availability of shift switching and sends (3) a electric motor rotation direction command signal to the DMCM via CAN communication.
•  When the DMCM receives the electric motor rotation direction command signal, it switches (4) the electric motor rotation direction. As a result, the vehicle forward/reverse is switched (5).


Parking lock/unlock function

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•  When the driver selects P position, the selector lever sends (1) a selector lever operation position signal to the PCM via CAN communication.
•  When the PCM receives the selector lever operation position signal, it determines (2) the availability of shift switching and sends (3) a parking lock/unlock command signal to the parking lock actuator via CAN communication.
•  When the parking lock actuator receives the parking lock/unlock command signal, it drives (4) the built-in motor. As a result,the parking lock/unlock is switched (5).


Auto P function

•  For the Auto P function control, refer to the Auto P function item.(See AutoP FUNCTION [A71M (E)].)


Shift position restrictions

•  For the shift position restrictions control, refer to the misoperation prevention function item. (See SHIFT POSITION RESTRICTIONS [A71M].)


Warning/indication/alarm function

•  For the warning/indication/alarm operation, refer to the warning/indication/alarm item. (See WARNING/INDICATION/ALARM [A71M].)