2008 INFINITI QX56 transmission

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 A/T transmission range
switch status is displayed.
Signal input with CAN communication line.
R POSI SW AT [ON/OFF] ×–×R position signal of A/T transmission range
switch status is displayed.
Signal input with CAN communication line.
P POSI SW AT [ON/OFF] ×–×P position signal of A/T 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
tpu
t

.
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: 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

DLN-38
< COMPONENT DIAGNOSIS >[ATX14B]
P1816 PNP SWITCH
P1816 PNP SWITCH
DescriptionINFOID:0000000001737126
The A/T transmission range switch transmits the A/T pos
ition indicator signal (transmission range switch sig-
nal) via CAN communication to the transfer control uni t. DTC P1816 will set when the A/T transmission range
switch signal is malfunctioning or there is a communication error.
DTC LogicINFOID:0000000001737127
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:0000000001737128
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 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 A/T transmission range switch
signal is malfunction or communication
error between the control units.Refer to
DLN-38
.
Revision: March 2010 2008 QX56

TRANSFER CONTROL UNITDLN-81
< ECU DIAGNOSIS > [ATX14B]
C
EF
G H
I
J
K L
M A
B
DLN
N
O P
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 A/T
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 A/T
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 A/T
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 OPE R
SW [O

N/
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 ConditionDisplay value
Revision: March 2010 2008 QX56

DLN-96
< 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 speed sensor
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: March 2010
2008 QX56

TRANSFER CONTROL UNITDLN-97
< 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 [P 1832] 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
.
DTC CONSULT-III Diagnostic item is detected when... Reference
Flashing pattern
ItemDiagnostic item is detected when... Reference
2 Vehicle speed signal
(from A/T) • Malfunction is detected in output speed sensor 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 electric 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
.
8 AD converter AD converter system of transfer control unit is malfunction-
ing. Refer to DLN-24
.
Revision: March 2010
2008 QX56

DLN-98
< ECU DIAGNOSIS >[ATX14B]
TRANSFER CONTROL UNIT
9Transfer fluid tempera-
ture Signal voltage from transfer fluid temperature sensor is ab-
normally high (Transfer fluid temperature is abnormally low)
while driving.
Refer to DLN-67.
10 Neutral-4LO switch Improper signal from neutral-4LO switch is input due to
open or short circuit. Refer to DLN-28
.
11 Clutch pressure switch • Improper signal is input due to open or short circuit.
• Malfunction occurs in clutch pressure switch or hydraulic
circuit. Refer to DLN-70
.
12 Line pressure switch • Improper signal is input due to open or short circuit.
• Malfunction occurs in line pressure switch or hydraulic
circuit. Refer to DLN-73
.
13 Engine speed signal
(from ECM) • Malfunction is detected in engine speed signal that is out-
put from ECM through CAN communication.
• Improper signal is input while driving. Refer to DLN-52
.
14 Accelerator pedal posi-
tion sensor (from
ECM) • Malfunction is detected in accelerator pedal position sig-
nal that is output from ECM through CAN communication.
• Signal voltage from accelerator pedal position sensor is abnormally high or low. Refer to DLN-76
.
15 Power supply Power supply voltage for transfer control unit is abnormally
low while driving. Refer to DLN-22
.
16 4WD shift switch More than two switch inputs are simultaneously detected
due to short circuit of 4WD shift switch.
Refer to DLN-31
.
17 ABS operation signal
(from ABS) Malfunction is detected in ABS operation signal that is out-
put from ABS actuator and electric unit (control unit)
through CAN communication.
Refer to DLN-77
.
18 Wait detection switch Improper signal from wait detection switch is input due to
open or short circuit.
Refer to DLN-35
.
19 Actuator motor • Motor does not operate properly due to open or short cir-
cuit 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
.
20 Actuator position
switch • Improper signal from actuator position switch is input due
to open or short circuit.
• Malfunction is detected in the actuator position switch. Refer to DLN-45
.
21 Actuator circuit • Transfer control device actuator circuit is shorted or open.
(Malfunctions are detected when motor relay circuit is
open/shorted or relay transfer shift circuit is open/short-
ed.)
• Malfunction occurs in transfer control device drive circuit. Refer to DLN-48
.
22 VDC operation signal
(from VDC) Malfunction is detected in VDC operation signal that is out-
put from ABS actuator and electric unit (control unit)
through CAN communication.
Refer to DLN-78
.
23 TCS operation signal
(from TCS) Malfunction is detected in TCS operation signal that is out-
put from ABS actuator and electric unit (control unit)
through CAN communication.
Refer to DLN-79
.
24 Transmission range
switch signal (from
TCM) When transmission range switch signal is malfunction or
communication error between the control units.
Refer to DLN-38
.
Repeats flickering
every 2 to 5 sec. — System normal. Refer to DLN-100
Flashing pattern
ItemDiagnostic item is detected when... Reference
Revision: March 2010 2008 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 communication is displayed wi th other DTCs, first perform the trouble diagnosis for CAN communication line.
• If ABS operation signal, VDC operation signal or TCS operation si gnal is displayed, first perform the trouble diagnosis for
ABS system.
• If Output speed sensor signal is displayed, first perform the trouble diagnosis for A/T system.
NOTE:
• If actuator position switch or actuator circuit is displayed, first erase self-diagnostic results. (Actuator position switch o r actuator circuit
may be displayed after installing transfer control unit or transfer assembly.)
• If clutch pressure switch or line pressure switch is displayed only while driving in reverse, check the continuity of R positi on on trans-
mission range switch. When there is no malfunction found in the electrical system, check the hydraulic system.
Repeats flickering
every 0.25 sec.
Data erase display • Power supply failure of memory back-up.
• Battery performance is poor. Refer to DLN-22
.
No flickering Transmission range
switch or 4WD shift
switch Transmission range switch or 4WD shift switch circuit is
shorted or open.
Refer to DLN-38
or
DLN-31
.
Flashing pattern
ItemDiagnostic item is detected when... Reference
Revision: March 2010 2008 QX56