Automatic Transaxle - RE4F04B: Overview Nissan Sentra B15

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.

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Conditions for Lock-up Operation

When vehicle is driven in 3rd and 4th gear position, vehicle speed and throttle opening are detected. If the detected values fall within the lock-up zone memorized in the TCM, lock-up occurs.

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Overrun Clutch Control Valve Operation

When the solenoid valve is ON, pilot pressure is applied to the overrun clutch control valve. This pushes up the overrun clutch control valve. The line pressure is then shut off so that the clutch does not engage.

When the solenoid valve is OFF, pilot pressure is not generated. At this point, the overrun clutch control valve moves downward by spring force. As a result, overrun clutch operation pressure is provided by the overrun clutch reducing valve. This causes the overrun clutch to engage.

In the 1 position, the overrun clutch control valve remains pushed down so that the overrun clutch is engaged at all times.

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DESCRIPTION

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

1. Check before engine is started
2. Check at idle
3. Cruise test

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1. Before road test, familiarize yourself with all test procedures and items to check.
2. Conduct tests on all items until specified symptom is found. Troubleshoot items which check out No Good after road test. Refer to " «ON BOARD DIAGNOSTIC SYSTEM DESCRIPTION»(ref-214137-S21926015672005123100000) " and " «TROUBLE DIAGNOSIS FOR SYMPTOMS»(ref-214137-S18443319062005123100000) ".

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1. CHECK O/D OFF INDICATOR LAMP Park vehicle on flat surface. Move selector lever to P position. Turn ignition switch to OFF position. Wait at least 5 seconds. Turn ignition switch to ON position. (Do not start engine.) Does O/D OFF indicator lamp come on for about 2 seconds? Yes or No Yes: GO TO 2. No: Stop ROAD TEST. Go to " «1. O/D OFF INDICATOR LAMP DOES NOT COME ON»(ref-214137-S19247865832005123100000) ".
2. CHECK O/D OFF INDICATOR LAMP Does O/D OFF indicator lamp flicker for about 8 seconds? Yes or No Yes: TCM is in fail-safe mode. Perform self-diagnosis and check NG items on the «DIAGNOSTIC WORKSHEET»(ref-214137-S28625481542005123100000) , . Refer to " «TCM SELF-DIAGNOSTIC PROCEDURE (NO TOOLS)»(ref-214137-S13340352232005123100000) ". No: Turn ignition switch to OFF position. Perform self-diagnosis and note NG items. Refer to " «TCM SELF-DIAGNOSTIC PROCEDURE (NO TOOLS)»(ref-214137-S13340352232005123100000) ". Go to " «2. CHECK AT IDLE»(ref-214137-S21749398842005123100000) ".

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1. CHECK ENGINE START Park vehicle on flat surface. Move selector lever to P position. Turn ignition switch to OFF position. Turn ignition switch to START position. Is engine started? Yes or No Yes: Stop ROAD TEST. No: Mark the box on the DIAGNOSTIC WORKSHEET. Go to " «2. ENGINE CANNOT BE STARTED IN P AND N POSITION»(ref-214137-S38644261582005123100000) ".
2. CHECK ENGINE START Turn ignition switch to ACC position. Move selector lever to D, 1, 2 or R position. Turn ignition switch to START position. Is engine started? Yes or No Yes: Stop ROAD TEST. Mark the box on the DIAGNOSTIC WORKSHEET. Go to " «2. ENGINE CANNOT BE STARTED IN P AND N POSITION»(ref-214137-S38644261582005123100000) ". No: GO TO 3.
3. CHECK VEHICLE MOVE Move selector lever to P position. Turn ignition switch to OFF position. Release parking brake. Push vehicle forward or backward. Does vehicle move when it is pushed forward or backward? Apply parking brake. Yes or No Yes: Mark the box on the DIAGNOSTIC WORKSHEET. Go to " «3. IN P POSITION, VEHICLE MOVES FORWARD OR BACKWARD WHEN PUSHED»(ref-214137-S00972428292005123100000) ". Continue ROAD TEST. No: GO TO 4.
4. CHECK VEHICLE MOVE Start engine. Move selector lever to N position. Release parking brake. Does vehicle move forward or backward? Yes or No Yes: Mark the box on the DIAGNOSTIC WORKSHEET. Go to " «4. IN N POSITION, VEHICLE MOVES»(ref-214137-S11770939782005123100000) ". Continue ROAD TEST. No: GO TO 5.
5. CHECK SHIFT LOCK Apply foot brake. Move selector lever to R position. Is there large shock when changing from N to R position? Yes or No Yes: Mark the box on the DIAGNOSTIC WORKSHEET. Go to " «5. Large Shock N --> R Position»(ref-214137-S39751511522005123100000) ". Continue ROAD TEST. No: GO TO 6.
6. CHECK VEHICLE MOVE Release foot brake for several seconds. Does vehicle creep backward when foot brake is released? Yes or No Yes: GO TO 7. No: Mark the box on the DIAGNOSTIC WORKSHEET. Go to " «6. VEHICLE DOES NOT CREEP BACKWARD IN R POSITION»(ref-214137-S20655212972005123100000) ". Continue ROAD TEST.
7. CHECK VEHICLE MOVE Move selector lever to D, 2 and 1 positions and check if vehicle creeps forward. Does vehicle creep forward in all three positions? Yes or No Yes: Go to " «3. CRUISE TEST»(ref-214137-S39082676092005123100000) ". No: Mark the box on the DIAGNOSTIC WORKSHEET. Go to " «7. VEHICLE DOES NOT CREEP FORWARD IN D, 2 OR 1 POSITION»(ref-214137-S04236641882005123100000) ". Continue ROAD TEST.

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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.

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

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

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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.

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

1. This malfunction will not be detected while the O/D OFF indicator lamp is indicating another self-diagnosis malfunction.
2. This malfunction is detected when the A/T does not shift into first gear position as instructed by the TCM. This is not caused by electrical malfunction (circuits open or shorted) but by mechanical malfunction such as control valve sticking, improper solenoid valve operation, etc.

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1. This malfunction will not be detected while the O/D OFF indicator lamp is indicating another self-diagnosis malfunction.
2. This malfunction is detected when the A/T does not shift into second gear position as instructed by the TCM. This is not caused by electrical malfunction (circuits open or shorted) but by mechanical malfunction such as control valve sticking, improper solenoid valve operation, etc.

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1. This malfunction will not be detected while the O/D OFF indicator lamp is indicating another self-diagnosis malfunction.
2. This malfunction is detected when the A/T does not shift into third gear position as instructed by the TCM. This is not caused by electrical malfunction (circuits open or shorted) but by mechanical malfunction such as control valve sticking, improper solenoid valve operation, malfunctioning servo piston or brake band, etc.

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1. This malfunction will not be detected while the O/D OFF indicator lamp is indicating another self-diagnosis malfunction.
2. This malfunction is detected when the A/T does not shift into fourth gear position as instructed by the TCM, or if the line pressure is low. This is not caused by electrical malfunction (circuits open or shorted) but by mechanical malfunction such as control valve sticking, improper solenoid valve operation, malfunctioning oil pump or torque converter clutch, etc.

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The torque converter clutch solenoid valve is activated, with the gear in D4, by the TCM in response to signals sent from the vehicle speed and the ECM (throttle opening). Lock-up piston operation will then be controlled.

Lock-up operation, however, is prohibited when A/T fluid temperature is too low.

When the accelerator pedal is depressed (less than 2/8) 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.

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1. This is an OBD-II self-diagnostic item and not available in TCM self-diagnosis.
2. This malfunction will not be detected while the O/D OFF indicator lamp is indicating another self-diagnosis malfunction.
3. This malfunction is detected when the A/T does not shift into fourth gear position or the torque converter clutch does not lock up as instructed by the TCM. This is not caused by electrical malfunction (circuits open or shorted) but by mechanical malfunction such as control valve sticking, improper solenoid valve operation, malfunctioning oil pump or torque converter clutch, etc.

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.

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Shift solenoid valves A and B are turned ON or OFF by the TCM in response to signals sent from the park/neutral position (PNP) switch, vehicle speed and ECM (throttle opening). Gears will then be shifted to the optimum position.

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Shift solenoid valves A and B are turned ON or OFF by the TCM in response to signals sent from the park/neutral position (PNP) switch, vehicle speed and ECM (throttle opening). Gears will then be shifted to the optimum position.

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The throttle position sensor [accelerator pedal position (APP) sensor] is part of the system that controls throttle position. This system also uses an electric throttle control actuator which consists of a throttle control motor and throttle position sensors. Accelerator pedal position signal is sent to the ECM.

The overrun clutch solenoid valve is activated by the TCM in response to signals sent from the park/neutral position (PNP) switch, overdrive control switch, vehicle speed and ECM (throttle opening). The overrun clutch operation will then be controlled.

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

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The vehicle speed sensor MTR is built into the speedometer assembly. The sensor functions as an auxiliary device to the revolution sensor when it is malfunctioning. The TCM will then use a signal sent from the vehicle speed sensor MTR.

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The turbine revolution sensor detects input shaft rpm (revolutions per minute). It is located on the input side of the automatic transaxle. The vehicle speed sensor A/T (Revolution sensor) is located on the output side of the automatic transaxle. With the two sensors, input and output shaft RPM are accurately detected. The result is optimal shift timing during deceleration and improved shifting.

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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.

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

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

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ON BOARD DIAGNOSIS LOGIC

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1. The mechanical key interlock mechanism also operates as a shift lock: With the key switch turned to ON, the selector lever cannot be shifted from "P" (parking) to any other position unless the brake pedal is depressed. With the key removed, the selector lever cannot be shifted from "P" to any other position. The key cannot be removed unless the selector lever is placed in "P".
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 the key cylinder.

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