2008 INFINITI QX56 sensor

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: March 2010 2008 QX56

4WD SYSTEMDLN-17
< FUNCTION DIAGNOSIS > [ATX14B]
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CAN CommunicationINFOID:0000000001737099
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. Transfer dropping resistor E135
Transfer motor relay E153, E154
(View with battery removed)
Revision: March 2010 2008 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: March 2010
2008 QX56

DIAGNOSIS SYSTEM (TRANSFER CONTROL UNIT)DLN-21
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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 speed sensor signal 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: March 2010 2008 QX56

DLN-26
< COMPONENT DIAGNOSIS >[ATX14B]
P1807 VEHICLE SPEED SENSOR (A/T)
P1807 VEHICLE SPEED SENSOR (A/T)
DescriptionINFOID:0000000001737108
The transmission control module (TCM) transmits the output speed sensor signal via CAN communication to
Transfer control unit. DTC P1807 will set when a malfunction is detected in the output speed sensor signal or
an improper signal is input while driving.
DTC LogicINFOID:0000000001737109
DTC DETECTION LOGIC
DTC CONFIRMATION PROCEDURE
1.DTC CONFIRMATION PROCEDURE
1. Turn ignition switch ON.
2. Perform self-diagnosis.
Is DTC P1807 detected?
YES >> Perform diagnosis procedure. Refer to DLN-26, "Diagnosis Procedure".
NO >> Inspection End.
Diagnosis ProcedureINFOID:0000000001737110
1.CHECK DTC WITH TCM
Perform self-diagnosis with TCM. Refer to TM-32, "
CONSULT-III Function (TRANSMISSION)".
Is any malfunction detec ted by self-diagnosis?
YES >> Check the malfunctioning system.
NO >> GO TO 2.
2.CHECK TRANSFER CONTROL UNIT
Check transfer control unit input/output signal. Refer to DLN-80, "
Reference Value".
Are the inspection results normal?
YES >> GO TO 3.
NO >> Check transfer control unit pin terminals fo r damage or loose connection with harness connector.
If any items are damaged, repair or replace damaged parts.
3.CHECK DTC
Drive the vehicle and then perform self-diagnosis.
Are the inspection results normal?
YES >> Inspection End.
NO >> Perform self-diagnosis with TCM again.
DTC CONSULT-III Diagnostic item is detected when... Reference
[P1807] VHCL SPEED SEN·AT • Malfunction is detected in output
speed sensor signal that is output
from TCM through CAN communica-
tion.
• Improper signal is input while driving. Refer to
DLN-26
.
Revision: March 2010 2008 QX56

P1808 VEHICLE SPEED SENSOR (ABS)DLN-27
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P1808 VEHICLE SPEED SENSOR (ABS)
DescriptionINFOID:0000000001737111
The ABS actuator and electric unit (control unit) transmits a vehicle speed signal via CAN communication to
the transfer control unit. DTC P1808 sets when a malfunction is detected in the vehicle speed signal that is
output from the ABS actuator and electric unit (control unit) or an improper signal is input while driving.
DTC LogicINFOID:0000000001737112
DTC DETECTION LOGIC
DTC CONFIRMATION PROCEDURE
1.DTC CONFIRMATION PROCEDURE
1. Turn ignition switch ON.
2. Perform self-diagnosis.
Is DTC P1808 displayed?
YES >> Perform diagnosis procedure. Refer to DLN-27, "Diagnosis Procedure".
NO >> Inspection End.
Diagnosis ProcedureINFOID:0000000001737113
1.CHECK DTC WITH ABS ACTUATOR AND ELECTRIC UNIT (CONTROL UNIT)
Perform self-diagnosis with ABS actuator and electric unit (control unit). Refer to BRC-24, "
CONSULT-III
Function (ABS)".
Is any malfunction detected by self-diagnosis?
YES >> Check the malfunctioning system.
NO >> GO TO 2.
2.CHECK TRANSFER CONTROL UNIT
Check transfer control unit input/output signal. Refer to DLN-80, "
Reference Value".
Are the inspection results normal?
YES >> GO TO 3.
NO >> Check transfer control unit pin terminals for damage or loose connection with harness connector. If any items are damaged, repair or replace damaged parts.
3.CHECK DTC
Perform the self-diagnosis, after driving a vehicle for a while.
Are the inspection results normal?
YES >> Inspection End.
NO >> Perform self-diagnosis with ABS actuator and electric unit (control unit) again.
DTC CONSULT-III Diagnostic item is detected when... Reference
[P1808] VHCL SPEED SEN·ABS • Malfunction is detected in vehicle
speed signal that is output from ABS
actuator and electric unit (control unit)
through CAN communication.
• Improper signal is input while driving. Refer to DLN-27
.
Revision: March 2010
2008 QX56

P1826 TRANSFER FLUID TEMPERATUREDLN-67
< COMPONENT DIAGNOSIS > [ATX14B]
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P1826 TRANSFER FLUID TEMPERATURE
DescriptionINFOID:0000000001737155
Signal voltage from the transfer fluid temperature sens or is abnormally high (Transfer fluid temperature is
abnormally low) while driving.
DTC LogicINFOID:0000000001737156
DTC DETECTION LOGIC
DTC CONFIRMATION PROCEDURE
1.DTC CONFIRMATION PROCEDURE
1. Turn ignition switch ON.
2. Perform self-diagnosis.
Is DTC P1826 displayed?
YES >> Perform diagnosis procedure. Refer to DLN-67, "Diagnosis Procedure".
NO >> Inspection End.
Diagnosis ProcedureINFOID:0000000001737157
1.CHECK TRANSFER FLUID TE MPERATURE SENSOR SIGNAL
With CONSULT-III
1. Start engine.
2. Select DATA MONITOR mode for ALL MODE AWD/4WD with CONSULT-III.
3. Read out the value of FLUID TEMP SE.
Without CONSULT-III
1. Start engine.
2. Check voltage between transfer control unit harness connector
terminals and ground.
Are inspection results normal?
YES >> GO TO 4.
NO >> GO TO 2.
2.CHECK HARNESS BETWEEN TRANSF ER CONTROL UNIT AND TRANSFER TERMINAL CORD AS-
DTCCONSULT-III Diagnostic item is detected when... Reference
[P1826] OIL TEMP SEN Signal voltage from transfer fluid temper-
ature sensor is abnormally high (Trans-
fer fluid temperature is abnormally low)
while driving.Refer to DLN-67
.
Condition
Display value
(Approx.)
Transfer fluid temperature approx. 20 - 80 °C (68 - 176° F) 1.1 - 0.3V
Connector Terminal ConditionData
(Approx.)
E143 28 -
Ground Always
0V
31 -
Ground Ignition switch:
ON Transfer fluid temperature
approx. 20
°C (68 °F) 1.1V
Transfer fluid temperature
approx. 80 °C (176 °F) 0.3V
SDIA2742E
Revision: March 2010
2008 QX56

DLN-68
< COMPONENT DIAGNOSIS >[ATX14B]
P1826 TRANSFER FLUID TEMPERATURE
SEMBLY
1. Turn ignition switch OFF. (Stay for at least 5 seconds.)
2. Disconnect transfer control unit harness connector and
transfer terminal cord assembly harness connec-
tor.
3. Check continuity between the following terminals.
- Transfer control unit harness connector E143 terminal 28 and
transfer terminal cord assembly harness connector F56 terminal
3 .
- Transfer control unit harness connector E143 terminal 31 and transfer terminal cord assembly harness connector F56 terminal
2.
Also check harness for short to ground and short to power.
Are inspection results normal?
YES >> GO TO 3.
NO >> Repair or replace damaged parts.
3.CHECK TRANSFER FLUI D TEMPERATURE SENSOR
1. Turn ignition switch OFF. (Stay for at least 5 seconds.)
2. Disconnect transfer terminal cord assembly harness connector.
3. Check resistance between transfer terminal cord assembly ter- minals 2 and 3.
Are inspection results normal?
YES >> GO TO 4.
NO >> Replace transfer fluid temperature sensor. Refer to DLN-16, "
Component Parts Location".
4.CHECK TRANSFER CONTROL UNIT
Check transfer control unit input/output signal. Refer to DLN-80, "
Reference Value".
Are inspection results normal?
YES >> GO TO 5.
NO >> Check transfer control unit pin terminals fo r damage or loose connection with harness connector.
If any items are damaged, repair or replace damaged parts.
5.CHECK DTC
Drive the vehicle and then perform self-diagnosis.
Are inspection results normal?
YES >> Inspection End.
NO >> Replace transfer control unit. Refer to DLN-128, "
Removal and Installation".
Component InspectionINFOID:0000000001737158
1. Turn ignition switch OFF. (Stay for at least 5 seconds.)
2. Disconnect transfer terminal cord assembly harness connector.Continuity should exist.
SDIA2743E
Temperature
°C ( °F) Resistance (Approx.)
20 (68) 2.5 kΩ
80 (176) 0.3 kΩ
WDIA0188E
Revision: March 2010 2008 QX56