Nissan Quest E52. Manual - part 1200

TM-30

< SYSTEM DESCRIPTION >

[CVT: RE0F09B]

SYSTEM

Appropriate line pressure and secondary pressure suitable for driving condition are determined based on the
accelerator pedal position, engine speed, primary pulley (input) speed, secondary pulley (output) speed, input
torque, stop lamp switch signal, transmission range switch signal, lock-up signal, power voltage, target shift
ratio, oil temperature and oil pressure.

Secondary Pressure Feedback Control

In normal oil pressure control and oil pressure control in shifting, highly accurate secondary pressure is deter-
mined by detecting the secondary pressure using an oil pressure sensor and by feedback control.

LOCK-UP AND SELECT CONTROL SYSTEM

LOCK-UP AND SELECT CONTROL SYSTEM : System Diagram

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LOCK-UP AND SELECT CONTROL SYSTEM : System Description

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• The torque converter clutch piston in the torque converter is engaged to eliminate torque converter slip to

increase power transmission efficiency.

• The torque converter clutch control valve operation is controlled by the torque converter clutch solenoid

valve, which is controlled by a signal from TCM. The torque converter clutch control valve engages or
releases the torque converter clutch piston.

• When shifting between “N” (“P”) 

⇒

 “D” (“R”), torque converter clutch solenoid valve controls engagement

power of forward clutch and reverse brake.

• The lock-up applied gear range was expanded by locking up the

torque converter at a lower vehicle speed than conventional A/T
models.

• If the CVT fluid temperature is low or the vehicle is in fail-safe

mode due to malfunction, lock-up control is prohibited.

Lock-up Released

In the lock-up released state, the torque converter clutch control valve is set into the unlocked state by the
torque converter clutch solenoid valve and the lock-up apply pressure is drained.
In this way, the torque converter clutch piston is not coupled.

Lock-up Applied

In the lock-up applied state, the torque converter clutch control valve is set into the locked state by the torque
converter clutch solenoid valve and lock-up apply pressure is generated.
In this way, the torque converter clutch piston is pressed and coupled.

JSDIA1355GB

JPDIA0312GB

SYSTEM

TM-31

< SYSTEM DESCRIPTION >

[CVT: RE0F09B]

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Select Control

When shifting between “N” (“P”) 

⇒

 “D” (“R”), optimize the operating pressure on the basis of the throttle posi-

tion, the engine speed, and the secondary pulley (output) revolution speed to lessen the shift shock.

SHIFT CONTROL SYSTEM

SHIFT CONTROL SYSTEM : System Diagram

INFOID:0000000009650092

NOTE:
The gear ratio is set for each position separately.

SHIFT CONTROL SYSTEM : System Description

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In order to select the gear ratio that can obtain the driving force in accordance with driver's intention and the
vehicle condition, TCM monitors the driving conditions, such as the vehicle speed and the throttle position,
selects the optimum gear ratio, and determines the gear change steps to the gear ratio. Then TCM sends the
command to the step motor, controls the inflow/outflow of line pressure from the primary pulley to determine
the position of the moving-pulley and controls the gear ratio.

“D” POSITION

Shifting over all the ranges of gear ratios from the lowest to the high-
est.

OVERDRIVE OFF CONDITION

Use this position for improved engine braking.

“L” POSITION

JSDIA1356GB

SCIA1953E

JPDIA0685GB

TM-32

< SYSTEM DESCRIPTION >

[CVT: RE0F09B]

SYSTEM

By limiting the gear range to the lowest position, the strong driving
force and the engine brake can be secured.

DOWNHILL ENGINE BRAKE CONTROL (AUTO ENGINE BRAKE CONTROL)

When a downhill slope is detected with the accelerator pedal released, the engine brake will be strengthened
up by downshifting so as not to accelerate the vehicle more than necessary. 

ACCELERATION CONTROL

According to vehicle speed and a change of accelerator pedal angle, driver's request for acceleration and driv-
ing scene are judged. This function assists improvement in the acceleration feeling by making the engine
speed proportionate to the vehicle speed. And a shift map that can gain a larger driving force is available for
compatibility of mileage with driveability.

SHIFT LOCK SYSTEM

SHIFT LOCK SYSTEM : System Description

INFOID:0000000009650094

The selector lever cannot be shifted from the “P” position unless the
brake pedal is depressed while the ignition switch is set to ON. The
shift lock is unlocked by turning the shift lock solenoid ON when the
ignition switch is set to ON, the park position switch is turned ON
(selector lever is in “P” position), and the stop lamp switch is turned
ON (brake pedal is depressed) as shown in the operation chart in the
figure. Therefore, the shift lock solenoid receives no ON signal and
the shift lock remains locked if all of the above conditions are not ful-
filled. (However, selector operation is allowed if the shift lock release
button is pressed.)

SHIFT LOCK OPERATION AT “P” POSITION

When Brake Pedal Is Not Depressed (No Selector Operation Allowed)

JPDIA0686GB

JPDIA0624GB

SYSTEM

TM-33

< SYSTEM DESCRIPTION >

[CVT: RE0F09B]

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The shift lock solenoid (1) is turned OFF (not energized) and the
solenoid rod (A) is extended with the spring when the brake pedal is
not depressed (no selector operation allowed) with the ignition
switch ON.
The connecting lock lever (B) is located at the position shown in the
figure when the solenoid rod is extended. It prevents the movement
of the detent rod (C). For these reasons, the selector lever cannot be
shifted from the “P” position.

When Brake Pedal Is Depressed (Shift Operation Allowed)

The shift lock solenoid (1) is turned ON (energized) when the brake
pedal is depressed with the ignition switch ON. The solenoid rod (A)
is compressed by the electromagnetic force. The connecting lock
lever (B) rotates when the solenoid is activated. Therefore, the
detent rod (C) can be moved. For these reasons, the selector lever
can be shifted to other positions.

“P” POSITION HOLD MECHANISM (IGNITION SWITCH LOCK)

The shift lock solenoid (1) is not energized when the ignition switch
is in any position other than ON. In this condition, the shift mecha-
nism is locked and “P” position is held. The operation cannot be per-
formed from “P” position if the brake pedal is depressed with the
ignition switch ON when the operation system of shift lock solenoid is
malfunctioning. However, the lock lever (B) is forcibly rotated and the
shift lock is released when the shift lock release button (A) is
pressed from above. Then the selector operation from “P” position
can be performed.

CAUTION:

Use the shift lock release button only when the selector lever
cannot be operated even if the brake pedal is depressed with
the ignition switch ON.

JSDIA2161ZZ

JSDIA2162ZZ

JSDIA2163ZZ