Nissan Pathfinder (2012 year). Instruction — part 181
4WD SYSTEM
DLN-13
< SYSTEM DESCRIPTION >
[TRANSFER: ATX14B]
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SYSTEM DESCRIPTION
4WD SYSTEM
System Diagram
INFOID:0000000007357348
COMPONENT DESCRIPTION
WDIA0164E
Components
Function
Transfer control unit
Controls transfer control device, control valves and shifts between 2WD/4WD and 4H/4LO.
Transfer control device
Integrates actuator motor and actuator position switch.
2-4WD shift solenoid valve
Controls oil pressure and allows shifting between 2WD and 4WD.
Clutch pressure solenoid valve
Controls oil pressure and distributes torque between front and rear tires.
Line pressure switch
Detects line pressure.
Clutch pressure switch
Detects clutch pressure.
Transfer fluid temperature sensor Detects transfer fluid temperature.
Actuator motor
Moves shift rods when signaled by transfer control unit.
Actuator position switch
Detects actuator motor position.
Wait detection switch
Detects whether or not 4WD lock gear is locked.
4LO switch
Detects if transfer case is in 4LO.
ATP switch
Detects if transfer case is in neutral.
4WD shift switch
Allows driver to select from 2WD/4WD, 4H/4LO and AUTO.
4WD warning lamp
• Illuminates if malfunction is detected in 4WD system.
• Flashes (1 flash / 2 seconds) if large difference in diameter of front and rear tires.
• Flashes (2 flashes / 1 second) if high transfer fluid temperature is detected.
ATP warning lamp
Indicates that A/T parking mechanism does not operate when A/T selector lever is in P position
because transfer case is in neutral.
4WD shift indicator lamp
Displays driving range selected by 4WD shift switch.
4LO indicator lamp
Displays 4LO range.
August 2012
2012 Pathfinder
DLN-14
< SYSTEM DESCRIPTION >
[TRANSFER: ATX14B]
4WD SYSTEM
System Description
INFOID:0000000007357349
CONTROL SYSTEM
ABS actuator and electric unit
(control unit)
Transmits vehicle speed signal via CAN communication to transfer control unit.
TCM
Transmits the following signal via CAN communication to transfer control unit.
• Output shaft revolution signal
• A/T position indicator signal (transmission range switch signal)
ECM
Transmits the following signals via CAN communication to transfer control unit.
• Engine speed signal
• Accelerator pedal position signal
Components
Function
August 2012
2012 Pathfinder
4WD SYSTEM
DLN-15
< SYSTEM DESCRIPTION >
[TRANSFER: ATX14B]
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ALL-MODE 4WD Transfer Basic Control
SDIA3396E
August 2012
2012 Pathfinder
DLN-16
< SYSTEM DESCRIPTION >
[TRANSFER: ATX14B]
4WD SYSTEM
Hydraulic Control Circuits
TRANSFER CONTROL UNIT
• Transfer control unit controls transfer control device and it directs shifts from 4H-4LO and 2WD-4WD.
• Self-diagnosis can be done.
TRANSFER SHIFT HIGH AND LOW RELAYS
Transfer shift high and low relays apply power supply to transfer control device (actuator motor).
TRANSFER SHUT OFF RELAY
Transfer shut off relay applies power supply to transfer motor relay.
4WD SHIFT SWITCH AND INDICATOR LAMPS
4WD Shift Switch
Able to select from 2WD, AUTO, 4H or 4LO.
4WD Shift Indicator Lamp
• Displays driving conditions selected by 4WD shift switch with 2WD, AUTO and 4H indicators while engine is
running. (When 4WD warning lamp is turned on, all 4WD shift indicator lamps are turned off.)
• Turns ON for approximately 1 second when ignition switch is turned ON, for purpose of lamp check.
4LO Indicator Lamp
LDIA0055E
WDIA0163E
August 2012
2012 Pathfinder
4WD SYSTEM
DLN-17
< SYSTEM DESCRIPTION >
[TRANSFER: ATX14B]
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• Displays 4LO condition while engine is running. 4LO indicator lamp flashes if transfer gear does not shift
completely under 2WD, AUTO, 4H
⇔
4LO. (When 4WD warning lamp is turned on, 4LO indicator lamp is
turned off.)
• Turns ON for approximately 1 second when ignition switch is turned ON, for purpose of lamp check.
4WD WARNING LAMP
Turns on or flashes when there is a malfunction in 4WD system.
Also turns on when ignition switch is turned ON, for purpose of lamp check. Turns OFF approximately 1 sec-
ond after the engine starts if system is normal.
4WD Warning Lamp Indication
ATP WARNING LAMP
When the A/T selector lever is in P position, the vehicle may move if the transfer case is in neutral. ATP warn-
ing lamp is turned on to indicate this condition to the driver.
LINE PRESSURE SWITCH
• With the transfer system design, control of the oil pressure provides the transmission of drive torque to the
front wheels. The main pressure to control the oil pressure is referred to as the line pressure.
• The line pressure switch determines whether or not adequate line pressure has built up under different oper-
ating conditions.
• The line pressure switch closes when line pressure is produced.
• The line pressure switch senses line pressure abnormalities and turns the 4WD warning lamp ON.
CLUTCH PRESSURE SWITCH
• The clutch pressure switch determines whether or not adequate clutch pressure has built up under different
operating conditions.
• The clutch pressure switch closes when clutch pressure is produced.
• The clutch pressure switch senses clutch pressure abnormalities and turns the 4WD warning lamp ON.
WAIT DETECTION SWITCH
• The wait detection switch operates when there is circulating torque produced in the propeller shaft (L
→
H) or
when there is a phase difference between 2-4 sleeve and clutch drum (H
→
L). After the release of the circu-
lating torque, the wait detection switch helps provide the 4WD lock gear (clutch drum) shifts. A difference
may occur between the operation of the 4WD shift switch and actual drive mode. At this point, the wait
detection switch senses an actual drive mode.
• The wait detection switch operates as follows.
- 4WD lock gear (clutch drum) locked: ON
- 4WD lock gear (clutch drum) released: OFF
• The wait detection switch senses an actual drive mode and the 4WD shift indicator lamp indicates the vehi-
cle drive mode.
ATP SWITCH
ATP switch detects if transfer case is in neutral by the position of the L-H shift fork.
NOTE:
Transfer case may be in neutral when shifting between 4H-4LO.
NEUTRAL-4LO SWITCH
The neutral-4LO switch detects that transfer gear is in neutral or 4LO (or shifting from neutral to 4LO) condi-
tion by L-H shift fork position.
Condition
4WD warning lamp
System normal
OFF
Lamp check
Turns ON when ignition switch is turned ON.
Turns OFF after engine start.
4WD system malfunction
ON
During self-diagnosis
Flashes malfunction mode.
Large difference in diameter of front/
rear tires
Flashes slow (1 flash / 2 seconds)
(Continues to flash until the ignition switch is turned OFF)
High fluid temperature in transfer case
Flashes rapidly (2 flashes / 1 second)
(Continues to flash until fluid temperature returns to normal)
August 2012
2012 Pathfinder
DLN-18
< SYSTEM DESCRIPTION >
[TRANSFER: ATX14B]
4WD SYSTEM
TRANSFER FLUID TEMPERATURE SENSOR
The transfer fluid temperature sensor detects the transfer fluid temperature and sends a signal to the transfer
control unit.
TRANSFER MOTOR
• The transfer motor drives the sub-oil pump to provide proper lubrication and oil pressure control when the
vehicle is at standstill, during low-speed operations or is being driven in reverse.
• The main oil pump is operated by the driving force of the mainshaft. In other words, sufficient oil pressure
buildup does not occur when the vehicle is at standstill or during low-speed operations. While the vehicle is
being driven in reverse, the main oil pump rotates in the reverse direction. Therefore the main oil pump does
not discharge oil pressure. During any of the above vehicle operations, the transfer motor drives the sub-oil
pump to compensate for insufficient oil pressure.
• The transfer motor operates as follows:
- The motor relay turns OFF in the 2WD mode.
- The motor relay operates as described in the table below in modes other than the 2WD mode.
• 4WD shift switch, transmission range switch, Neutral-4LO switch, vehicle speed sensor and throttle position
sensor are used in conjunction with the transfer motor.
Transfer Motor Relay Operation
*: After 2.5 seconds have elapsed.
CLUTCH PRESSURE SOLENOID VALVE
The clutch pressure solenoid valve distributes front and rear torque in AUTO mode.
2-4WD SHIFT SOLENOID VALVE
The 2-4WD shift solenoid valve operates to apply oil pressure to the wet-multiplate clutch, depending on the
drive mode. The driving force is transmitted to the front wheels through the clutch so the vehicle is set in the
4WD mode. Setting the vehicle in the 2WD mode requires no pressure buildup. In other words, pressure force
applied to the wet-multiplate clutch becomes zero.
TRANSFER CONTROL DEVICE
Integrates actuator motor and actuator position switch.
4WD shift switch
A/T selector lever position
Vehicle speed
(VSS)
Accelerator pedal position
Motor relay drive
command
2WD
—
—
—
OFF
4H (LOCK) and 4LO
N position
0
—
ON
P position
0
0 - 0.07/8
OFF*
0.07/8 - 1/8
HOLD
1/8 - MAX
ON
Other than R position
0 < VSS
≤
50 km/h (31 MPH)
—
ON
50 km/h (31 MPH) < VSS < 55
km/h (34 MPH)
HOLD
55 km/h (34 MPH)
≤
VSS
OFF
R position
—
—
ON
R position
—
—
ON
AUTO
P or N position
0
0 - 0.07/8
OFF*
0.07/8 - 1/8
HOLD
1/8 - MAX
ON
0 < VSS
≤
50 km/h (31 MPH)
—
ON
50 km/h (31 MPH) < VSS < 55
km/h (34 MPH)
HOLD
55 km/h (34 MPH)
≤
VSS
OFF
Other than R, P and N posi-
tion
0 < VSS
≤
50 km/h (31 MPH)
—
ON
50 km/h (31 MPH) < VSS < 55
km/h (34 MPH)
HOLD
55 km/h (34 MPH)
≤
VSS
OFF
August 2012
2012 Pathfinder
4WD SYSTEM
DLN-19
< SYSTEM DESCRIPTION >
[TRANSFER: ATX14B]
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Actuator Motor
Moves shift rods when signaled by transfer control unit.
Actuator Position Switch
Detects actuator motor position and then sends signal to transfer control unit.
Component Parts Location
INFOID:0000000007357350
WDIA0124E
August 2012
2012 Pathfinder
DLN-20
< SYSTEM DESCRIPTION >
[TRANSFER: ATX14B]
4WD SYSTEM
CAN Communication
INFOID:0000000007357351
LAN-52, "CAN System Specification Chart"
Cross-Sectional View
INFOID:0000000007357352
Power Transfer
INFOID:0000000007357353
POWER TRANSFER DIAGRAM
1.
Center case
2.
Front case
3.
Internal gear
4.
Planetary carrier assembly
5.
Sun gear assembly
6.
Main shaft
7.
L-H sleeve
8.
L-H fork
9.
Shift rod
10. 2-4 sleeve
11. 2-4 fork
12. Drive chain
13. Front drive shaft
14. Control valve assembly
15. Transfer motor
16. Rear case
17. Clutch piston
18. Press flange
19. Multiple disc clutch
20. Clutch hub assembly
21. Clutch drum assembly
WDIA0202E
August 2012
2012 Pathfinder
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