2009 INFINITI QX56 transmission

4WD SYSTEMDLN-15
< FUNCTION DIAGNOSIS > [ATX14B]
C
EF
G H
I
J
K L
M A
B
DLN
N
O P
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-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
output.
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: December 20092009 QX56

DLN-26
< COMPONENT DIAGNOSIS >[ATX14B]
P1807 VEHICLE SPEED
SENSOR (A/T)
P1807 VEHICLE SPEED SENSOR (A/T)
DescriptionINFOID:0000000003772087
The transmission control module (TCM ) transmits the output shaft revolution signal via CAN communication to
Transfer control unit. DTC P1807 will set when a malfunc tion is detected in the output shaft revolution signal
or an improper signal is input while driving.
DTC LogicINFOID:0000000003772088
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:0000000003772089
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-81, "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 shaft
revolution signal that is output from
TCM through CAN communication.
 Improper signal is input while driving. Refer to
DLN-26
.
Revision: December 20092009 QX56

DLN-38
< COMPONENT DIAGNOSIS >[ATX14B]
P1816 TRANSMISSION RANGE SWITCH
P1816 TRANSMISSION RANGE SWITCH
DescriptionINFOID:0000000003772105
The transmission range switch transmits the A/T positi
on indicator signal (transmission range switch signal)
via CAN communication to the transfer control unit. DTC P1816 will set when the transmission range switch
signal is malfunctioning or there is a communication error.
DTC LogicINFOID:0000000003772106
DTC DETECTION LOGIC
DTC CONFIRMATION PROCEDURE
1.DTC CONFIRMATION PROCEDURE
1. Turn ignition switch ON.
2. Perform self-diagnosis.
Is DTC P1816 displayed?
YES >> Perform diagnosis procedure. Refer to DLN-38, "Diagnosis Procedure".
NO >> Inspection End.
Diagnosis ProcedureINFOID:0000000003772107
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-81, "Reference Value"
.
Are 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 inspection results normal?
YES >> Inspection End.
NO >> Perform self-diagnosis with TCM again.
DTC CONSULT-III Diagnostic item is detected when... Reference
[P1816] PNP SW/CIRC When transmission range switch signal
is malfunction or communication error
between the control units.Refer to
DLN-38
.
Revision: December 20092009 QX56

DLN-80
< COMPONENT DIAGNOSIS >[ATX14B]
U1010 CONTROL UNIT (CAN)
U1010 CONTROL UNIT (CAN)
DescriptionINFOID:0000000005912150
CAN (Controller Area Network) is a serial communication
line for real time application. It is an on-vehicle mul-
tiplex communication line with high data communication s peed and excellent error detection ability. Many elec-
tronic control units are equipped onto a vehicle, and each control unit shares information and links with other
control units during operation (not independent). In CA N 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 communicate data but selectively reads required data only.
DTC LogicINFOID:0000000005912151
DTC DETECTION LOGIC
DTC CONFIRMATION PROCEDURE
1.DTC REPRODUCTION PROCEDURE
With CONSULT-III
1. Turn the ignition switch ON.
2. Perform transfer control unit self-diagnosis. Refer to DLN-18, "CONSULT-III Function (ALL MODE AWD/
4WD)".
Is DTC U1010 detected?
YES >> Proceed to diagnosis procedure. Refer to DLN-80, "Diagnosis Procedure".
NO >> Inspection End.
Diagnosis ProcedureINFOID:0000000005912152
1.CHECK TRANSFER CONTROL UNIT CONNECTOR
Check transfer control unit connectors for disconnection and deformation.
Is the inspection result normal?
YES >> Replace transfer control unit. Refer to DLN-130, "Removal and Installation".
NO >> Repair or replace parts as necessary.
DTC Display item Malfunction detected condition Possible cause
U1010 CONTROL UNIT (CAN) Detecting error during the initial diagno-
sis of CAN controller of transfer control
unit.Malfunction of transfer control unit
Revision: December 20092009 QX56

DLN-82
< ECU DIAGNOSIS >[ATX14B]
TRANSFER CONTROL UNIT
ATP SWITCH [ON/OFF] Condition of ATP switch Vehicle stopped
 Engine running
 A/T selector lever N posi-
tion
 Brake pedal depressed 4WD shift switch
: 4H to 4LO or 4LO to 4H
(While actuator motor is
operating.)
ON
Except the above OFF
WAIT DETCT SW [ON/
OFF] Condition of wait detec-
tion switch  Vehicle stopped
 Engine running
 A/T selector lever N posi-
tion
 Brake pedal depressed 4WD shift switch: 2WD,
AUTO or 4H
OFF
4WD shift switch: 4H to
4LO (While actuator mo-
tor is operating.) OFF
→ON
4WD shift switch: 4LO to
4H (While actuator motor
is operating.) ON
→OFF
4WD shift switch: 4LO ON
LINE PRES SW [ON/
OFF] Condition of line pres-
sure switch  A/T selector lever D position
 4WD shift switch: AUTO
ON
 Except the above
 The vehicle has been left at room temperature for 5
minutes and more with ig-
nition switch in OFF posi-
tion.  Ignition switch: ON
 A/T selector lever: P or
N position
 4WD shift switch: other than AUTO OFF
CL PRES SW [ON / OFF] Condition of clutch pres-
sure switch  Vehicle stopped
 Engine running
 A/T selector lever D position
 4WD shift switch: AUTO or 4H (Wait function is not op-
erating.) ON
 Vehicle stopped
 Engine running
 4WD shift switch: 2WD (Wait function is not operating.) OFF
N POSI SW AT [ON/
OFF] Input condition from
transmission range
switch  Vehicle stopped
 Engine running
 Brake pedal depressed A/T selector lever posi-
tion: N
ON
Except the above OFF
R POSI SW AT [ON/
OFF] Input condition from
transmission range
switch  Vehicle stopped
 Engine running
 Brake pedal depressed A/T selector lever posi-
tion: R
ON
Except the above OFF
P POSI SW AT [ON/OFF] Input condition from
transmission range
switch  Vehicle stopped
 Engine running
 Brake pedal depressed A/T selector lever posi-
tion: P
ON
Except the above OFF
ABS OPER SW [ON/
OFF] Condition of ABS operat-
ing ABS is operating. ON
ABS is not operating. OFF
VDC OPER SW [ON/
OFF] Condition of VDC operat-
ing VDC is operating. ON
VDC is not operating. OFF
TCS OPER SW [ON/
OFF] Condition of TCS operat-
ing TCS is operating. ON
TCS is not operating. OFF
THROTTLE POSI [0.0/8] Condition of throttle
opening When depressing accelerator pedal
(Value rises gradually in response to throttle position.)
0.0/8 - 8.0/8
4WD MODE [AUTO/
LOCK/2WD/4L] Control status of 4WD
(Output condition of 4WD
shift indicator lamp and
4LO indicator lamp)  Vehicle stopped
 Engine running
 A/T selector lever N posi-
tion
 Brake pedal depressed 4WD shift switch: 2WD 2WD
4WD shift switch: AUTO AUTO
4WD shift switch: 4H LOCK
4WD shift switch: 4LO 4L
Monitored item [Unit] Content Condition Display value
Revision: December 20092009 QX56

DLN-98
< ECU DIAGNOSIS >[ATX14B]
TRANSFER CONTROL UNIT
DTC CONSULT-III Diagnostic item is detected when... Reference
[P1802] CONTROL UNIT 1 Malfunction is detected in the memory (RAM) sys-
tem of transfer control unit.
Refer to DLN-24
.
[P1803] CONTROL UNIT 2 Malfunction is detected in the memory (ROM) sys-
tem of transfer control unit.
[P1804] CONTROL UNIT 3 Malfunction is detected
in the memory (EEPROM)
system of transfer control unit.
[P1807] VHCL SPEED SEN·AT  Malfunction is detected in output shaft revolution
signal that is output from TCM through CAN com-
munication.
 Improper signal is input while driving. Refer to
DLN-26
.
[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
.
[P1809] CONTROL UNIT 4 AD converter system of transfer control unit is mal-
functioning. Refer to
DLN-24
.
[P1810] 4L POSI SW TF Improper signal from neutral-4LO switch is input due
to open or short circuit. Refer to
DLN-28
.
[ P 1 8 11 ] B AT T E R Y V O LTA G E Power supply voltage for transfer control unit is ab-
normally low while driving.
Refer to
DLN-22
.
[P1813] 4WD MODE SW More than two switch inputs are simultaneously de-
tected due to short circuit of 4WD shift switch. Refer to
DLN-31
.
[P1814] 4WD DETECT SWITCH Improper signal from wait detection switch is input
due to open or short circuit. Refer to
DLN-35
.
[P1816] PNP SW/CIRC When transmission range switch signal is malfunc-
tion or communication error between the control
units. Refer to
DLN-38
.
[P1817] SHIFT ACTUATOR  Motor does not operate properly due to open or
short circuit in actuator motor.
 Malfunction is detected in the actuator motor. (When 4WD shift switch is operated and actuator
motor is not operated)
 Malfunction is detected in transfer shift high relay and transfer shift low relay. Refer to
DLN-39
.
[P1818] SHIFT ACT POSI SW  Improper signal from actuator position switch is in-
put due to open or short circuit.
 Malfunction is detected in the actuator position
switch. Refer to
DLN-45
.
[P1819] SHIFT ACT CIR  Transfer control device actuator circuit is shorted
or open. (Malfunctions are detected when transfer
shift relay circuit is open/shorted or relay monitor
circuit is open/shorted.)
 Malfunction occurs in transfer control device drive circuit.
 Malfunction is detected in transfer shut off relay. Refer to
DLN-48
.
[P1820] ENGINE SPEED SIG  Malfunction is detected in engine speed signal
that is output from ECM through CAN communi-
cation.
 Improper signal is input while driving. Refer to
DLN-52
.
[P1822] DUTY SOLENOID Proper voltage is not applied to clutch pressure so-
lenoid valve due to open or short circuit. Refer to
DLN-53
.
[P1823] 2-4WD SOLENOID Proper voltage is not applied to 2-4WD solenoid
valve due to open or short circuit. Refer to
DLN-57
.
[P1824] MOTOR RELAY Motor does not operate properly due to open or
short circuit in transfer motor or transfer motor relay.
Refer to
DLN-61
.
Revision: December 20092009 QX56

TRANSFER CONTROL UNITDLN-99
< ECU DIAGNOSIS > [ATX14B]
C
EF
G H
I
J
K L
M A
B
DLN
N
O P
CAUTION:
 If CAN COMM CIRCUIT [U1000] or CONTROL UNIT (CAN) [U1010] is displayed with other DTCs, first perform the trouble
diagnosis for CAN communication line.
 If ABS OP SIG [P1830], VDC OP SIG [P1831] or TCS OP SIG [P1832] is displayed, first perform the trouble diagnosis for ABS system.
 If VHCL SPEED SEN·AT [P1807] is displayed, firs t perform the trouble diagnosis for A/T system.
NOTE:
 If SHIFT ACT POSI SW [P1818] or SHIFT ACT CIR [P1819] is disp layed, first erase self-diagnostic results. (SHIFT ACT POSI SW
[P1818] or SHIFT ACT CIR [P1819] may be displayed after installing transfer control unit or transfer assembly.)
 If CL PRES SW [P1827] or LINE PRES SW [P1828] is displayed only while driving in reverse, check the continuity of R position o n
transmission range switch. When there is no malfunction found in the electrical system, check the hydraulic system.
FLASH CODE CHART
[P1826] OIL TEMP SEN Signal voltage from transfer fluid temperature sen-
sor is abnormally high (Transfer fluid temperature is
abnormally low) while driving. Refer to
DLN-67.
[P1827] CLUTCH PRES SW  Improper signal from clutch pressure switch is in-
put due to open or short circuit.
 Malfunction occurs in clutch pressure switch or
hydraulic circuit. Refer to
DLN-70
.
[P1828] LINE PRES SW  Improper signal from line pressure switch is input
due to open or short circuit.
 Malfunction occurs in line pressure switch or hy-
draulic circuit. Refer to
DLN-73
.
[P1829] THROTTLE POSI SEN  Malfunction is detected in accelerator pedal posi-
tion signal that is output from ECM through CAN
communication.
 Signal voltage from accelerator pedal position sensor is abnormally high or low. Refer to
DLN-76
.
[P1830] ABS OP SIG Malfunction is detected in ABS operation signal that
is output from ABS actuator and electric unit (control
unit) through CAN communication. Refer to
DLN-77
.
[P1831] VDC OP SIG Malfunction is detected in VDC operation signal that
is output from ABS actuator and electric unit (control
unit) through CAN communication.
Refer to
DLN-78
.
[P1832] TCS OP SIG Malfunction is detected in TCS operation signal that
is output from ABS actuator and electric unit (control
unit) through CAN communication. Refer to
DLN-79
.
[U1010] CONTROL UNIT (CAN) Detecting error during the initial diagnosis of CAN
controller of transfer control unit. Refer to
DLN-80
DTC CONSULT-III Diagnostic item is detected when... Reference
Flashing pattern Item Diagnostic item is detected when... Reference
2 Vehicle speed signal
(from A/T)  Malfunction is detected in output shaft revolution signal
that is output from TCM through CAN communication.
 Improper signal is input while driving. Refer to
DLN-26
.
3 Clutch pressure sole-
noid signal Proper voltage is not applied to clutch pressure solenoid
valve due to open or short circuit.
Refer to
DLN-53
.
4 2-4WD solenoid signal Proper voltage is not applied to 2-4WD solenoid valve due
to open or short circuit.
Refer to
DLN-57
.
5 Transfer motor Transfer motor does not operate properly due to open or
short circuit in transfer motor or transfer motor relay. Refer to
DLN-61
.
6 Vehicle speed signal
(from ABS)  Malfunction is detected in vehicle speed signal that is out-
put from ABS actuator and elec tric unit (control unit)
through CAN communication.
 Improper signal is input while driving. Refer to
DLN-27
.
7 CAN communication Malfunction has been detected from CAN communication
line. Refer to
LAN-51
.
Revision: December 20092009 QX56