2009 INFINITI QX56 200

DLN-12
< FUNCTION DIAGNOSIS >[ATX14B]
4WD SYSTEM
ALL-MODE 4WD Transfer Basic Control
SDIA3396E
Revision: December 20092009 QX56

4WD SYSTEMDLN-13
< FUNCTION DIAGNOSIS > [ATX14B]
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Hydraulic Control Circuits
TRANSFER CONTROL UNIT
 Transfer control unit controls transfer control dev
ice 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
Revision: December 20092009 QX56

DLN-14
< FUNCTION DIAGNOSIS >[ATX14B]
4WD SYSTEM
 Displays 4LO condition while engine is running. 4LO indi
cator 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 che\
ck. 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, cont rol 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 pressu re 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 provi de the 4WD lock gear (clutch drum) shifts. A difference
may occur between the operation of the 4WD shift swit ch 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 tr ansfer 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)
Revision: December 20092009 QX56

4WD SYSTEMDLN-15
< FUNCTION DIAGNOSIS > [ATX14B]
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TRANSFER FLUID TEMPERATURE SENSOR
The transfer fluid temperature sensor detects the trans fer fluid temperature and sends a signal to the transfer
control unit.
TRANSFER MOTOR
 The transfer motor drives the sub-oil pump to provi de 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 t he mainshaft. In other words, sufficient oil pressure
buildup does not occur when the vehicle is at standsti ll 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 vehi cle 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 trans mitted 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
Revision: December 20092009 QX56

DLN-16
< FUNCTION DIAGNOSIS >[ATX14B]
4WD SYSTEM
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 LocationINFOID:0000000003772077
AWDIA0549ZZ
Revision: December 20092009 QX56

4WD SYSTEMDLN-17
< FUNCTION DIAGNOSIS > [ATX14B]
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CAN CommunicationINFOID:0000000003772078
Refer to LAN-51, "DTC Index".
1. A: Transfer shut off relay E69
B: Transfer shift low relay E47
C: Transfer shift high relay E46 2. A: Actuator
B: Transfer control device F58
C: Actuator lever
D: Transfer case 3. Wait detection switch F59
(View with transfer case removed)
4. A: Clutch pressure switch B: Line pressure switch
C: Transfer fluid temperature sensor
D: 2-4WD shift solenoid valve
E: Clutch pressure solenoid valve
(View with contro l valve removed
from transfer case) 5. A: Neutral 4LO switch F60
B: ATP switch F55
C: Transfer motor F57
D: Transfer terminal cord assembly F56
E: Oil filter 6. Combination meter M23, M24
A: 4WD warning lamp
B: ATP warning lamp
C: 4LO indicator lamp (located in in-
formation display)
D: 4WD shift indicator lamp
7. 4WD shift switch M141 8. Transfer control unit E142, E143 9. A: Transfer dropping resistor E135 B: Transfer motor relay E153, E154
(View with battery removed)
Revision: December 20092009 QX56

DLN-18
< FUNCTION DIAGNOSIS >[ATX14B]
DIAGNOSIS SYSTEM (T
RANSFER CONTROL UNIT)
DIAGNOSIS SYSTEM (TRA NSFER CONTROL UNIT)
CONSULT-III Function (ALL MODE AWD/4WD)INFOID:0000000003772079
FUNCTION
CONSULT-III can display each diagnostic item us ing the diagnostic test modes shown following.
SELF-DIAG RESULT MODE
Operation Procedure
1. Connect CONSULT-III.
2. With engine at idle, touch SELF-DIAG RESULTS.
Display shows malfunction experienced since the last erasing operation.
NOTE:
The details for TIME are as follows:
 0: Error currently detected with transfer control unit.
 Except for 0: Error detected in the pa st and memorized with transfer control unit.
Detects frequency of driving after DTC occurs (frequency of turning ignition switch ON/OFF).
How to Erase Self-d iagnostic Results
1. Perform applicable inspection of malfunctioning item and then repair or replace.
2. Start engine and select SELF-DIAG RESULTS m ode for ALL MODE AWD/4WD with CONSULT-III.
3. Touch ERASE on CONSULT-III screen to erase DTC memory. CAUTION:
If memory cannot be erased, pe rform applicable diagnosis.
SELF-DIAGNOSTIC PROCEDURE (WITHOUT CONSULT-III)
Description
If the engine starts when there is a malfunction in the 4W D system, the 4WD warning lamp turns ON or flickers
in the combination meter. When the system functions properly, the warning lamp turns ON when the ignition
switch is turned to ON, and it turns OFF after engine starts . To locate the cause of a malfunction, start the self-
diagnosis function. The 4WD warning lamp in the co mbination meter will indicate the malfunction area by
flashing according to the self-diagnostic results. Refer to DLN-97, "DTC Index"
.
Diagnostic Procedure
1. Warn up engine.
2. Move A/T selector lever to P position.
3. Turn 4WD shift switch to 2WD position.
4. Turn ignition switch ON and OFF at least twice, and then turn ignition switch OFF.
5. Turn 4WD shift switch to AUTO position.
6. Turn ignition switch ON. (Do not start engine.)
7. 4WD warning lamp ON.
8. Move A/T selector lever to R position.
9. Turn 4WD shift switch to 2WD, AUTO and 2WD in order.
10. Move A/T selector lever to D position.
11. Turn 4WD shift switch to 4H, AUTO and 4H in order.
ALL MODE AWD/4WD diagnostic mode Description
SELF-DIAG RESULTS Displays transfer control unit self-diagnosis results.DATA MONITOR Displays transfer control unit input/output data in real time.
WORK SUPPORT Supports inspections and adjustments. Commands are transmitted to the transfer control
unit for setting the status suitable for required operation, input/output signals are received
from the transfer control unit and received data is displayed.
CAN DIAG SUPPORT MNTR The results of transmit/receive diagnosis of CAN communication can be read. ECU PART NUMBER Transfer control unit part number can be read.
Revision: December 20092009 QX56

DIAGNOSIS SYSTEM (TRANSFER CONTROL UNIT)
DLN-19
< FUNCTION DIAGNOSIS > [ATX14B]
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12. Move A/T selector lever to N position.
13. Turn 4WD shift switch to AUTO position.
14. Move A/T selector lever to P position.
15. Read the flickering of 4WD warning lamp.
Self-diagnosis example
ERASE SELF-DIAGNOSIS
 In order to make it easier to find the cause of hard-to-duplicate malfunctions, malfunction information is
stored into the control unit as necessary during use by the user. This memory is not erased no matter how
many times the ignition switch is turned ON and OFF.
 However, this information is erased by turning igni tion switch OFF after performing self-diagnostics or by
erasing the memory using the CONSULT-III.
DATA MONITOR MODE
Operation Procedure
1. Connect CONSULT-III.
2. Touch DATA MONITOR.
3. Select from SELECT MONITOR ITEM, screen of data monitor mode is displayed.
NOTE:
When malfunction is detected, CONSUL T-III performs REAL-TIME DIAGNOSIS.
Also, any malfunction detected while in th is mode will be displayed at real time.
Display Item List
×: Standard –: Not applicable
PDIA0227E
Monitored item (Unit) Monitor item selection
Remarks
ECU INPUT
SIGNALS MAIN
SIGNALS SELEC-
TION FROM MENU
VHCL/S SEN·FR [km/h] or [mph] ×–×Wheel speed calculated by ABS actuator and
electric unit (control unit).
Signal input with CAN communication line.
VHCL/S SEN·RR [km/h] or [mph] ×–×Wheel speed calculated by TCM.
Signal input with CAN communication line.
ENGINE SPEED [rpm] ×–×Engine speed calculated by ECM.
Signal input with CAN communication line.
THRTL POS SEN [V] ×–×Accelerator peda
l position (APP) sensor sig-
nal voltage is displayed.
Signal input with CAN communication line.
FLUID TEMP SE [V] ×–×Transfer fluid temperature sensor signal volt-
age is displayed.
BATTERY VOLT [V] ×–×Power supply voltage for transfer control unit.
2WD SWITCH [ON/OFF] ×–×4WD shift switch status is displayed.
AUTO SWITCH [ON/OFF] ×–×4WD shift switch status is displayed.
LOCK SWITCH [ON/OFF] ×–×4WD shift switch status is displayed.
(LOCK means 4H of 4WD shift switch.)
Revision: December 20092009 QX56