2010 INFINITI QX56 clutch

DLN-10
< FUNCTION DIAGNOSIS >[ATX14B]
4WD SYSTEM
FUNCTION DIAGNOSIS
4WD SYSTEM
System DiagramINFOID:0000000005148770
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.
AT P w a r n i n g l a m p 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.
Revision: April 20092010 QX56

DLN-14
< FUNCTION DIAGNOSIS >[ATX14B]
4WD SYSTEM
• 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 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, 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 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 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)
Revision: April 20092010 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 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 00 - 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: April 20092010 QX56

4WD SYSTEMDLN-17
< FUNCTION DIAGNOSIS > [ATX14B]
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CAN CommunicationINFOID:0000000005148773
Refer to LAN-14, "Trouble Diagnosis Flow Chart".
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: April 20092010 QX56

DLN-20
< FUNCTION DIAGNOSIS >[ATX14B]
DIAGNOSIS SYSTEM (T
RANSFER CONTROL UNIT)
4L SW [On/Off] ×–×4WD shift switch status is displayed.
(4L means 4LO of 4WD shift switch.)
N POSI SW TF [On/Off] ×–×Neutral-4LO switch signal status is displayed.
ATP SWITCH [On/Off] ×–×ATP switch signal status is displayed.
WAIT DETCT SW [On/Off] ×–×Wait detection switch status is displayed.
LINE PRES SW [On/Off] ×–×Line pressure switch status is displayed.
CL PRES SW [On/Off] ×–×Clutch pressure switch status is displayed.
N POSI SW AT [On/Off] ×–×N position signal of transmission range switch
status is displayed.
Signal input with CAN communication line.
R POSI SW AT [On/Off] ×–×R position signal of transmission range switch
status is displayed.
Signal input with CAN communication line.
P POSI SW AT [On/Off] ×–×P position signal of transmission range switch
status is displayed.
Signal input with CAN communication line.
ABS OPER SW [On/Off] ×–×ABS operation signal status is displayed.
Signal input with CAN communication line.
VDC OPER SW [On/Off] ×–×VDC operation signal status is displayed.
Signal input with CAN communication line.
TCS OPER SW [On/Off] ×–×TCS operation signal status is displayed.
Signal input with CAN communication line.
THROTTLE POSI [0.0/8] –×× Thottle position status is displayed.
Signal input with CAN communication line.
4WD MODE [AUTO/LOCK/2WD/4L] – ××Control status of 4WD recognized by transfer
control unit. (AUTO, 4H, 2WD or 4LO)
VHCL/S COMP [km/h] or [mph] –×× Vehicle speed recognized by transfer control
unit.
COMP CL TORQ [kgm] –×× Calculated torque recognized by transfer con-
trol unit.
DUTY SOLENOID [%] –×× Control value of clutch pressure solenoid.
2-4WD SOL [On/Off] –×× Output condition to 2-4WD solenoid.
2-4WD SOL MON [On/Off] ––×Check signal for transfer control unit signal
output.
MOTOR RELAY [On/Off] –×× Transfer motor relay signal status is dis-
played.
MOTOR RELAY MON [On/Off] ––×Check signal for transfer control unit signal
ou
t

put.
4WD FAIL LAMP [On/Off] –×× Control status of 4WD warning lamp is dis-
played.
2WD IND [On/Off] ––×Control status of 4WD shift indicator lamp
(2WD indicator lamp) is displayed.
AUTO IND [On/Off] ––×Control status of 4WD shift indicator lamp
(2WD and AUTO indicator lamp) is displayed.
LOCK IND [On/Off] ––×Control status of 4WD shift indicator lamp
(2WD, AUTO and Lock indicator) is displayed.
4L IND [On/Off] ––×Control status of 4LO indicator lamp is dis-
played.
Monitored item (Unit)
Monitor item selection
Remarks
ECU INPUT
SIGNALS MAIN
SIGNALS SELEC-
TION FROM
MENU
Revision: April 20092010 QX56

DIAGNOSIS SYSTEM (TRANSFER CONTROL UNIT)DLN-21
< FUNCTION DIAGNOSIS > [ATX14B]
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WORK SUPPORT
When there is no malfunction with transfer and 4WD sys tem, the following symptoms in AUTO mode may be
claimed by a customer: vibration when accelerating on a low µ road (snow-covered or icy road) or a slight
shock is felt at a few hertz as if it were being pushed lightly from behind.
It is possible to deal with these symptoms by changing the CLUTCH FORCE RELEASE LIMIT VALUE. How-
ever, be careful when changing the value because it may adversely affect driving performance.
Operation Procedure
1. Connect CONSULT-III.
2. Touch WORK SUPPORT.
3. Select from CLUTCH/F RLS LIM ADJ, screen of data monitor mode is displayed.
Clutch Force Release Limit Adjustment
1. Initial CLUTCH FORCE RELEASE LIMIT value 0.3 kgm appears under CONDITION SETTING on CON-
SULT-III display.
2. Touch 1.2 on the display.
3. Display changes to NOW ADJUSTING in a short time.
4. When clutch force release limit value is set to 1.2 kgm, current value 0.3 kgm shown on display will be replaced by 1.2 kgm and ADJUSTME NT COMPLETE will appear at the same time. Clutch force release
limit value setting is now complete.
ATP IND [On/Off] ––×Control status of ATP warning lamp is dis-
played.
SHIFT POS SW1 [On/Off] ×–×Actuator position switch 1 (Low) signal status
is displayed.
SHIFT POS SW2 [On/Off] ×–×Actuator position switch 2 (high) signal status
is displayed.
SHIFT ACT1 [On/Off] –×× Output condition to actuator motor (clockwise)
SHIFT AC MON1 [On/Off] ×–×Check signal for transfer control unit signal
output
SHIFT ACT2 [On/Off] –×× Output condition to actuator motor (counter-
clockwise)
SHIFT AC MON2 [On/Off] ×–×Check signal for transfer control unit signal
output
T/F F SPEED [km/h] or [mph] ×–×Displayed, but do not use.
A/T R SPEED [km/h] or [mph] ×–×Output shaft revolution signal (output speed
sensor) calculated by TCM.
Signal input with CAN communication line.
AT GEAR POSI [1/2/3/4/5] ×–×A/T actual gear position is displayed.
Monitored item (Unit)
Monitor item selection
Remarks
ECU INPUT
SIGNALS MAIN
SIGNALS SELEC-
TION FROM
MENU
1.2 kg-m : Tight corner braking symptom is alleviated. However, vibration may occur when acceler-
ating on a low µ road (icy road, etc.).
0.3 kg-m : Initial set value.
0.2 kg-m : Do not set to th is value because the tight
corner braking symptom will get worse.
Revision: April 20092010 QX56

DLN-54
< COMPONENT DIAGNOSIS >[ATX14B]
P1822 CLUTCH PRESSURE SOLENOID
P1822 CLUTCH PRESSURE SOLENOID
DescriptionINFOID:0000000005148817
Proper voltage is not applied to the clutch pres
sure solenoid valve due to open or short circuit.
DTC LogicINFOID:0000000005148818
DTC DETECTION LOGIC
DTC CONFIRMATION PROCEDURE
1.DTC CONFIRMATION PROCEDURE
1. Turn ignition switch ON.
2. Perform self-diagnosis.
Is DTC P1822 displayed?
YES >> Perform diagnosis procedure. Refer to DLN-54, "Diagnosis Procedure".
NO >> Inspection End.
Diagnosis ProcedureINFOID:0000000005148819
Regarding Wiring Diagram information, refer to DLN-89, "Wiring Diagram - ALL-MODE 4WD SYSTEM -".
1.CHECK CLUTCH PRESSURE SIGNAL
With CONSULT-III1. Start engine.
2. Select DATA MONITOR mode for ALL MODE AWD/4WD with CONSULT-III.
3. Read out the value of DUTY SOLENOID.
Without CONSULT-III1. Start engine.
2. Check voltage between transfer control unit harness connector
terminal and ground.
DTC CONSULT-III Diagnostic item is detected when... Reference
[P1822] DUTY SOLENOID Proper voltage is not applied to clutch
pressure solenoid valve due to open or
short circuit.Refer to
DLN-54
.
Condition Display value
• Vehicle stopped
• Engine running
• A/T selector lever N position
• Brake pedal depressed 4WD shift switch: 2WD
4%
4WD shift switch: AUTO 96 - 4%
4WD shift switch: 4H or
4LO 4%
SDIA2719E
Revision: April 20092010 QX56

P1822 CLUTCH PRESSURE SOLENOIDDLN-55
< COMPONENT DIAGNOSIS > [ATX14B]
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Are the inspection results normal?
YES >> GO TO 7.
NO >> GO TO 2.
2.CHECK HARNESS BETWEEN TRANSFER CONT ROL UNIT AND CLUTCH PRESSURE SOLENOID
VA LV E
1. Turn ignition switch OFF. (Stay for at least 5 seconds.)
2. Disconnect transfer control unit harness connector, tr ansfer terminal cord assembly harness connector
and transfer dropping resistor.
3. Check continuity between transfer control unit harness connec- tor E142 terminal 19 and transfer terminal cord assembly har-
ness connector F56 terminal 6.
4. Check continuity between transfer dropping resistor harness connector E135 terminal 2 and transfer terminal cord assembly
harness connector F56 terminal 6.
Also check harness for short to ground and short to power.
Are the inspection results normal?
YES >> GO TO 3.
NO >> Repair or replace damaged parts.
3.CHECK HARNESS BETWEEN TRAN SFER CONTROL UNIT AND TRANSFER DROPPING RESISTOR
1. Turn ignition switch OFF. (Stay for at least 5 seconds.)
2. Disconnect transfer control unit harness connecto r and transfer dropping resistor harness connector.
Connector TerminalConditionVoltage
(Approx.)
E142 10 -
Ground • Vehicle stopped
• Engine running
• A/T selector lever
N position
• Brake pedal de- pressed 4WD shift switch:
AUTO
4 - 14V
4WD shift switch:
2WD, 4H or 4LO Less than
1V
19 -
Ground • Vehicle stopped
• Engine running
• A/T selector lever
N position
• Brake pedal de-
pressed 4WD shift switch:
AUTO
1.5 - 3V
4WD shift switch:
2WD, 4H or 4LO Less than
1V
Continuity should exist.
SDIA2720E
Continuity should exist.
SDIA2721E
Revision: April 20092010 QX56