Automatic Transmission: Overview Nissan Titan I

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 COMMUNICATION in CAN SYSTEM (INTRODUCTION) - TITAN article in ACCESSORIES & BODY, CAB. .

Scheme 23

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-170082-S01529061422005010600000) in Gauges & Instrument Panel - Titan article in ACCESSORIES & BODY, CAB. .
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.

Scheme 24

1. The road test inspects overall performance of the A/T and analyzes possible malfunction causes.
2. The road test is carried out in the following three stages.

1. Check before engine is started. Refer to «CHECK BEFORE ENGINE IS STARTED»(ref-169880-S11287239502004121700000) .
2. Check at idle. Refer to «CHECK AT IDLE»(ref-169880-S39727795492004121700000) .
3. Cruise test Inspect all the items from Part 1 to Part 3. Refer to «CRUISE TEST - PART 1»(ref-169880-S14400314092004121700000) , «CRUISE TEST - PART 2»(ref-169880-S34980846282004121700000) , and «CRUISE TEST - PART 3»(ref-169880-S06725629992004121700000) .

1. Before beginning the road test, check the test procedure and inspection items.
2. Test all inspection items until the symptom is uncovered. Diagnose NG items when all road tests are complete.

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

Scheme 25

The TCM consists of a microcomputer and connectors for signal input and output and for power supply. The TCM controls the A/T.

1. The park/neutral position (PNP) switch includes a transmission position switch.
2. The transmission range switch detects the selector lever position and sends a signal to the TCM.

Scheme 26

The revolution sensor detects the revolution of the idler gear parking pawl lock gear and emits a pulse signal. The pulse signal is sent to the TCM which converts it into vehicle speed.

Scheme 27

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

Scheme 28

1. The torque converter clutch solenoid valve is activated, with the gear in D4, D5 by the TCM in response to signals sent from the vehicle speed sensor and accelerator pedal position sensor (throttle position sensor). Torque converter clutch piston operation will then be controlled.
2. Lock-up operation, however, is prohibited when A/T fluid temperature is too low.
3. When the accelerator pedal is depressed (less than 1/8) 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.

Scheme 29

This malfunction is detected when the A/T does not shift into 5th gear position or 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.

Scheme 30

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

The line pressure duty cycle value is not consistent when the closed throttle position signal is "ON".

To confirm the line pressure duty cycle at low pressure, the accelerator (throttle) should be open until the closed throttle position signal is "OFF".

Scheme 31

The TCM consists of a microcomputer and connectors for signal input and output and for power supply. The TCM controls the A/T.

The TCM consists of a microcomputer and connectors for signal input and output and for power supply. The TCM controls the A/T.

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 signals to TCM with CAN communication.

The A/T fluid temperature sensor detects the A/T fluid temperature and sends a signal to the TCM.

Scheme 32

The turbine revolution sensor detects input shaft rpm (revolutions per minute). It is located on the input side of the automatic transmission. Monitors revolution of sensor 1 and sensor 2 for non-standard conditions.

Scheme 33

The vehicle speed sensor.MTR signal is transmitted from combination meter to TCM by CAN communication line. The signal functions as an auxiliary device to the revolution sensor when it is malfunctioning. The TCM will then use the vehicle speed sensor.MTR signal.

Scheme 34

1. Fail-safe function to detect interlock conditions.

Fail-safe function to prevent sudden decrease in speed by engine brake other than at 1 or M 1 position.

Scheme 35

Input clutch solenoid valve is controlled by the TCM in response to signals sent from the PNP switch, vehicle speed sensor and accelerator pedal position sensor (throttle position sensor). Gears will then be shifted to the optimum position.

Scheme 36

1. Input clutch solenoid valve is controlled by the TCM in response to signals sent from the PNP switch, vehicle speed sensor and accelerator pedal position sensor (throttle position sensor). Gears will then be shifted to the optimum position.
2. 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.

Scheme 37

Front brake solenoid valve is controlled by the TCM in response to signals sent from the PNP switch, vehicle speed sensor and accelerator pedal position sensor (throttle position sensor). Gears will then be shifted to the optimum position.

Scheme 38

1. Front brake solenoid valve is controlled by the TCM in response to signals sent from the PNP switch, vehicle speed sensor and accelerator pedal position sensor (throttle position sensor). Gears will then be shifted to the optimum position.
2. 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.

Scheme 39

Direct clutch solenoid valve is controlled by the TCM in response to signals sent from the PNP switch, vehicle speed sensor and accelerator pedal position sensor (throttle position sensor). Gears will then be shifted to the optimum position.

Scheme 40

1. Direct clutch solenoid valve is controlled by the TCM in response to signals sent from the PNP switch, vehicle speed sensor and accelerator pedal position sensor (throttle position sensor). Gears will then be shifted to the optimum position.
2. 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.

Scheme 41

High & low reverse clutch solenoid valve is controlled by the TCM in response to signals sent from the PNP switch, vehicle speed sensor and accelerator pedal position sensor (throttle position sensor). Gears will then be shifted to the optimum position.

Scheme 42

1. High & low reverse clutch solenoid valve is controlled by the TCM in response to signals sent from the PNP switch, vehicle speed sensor and accelerator pedal position sensor (throttle position sensor). Gears will then be shifted to the optimum position.
2. 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.

Scheme 43

Low coast brake solenoid valve is turned "ON" or "OFF" by the TCM in response to signals sent from the PNP switch, vehicle speed sensor and accelerator pedal position sensor (throttle position sensor). Gears will then be shifted to the optimum position.

Scheme 44

1. Low coast brake solenoid valve is turned "ON" or "OFF" by the TCM in response to signals sent from the PNP switch, vehicle speed sensor and accelerator pedal position sensor (throttle position sensor). Gears will then be shifted to the optimum position.
2. 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.

Scheme 45

When an impossible pattern of switch signals is detected, this is judged to be an irregularity.

Scheme 46

Fail-safe function to detect front brake clutch solenoid valve condition.

Scheme 47

Fail-safe function to detect input clutch solenoid valve condition.

Scheme 48

Fail-safe function to detect direct clutch solenoid valve condition.

Scheme 49

Fail-safe function to detect high & low reverse clutch solenoid valve condition.

Scheme 50

When tow mode switch is ON, tow mode switch signals are sent to TCM from combination meter by CAN communication. Then the A/T is in tow mode condition.