Continuously Variable Transmission (Cvt): Overview Nissan Versa I

OPERATION PROCEDURE

1. Connect both battery cables. NOTE: Supply power using jumper cables if battery is discharged.
2. Use the Intelligent Key or mechanical key to turn the ignition switch to the "ACC" position. At this time, the steering lock will be released.
3. Disconnect both battery cables. The steering lock will remain released and the steering wheel can be rotated.
4. Perform the necessary repair operation.
5. When the repair work is completed, return the ignition switch to the "LOCK" position before connecting the battery cables. (At this time, the steering lock mechanism will engage.)
6. Perform a self-diagnosis check of all control units using CONSULT-III.

SYSTEM 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 error 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 independent). 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. For details, refer to " CAN SYSTEM SPECIFICATION CHART ".

DESCRIPTION

The MIL is located on the instrument panel.

1. The MIL will light up when the ignition switch is turned ON without the engine running. This is a bulb check. If the MIL does not light up, refer to " «WARNING LAMPS»(ref-337635-S11202846792009080600000) " or " «MIL AND DATA LINK CONNECTOR»(ref-319464-S15201515562009062600000) ".
2. When the engine is started, the MIL should go off. If the MIL remains on, the on board diagnostic system has detected an engine system malfunction.

1. The purpose of the test is to determine overall performance of CVT and analyze causes of problems.
2. The road test consists of the following three parts

Scheme 1

1. "Check Before Engine Is Started" «CHECK BEFORE ENGINE IS STARTED»(ref-337628-S21087125822009080600000) .
2. "Check at Idle" «CHECK BEFORE ENGINE IS STARTED»(ref-337628-S21087125822009080600000) .
3. "Cruise Test" «CRUISE TEST»(ref-337628-S15635354662009080600000) .

Scheme 2

1. Before road test, familiarize yourself with all test procedures and items to check.
2. Perform tests on all items until specified symptom is found. Troubleshoot items which check out No Good after road test.

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 independent). 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.

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 independent). 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.

1. TCM controls starter relay in IPDM E/R.
2. TCM switches starter relay ON at "P" or "N" position and allows to crank engine.
3. Then it prohibits cranking other than at "P" or "N" position.

ON, OFF status of the stop lamp switch is sent via the CAN communication from the combination meter to TCM using the signal.

1. The PNP switch is included in the control valve assembly.
2. The PNP switch includes 4 transmission position switches.
3. TCM judges the selector lever position by the PNP switch signal.

PARK/NEUTRAL POSITION SWITCH SPECIFICATION

1. The CVT fluid temperature sensor is included in the control valve assembly.
2. The CVT fluid temperature sensor detects the CVT fluid temperature and sends a signal to the TCM.

1. The input speed sensor (primary speed sensor) is included in the control valve assembly.
2. The input speed sensor (primary speed sensor) detects the primary pulley revolution speed and sends a signal to the TCM.

The vehicle speed sensor CVT [output speed sensor (secondary speed sensor)] detects the revolution of the CVT output shaft and emits a pulse signal. The pulse signal is sent to the TCM, which converts it into vehicle speed.

The engine speed signal is sent from the ECM to the TCM.

TCM selects the gear ratio using the engine load (throttle position), the primary pulley revolution speed, and the secondary pulley revolution speed as input signal. Then it changes the operating pressure of the primary pulley and the secondary pulley and changes the groove width of the pulley.

1. The torque converter clutch solenoid valve is included in the control valve assembly.
2. The torque converter clutch solenoid valve is activated by the TCM in response to signals sent from the vehicle speed and accelerator pedal position sensors. Lock-up piston operation will then be controlled.
3. Lock-up operation, however, is prohibited when CVT fluid temperature is too low.
4. When the accelerator pedal is depressed (less than 2.0/8) in lock up condition, the engine speed should not change abruptly. If there is a big jump in engine speed, there is no lock up.

1. The torque converter clutch solenoid valve is included in the control valve assembly.
2. This malfunction is detected when the torque converter clutch does not lock up as instructed by the TCM. This is not only caused by electrical malfunction (circuits open or shorted), but also by mechanical malfunction such as control valve sticking, improper solenoid valve operation, etc.

1. The pressure control solenoid valve A (line pressure solenoid valve) in included in the control valve assembly.
2. The pressure control solenoid valve A (line pressure solenoid valve) regulates the oil pump discharge pressure to suit the driving condition in response to a signal sent from the TCM.

1. The pressure control solenoid valve A (line pressure solenoid valve) are included in the control valve assembly.
2. The pressure control solenoid valve A (line pressure solenoid valve) regulates the oil pump discharge pressure to suit the driving condition in response to a signal sent from the TCM.

1. The pressure control solenoid valve B (secondary pressure solenoid valve) is included in the control valve assembly.
2. The pressure control solenoid valve B (secondary pressure solenoid valve) regulates the secondary pressure to suit the driving condition in response to a signal sent from the TCM.

1. The pressure control solenoid valve B (secondary pressure solenoid valve) is included in the control valve assembly.
2. The pressure control solenoid valve B (secondary pressure solenoid valve) regulates the oil pump discharge pressure to suit the driving condition in response to a signal sent from the TCM.

1. The transmission fluid pressure sensor A (secondary pressure sensor) is included in the control valve assembly.
2. The transmission fluid pressure sensor A (secondary pressure sensor) detects secondary pressure of CVT and sends TCM the signal.

Using the engine load (throttle position), the primary pulley revolution speed, and the secondary pulley revolution speed as input signal, TCM changes the operating pressure of the primary pulley and the secondary pulley and changes the groove width of the pulley to control the gear ratio.

1. The transmission fluid pressure sensor B (primary pressure sensor) is included in the control valve assembly.
2. The transmission fluid pressure sensor B (primary pressure sensor) detects primary pressure of CVT and sends TCM the signal.

1. The pressure control solenoid valve B (secondary pressure solenoid valve) is included in the control valve assembly.
2. The pressure control solenoid valve B (secondary pressure solenoid valve) regulates the secondary pressure to suit the driving condition in response to a signal sent from the TCM.

When the power supply to the TCM is cut OFF, for example because the battery is removed, and the self-diagnosis memory function stops, malfunction is detected.

Note. Since "P1701 TCM-POWER SUPPLY" will be indicated when replacing TCM, perform diagnosis after erasing "SELF-DIAG RESULTS"

Electric throttle control actuator consists of throttle control motor, accelerator pedal position sensor, throttle position sensor etc. The actuator sends a signal to the ECM, and ECM sends the signal to TCM with CAN communication.

The vehicle speed signal is transmitted from ABS actuator and electric unit (control unit) to TCM by CAN communication line.

1. The input speed sensor (primary speed sensor) is included in the control valve assembly.
2. The vehicle speed sensor CVT [output speed sensor (secondary speed sensor)] detects the revolution of the parking gear and generates a pulse signal. The pulse signal is sent to the TCM, which converts it into vehicle speed.
3. The input speed sensor (primary speed sensor) detects the primary pulley revolution speed and sends a signal to the TCM.

Electric throttle control actuator consists of throttle control motor, accelerator pedal position sensor, throttle position sensor etc. The actuator sends a signal to the ECM, and ECM sends the signal to TCM with CAN communication.

1. The lock up select solenoid valve is included in the control valve assembly.
2. The lock up select solenoid valve controls lock up clutch pressure or forward clutch pressure (reverse brake pressure).
3. When controlling lock up clutch, the valve is turned OFF. When controlling forward clutch, it is turned ON.

The pressure control solenoid valve A (line pressure solenoid valve) regulates the oil pump discharge pressure to suit the driving condition in response to a signal sent from the TCM.

1. The step motor is included in the control valve assembly.
2. The step motor changes the step with turning 4 coils ON/OFF according to the signal from TCM. As a result, the flow of line pressure to primary pulley is changed and pulley ratio is controlled

1. The step motor is included in the control valve assembly.
2. The step motor's 4 aspects of ON/OFF change according to the signal from TCM. As a result, the flow of line pressure to primary pulley is changed and pulley ratio is controlled.
3. This diagnosis item is detected when electrical system is OK, but mechanical system is NG.
4. This diagnosis item is detected when the state of the changing the speed mechanism in unit does not operate normally.

1. Overdrive control switch is installed to the selector lever.
2. O/D OFF indicator turns ON, and overdrive driving activates when pressing the overdrive control switch while driving in "D" position. O/D OFF indicator turns OFF, and "D" position driving starts when pressing the overdrive control switch while driving in the overdrive-off mode. Shifting the selector lever in any position other than "D" releases the overdrive-off mode.

TCM sends the switch signals to combination meter via CAN communication line. Then selector lever position is indicated on the shift position indicator.

1. The mechanical key interlock mechanism also operates as a shift lock: With the ignition switch turned to ON, selector lever cannot be shifted from "P" position to any other position unless brake pedal is depressed. With the key removed, selector lever cannot be shifted from "P" position to any other position. The key cannot be removed unless selector lever is placed in "P" position.
2. The shift lock and key interlock mechanisms are controlled by the ON-OFF operation of the shift lock solenoid and by the operation of the rotator and slider located inside key cylinder, respectively.

Scheme 3