Automatic Transmission (Cvt): Overview Nissan Rogue II

COMPONENT DESCRIPTION

Scheme 1

TRANSAXLE: Operation Status

TRANSAXLE: Component Description

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CVT Oil Warmer

Scheme 3

1. The CVT oil warmer (1) is installed on the front part of transaxle assembly.
2. When engine is started while engine and CVT are cold, engine coolant temperature rises more quickly than CVT fluid temperature. CVT oil warmer is provided with two circuits for CVT and engine coolant respectively so that warmed engine coolant warms CVT quickly. This helps shorten CVT warming up time, improving fuel economy.
3. A cooling effect is obtained when CVT fluid temperature is high.

Heater Thermostat

Scheme 4

1. The heater thermostat (1) is installed on the front part of transaxle assembly.
2. The heater thermostat open and close with set temperature.

CVT Fluid Cooler (Water Cooling Type)

Scheme 5

1. The CVT fluid cooler (water cooling type) (1) is installed in the lower part of radiator.
2. CVT fluid is cooled by engine coolant to flow through the radiator.

SHIFT LOCK SYSTEM: System Description

1. The shift lock system prevents the select lever from being moved from "P" position to other positions due to a driver's improper operation and prevents the occurrence of an abrupt start.
2. Shift lock can be released when the following conditions are satisfied. Ignition switch is ON. Brake pedal is depressed. (Stop lamp switch is ON)

SHIFT LOCK OPERATION AT P POSITION

When brake pedal is not depressed (no selector operation allowed)

When the brake pedal is not depressed with the ignition switch ON, the shift lock solenoid (A) is OFF (not energized) and the solenoid rod (B) is extended with spring.

The connecting lock lever (C) is located at the position shown in the figure below when the solenoid rod is extended. It prevents the movement of the detent rod (D). The selector lever cannot be shifted from the "P" position for this reason.

Scheme 6

When brake pedal is depressed (selector lever operation allowed)

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

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1. When battery voltage decreases or an electrical/mechanical malfunction occurs in the shift lock system, the selector lever cannot be operated in "P" position. When shift lock release rod (A) is pressed in this state, lock lever (B) is forcibly rotated, and then it becomes possible to release shift lock.
2. To release the shift lock forcibly and shift the selector lever from "P" position to other positions, follow the steps below. Turn ignition switch OFF. Apply parking brake. Press the shift lock release button (1) with suitable tool. Press and hold the selector lever knob button and move the selector lever from "P" position to other positions while press the shift lock release button.

DESCRIPTION

Highly accurate line pressure control and secondary pressure control reduces friction for improvement of fuel economy.

Normal Oil Pressure Control

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, vehicle speed, input torque, stop lamp switch signal, transmission range switch signal, lock-up signal, power voltage, target shift ratio, oil temperature, oil pressure, and overdrive control switch signal.

Secondary Pressure Feedback Control

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

Scheme 10

To select the gear ratio that can give the driving force to meet driver's intent or vehicle situation, the vehicle driving condition such as vehicle speed or accelerator pedal position is detected and the most appropriate gear ratio is selected and the shifting method before reaching the speed is determined. The information is output to the primary pressure solenoid valve and secondary pressure solenoid valve to control the line pressure input/output to the pulley, to determine the pulley (movable pulley) position and to control the gear position.

Shift Position Function

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1. D Position (Normal) Gear shifting is performed in all shifting ranges from the lowest to the highest gear ratio.
2. D Position (O/D OFF) The gear ratio is generally high by limiting the shifting range on the high side, and this always generates a large driving power.
3. L Position By limiting the shifting range only to the lowest of the gear ratio, a large driving force and engine brake are obtained.

Hill Climbing And Descending Control

If a downhill is detected with the accelerator pedal is released, the system performs downshift to increase the engine brake force so that vehicle may not be accelerated more than necessary. If a climbing hill is detected, the system improves the acceleration performance in re-acceleration by limiting the gear shift range on the high side.

Note. For engine brake control on a downhill, the control can be stopped with CONSULT.

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Control In Acceleration

From change of the vehicle speed or accelerator pedal position, the acceleration request level of the driver or driving scene is evaluated. In start or acceleration during driving, the gear shift characteristics with linearity of revolution increase and vehicle speed increase are gained to improve the acceleration feel.

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1. When the accelerator pedal is depressed 4/8 or more in D position, CVT performs step shifting to allow the vehicle speed and engine speed to increase simultaneously. This improves the feel of acceleration and enables the fuel economy by preventing unnecessary rise in engine speed, compared to the conventional shifting.

Scheme 16

Based on accelerator pedal angle, engine speed, primary pulley speed, and the input speed, the optimum operating pressure is set to reduce impact of a selector lever operation while shifting from "N" ("P") to "D" ("R") position.

Scheme 17

1. Controls for improvement of the transmission efficiency by engaging the torque converter clutch in the torque converter and eliminating slip of the converter. Achieves comfortable driving with slip control of the torque converter clutch.
2. The oil pressure feed circuit for the torque converter clutch piston chamber is connected to the torque converter clutch control valve. The torque converter clutch control valve is switched by the torque converter clutch solenoid valve with the signal from TCM. This controls the oil pressure circuit, which is supplied to the torque converter clutch piston chamber, to the release side or engagement side.
3. 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 engagement

In lock-up engagement, the torque converter clutch solenoid valve makes the torque converter clutch control valve locked up to generate the lock-up apply pressure. This pushes the torque converter clutch piston for engagement.

Lock-up release condition

In lock-up release, the torque converter clutch solenoid valve makes the torque converter clutch control valve non-locked up to drain the lock-up apply pressure. This does not engage the torque converter clutch piston.

Scheme 18

1. For a sporty driving on winding roads, establishing sport mode allows the driver to perform a sporty driving different from normal driving performed in D position.
2. If overdrive control switch is operated during SPORT mode ON condition, overdrive control operation will take priority.

Sport Mode Function

High Gear Ratio Limit

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1. Engine speed is kept higher than at D position driving, which helps to operate a "sporty" driving.

Step Shift

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1. Pressing down the accelerator pedal allows to drive the vehicle with a feeling of A/T-like gear shifting.

Braking Down Shift

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1. At a moderate braking operation before corner etc., the engine speed increases according to the deceleration and the transmission shifts down automatically, in order to optimize the response at reacceleration while providing an adequate engine braking.

Acceleration Off Ratio Hold

1. When the vehicle is decelerated by quickly releasing the foot from accelerator pedal, transmission does not shift up automatically to keep a constant gear ratio, holding the high engine speed. When the vehicle is decelerated (by accelerator pedal OFF) in upper area of double line in below chart, the engine speed shows a characteristic like "A". On the other hand, when the vehicle is decelerated (by accelerator pedal OFF) in lower area of double line in below chart, the engine speed shows a characteristic like "B".

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Fail-Safe

If a malfunction occurs in CVT system during SPORT mode ON, SPORT mode indicator extinguishes and the vehicle returns to standard D position driving.

Diagnosis Description

This system is an on board diagnostic system that records exhaust emission-related diagnostic information and detects a sensors/actuator-related malfunction. A malfunction is indicated by the malfunction indicator lamp (MIL) and stored in ECU memory as a DTC. The diagnostic information can be obtained with the diagnostic tool (GST: Generic Scan Tool).

DIAGNOSIS DESCRIPTION: 1 Trip Detection Diagnosis and 2 Trip Detection Diagnosis

Note. "Start the engine and turn OFF the ignition switch after warm-up." This is defined as 1 trip.

DIAGNOSIS DESCRIPTION: Malfunction Indicator Lamp (MIL)

1. TCM not only detects DTC, but also sends the MIL signal to ECM through CAN communication. ECM sends the MIL signal to the combination meter through CAN communication according to the signal, and illuminates MIL.
2. For malfunction indicator lamp (MIL) description, refer to " «WARNING/INDICATOR/CHIME LIST: MALFUNCTION INDICATOR LAMP (MIL)»(ref-616720-S00009018092014051900000) ".

There are many operating conditions that may cause a malfunction of the transmission parts. By understanding those conditions properly, a quick and exact diagnosis can be achieved.

In general, perception of a problem varies depending on individuals. Ask the customer about his/her concerns carefully. It is important to understand the phenomenon or status. To systemize all the information for the diagnosis, prepare the question sheet referring to the question points.

In some cases, multiple conditions that appear simultaneously may cause a DTC to be detected.

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Always perform the following items when the TCM is replaced.

TCM PROGRAMMING

1. Since vehicle specifications are not yet written in a new TCM, it is necessary to write them with CONSULT.

SAVING AND WRITING OF TCM DATA

1. TCM performs accurate control by retrieving data (inherent characteristic value) of each solenoid. For this reason, it is necessary to save data of current TCM in CONSULT before replacing the TCM. After this, the saved data must be written in new TCM.

Perform the following work after the transaxle assembly is replaced.

WRITING TCM DATA

1. TCM performs accurate control by retrieving data (inherent characteristic value) of each solenoid. For this reason, after replacing transaxle assembly, it is necessary to write new data in TCM.

ERASING OF CVT FLUID DEGRADATION LEVEL DATA

1. TCM records the degradation level of the CVT fluid calculated from the vehicle driving status. Therefore, if the transaxle assembly is replaced, it is necessary to erase the CVT fluid degradation level data recorded by TCM.

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1. CHECK THE SERIAL NUMBER Write down the serial number of new transaxle assembly. : GO TO 2.
2. WRITE TCM DATA (IP CHARACTERISTICS VALUE) NOTE: Write data of new solenoid in TCM according to the following instructions: With CONSULT CAUTION: When the work is interrupted, obtain data again from the supplied CD. Shift the selector lever to the P position. Turn ignition switch OFF and wait for 10 seconds. Turn ignition switch ON. Insert the supplied CD into CONSULT. Select "Work Support" in "TRANSMISSION". Select "WRITE IP CHARA - REPLACEMENT AT/CVT". Check that the serial number displayed on CONSULT screen and those written in the memo agree. Write data in TCM according to the instructions on the CONSULT screen. NOTE: When writing is complete, the shift position indicator of the combination meter displays P. : GO TO 3.
3. ERASE CVT FLUID DEGRADATION LEVEL DATA With CONSULT Select "WORK SUPPORT" in "TRANSMISSION". Select "CONFORM CVTF DETERIORTN". Touch "Clear". : WORK END

When replacing TCM and transaxle assembly simultaneously, perform the following work.

TCM PROGRAMMING

1. Since vehicle specifications are not yet written in a new TCM, it is necessary to write them with CONSULT.

WRITING TCM DATA

1. TCM performs accurate control by retrieving data (inherent characteristic value) of each solenoid. For this reason, after replacing TCM and transaxle assembly, it is necessary to write new data in TCM.

Permanent DTC can be erased by driving each driving pattern.

ECM recognizes each driving pattern; it transmits signals to each control module when the driving is complete. Each control module erases permanent DTC based on those signals. For details, refer to " DESCRIPTION ".

CAN (Controller Area Network) is a serial communication line for real-time application. It is an on-vehicle multiplex communication line with high data communication speed and excellent malfunction detection ability. Many electronic control units are equipped onto a vehicle, and each control unit shares information and links with other control units during operation (not independently). In CAN communication, control units are connected with 2 communication lines (CAN-H line, CAN-L line) allowing a high rate of information transmission with less wiring. Each control unit transmits/receives data but selectively reads required data only.

DTC Description

CAN (Controller Area Network) is a serial communication line for real-time application. It is an on-vehicle multiplex communication line with high data communication speed and excellent malfunction detection ability. Many electronic control units are equipped onto a vehicle, and each control unit shares information and links with other control units during operation (not independently). In CAN communication, control units are connected with 2 communication lines (CAN-H line, CAN-L line) allowing a high rate of information transmission with less wiring. Each control unit transmits/receives data but selectively reads required data only.

TCM compares the calculated value stored in the flash ROM with the value stored in TCM. If the calculated value does not agree with the stored value, TCM judges this as a malfunction.

TCM compares the calculated value stored in the flash ROM with the value stored in TCM. If the calculated value does not agree with the stored value, TCM judges this as a malfunction.

Replace the O-ring if oil leakage or exudes from the plug.

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