2009 INFINITI QX56 engine

DLN-84
< ECU DIAGNOSIS >[ATX14B]
TRANSFER CONTROL UNIT
MOTOR RELAY MON
[ON/OFF]Check signal for transfer
control unit signal output  Accelerator pedal de-
pressed
 Vehicle stopped
 Engine running
 Brake pedal depressed 4WD shift switch: 2WD OFF
4WD shift switch: AUTO
or 4LO (A/T selector lever
P or N position)
OFF
(ON for approx. 2
sec. after shifting to P and N.)
4WD shift switch: AUTO
or 4LO (Except for A/T se-
lector lever P or N posi-
tion) ON
4WD shift switch: 4H (A/T
selector lever P position) OFF
(ON for approx. 2
sec. after shifting to P.)
4WD shift switch: 4H (Ex-
cept for A/T selector lever
P position) ON
4WD FAIL LAMP [ON/
OFF] Condition of 4WD warn-
ing lamp 4WD warning lamp: ON ON
4WD warning lamp: OFF OFF
2WD IND [ON/OFF] Condition of 4WD shift in-
dicator lamp (2WD indi-
cator lamp) 2WD indicator lamp of 4WD shift indicator lamp: OFF OFF
2WD indicator lamp of 4WD shift indicator lamp: ON ON
AUTO IND [ON/OFF] Condition of 4WD shift in-
dicator lamp
(AUTO indi-
cator lamp) AUTO indicator lamp of 4WD shift indicator lamp: OFF OFF
AUTO indicator lamp of 4WD shift indicator lamp: ON ON
LOCK IND [ON/OFF] Condition of 4WD shift in-
dicator lamp (Lock indi-
cator lamp) Lock indicator lamp of 4WD shift indicator lamp: OFF OFF
Lock indicator lamp of 4WD shift indicator lamp: ON ON
4L IND [ON/OFF] Condition of 4LO indica-
tor lamp condition 4LO indicator lamp: OFF OFF
4LO indicator lamp: ON ON
ATP IND [ON/OFF] Condition of ATP indica-
tor lamp ATP indicator lamp: ON ON
AT P i n d i c a t o r l a m p : O F F O F F
SHIFT POS SW1 [ON/
OFF] Condition of actuator po-
sition switch 1
(Low)  Vehicle stopped
 Engine running
 A/T selector lever N posi-
tion
 Brake pedal depressed 4WD shift switch: 4LO ON
4WD shift switch: 2WD,
AUTO or 4H
OFF
SHIFT POS SW2 [ON/
OFF] Condition of actuator po-
sition switch 2
(High)  Vehicle stopped
 Engine running
 A/T selector lever N posi-
tion
 Brake pedal depressed 4WD shift switch: 4H,
AUTO or 2WD
ON
4WD shift switch: 4LO OFF
SHIFT ACT1 [ON/OFF] Output condition to actu-
ator motor (High)  Vehicle stopped
 Engine running
 A/T selector lever N posi-
tion
 Brake pedal depressed
4WD shift switch: 4H to
4LO (Wait function is op-
erating.) ON
Except the above OFF
SHIFT AC MON1 [ON/
OFF] Check signal for transfer
control unit signal output  Vehicle stopped
 Engine running
 A/T selector lever N posi-
tion
 Brake pedal depressed 4WD shift switch: 4H to
4LO (Wait function is op-
erating.)
ON
Except the above OFF
SHIFT ACT2 [ON/OFF] Output condition to actu-
ator motor (Low)  Vehicle stopped
 Engine running
 A/T selector lever N posi-
tion
 Brake pedal depressed 4WD shift switch: 4LO to
4H (Wait function is oper-
ating.)
ON
Except the above OFF
Monitored item [Unit] Content Condition Display value
Revision: December 20092009 QX56

TRANSFER CONTROL UNITDLN-85
< ECU DIAGNOSIS > [ATX14B]
C
EF
G H
I
J
K L
M A
B
DLN
N
O P
PHYSICAL VALUES
Terminal Layout
SHIFT AC MON2 [ON/
OFF] Check signal for transfer
control unit signal output  Vehicle stopped
 Engine running
 A/T selector lever N posi-
tion
 Brake pedal depressed 4WD shift switch: 4LO to
4H (Wait function is oper-
ating.)
ON
Except the above OFF
T/F F SPEED [km/h] or
[mph] Displayed, but do not use.
A/T R SPEED [km/h] or
[mph] Condition of vehicle
speed sensor A/T (output
speed sensor)
During driving Approximately
matches the out-
put shaft speed.
AT GEAR POSI [1/2/3/4/
5] Condition of A/T selector
lever position
Displays actual A/T gear position. 1
2
3
4
5
Monitored item [Unit] Content Condition Display value
WDIA0378E
Te r m i n a l
Wire
color Item Condition Data (Approx.)
1 GR 2-4WD shift solenoid valve  Vehicle stopped
 Engine running
 A/T selector lever
“N” position
 Brake pedal de- pressed 4WD shift switch: 2WD 0V
4WD shift switch: AUTO, 4H or 4LO Battery voltage
2 B/W 4WD shift indicator lamp
(2WD indicator lamp) 2WD indicator lamp: OFF Battery voltage
2WD indicator lamp: ON 0V
3 B Ground Always 0V
4 Y/L Transfer shift high relay  Vehicle stopped
 Engine running
 A/T selector lever
“N” position
 Brake pedal de-
pressed 4WD shift switch: 4H to 4LO (“Wait” func-
tion is operating.)
Battery voltage
Except the above 0V
5 W/B 4WD warning lamp 4WD warning lamp: ON 0V
4WD warning lamp: OFF Battery voltage
6 B Ground Always 0V
7 L CAN-H — —
8 P CAN-L — —
9G/W 4WD shift switch
(2WD) Ignition switch: ON4WD shift switch: 2WD Battery voltage
4WD shift switch: AUTO, 4H or 4LO 0V
Revision: December 20092009 QX56

DLN-86
< ECU DIAGNOSIS >[ATX14B]
TRANSFER CONTROL UNIT
10 L/W Transfer dropping resistor 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
11 L 4WD shift indicator lamp
(Lock indicator lamp) Lock indicator lamp of 4WD shift indicator lamp: OFF Battery voltage
Lock indicator lamp of 4WD shift indicator lamp: ON 0V
12 W/G 4LO indicator lamp 4LO indicator lamp: OFF Battery voltage
4LO indicator lamp: ON 0V
13 G/B Transfer shift low relay  Vehicle stopped
 Engine running
 A/T selector lever
“N” position
 Brake pedal de-
pressed 4WD shift switch: 4LO to 4H (“Wait” func-
tion is operating.)
Battery voltage
Except the above 0V
14 LG Transfer motor relay  Accelerator pedal
depressed
 Vehicle stopped
 Engine running
 Brake pedal de- pressed 4WD shift switch: 2WD Battery voltage
4WD shift switch: AUTO or 4LO (A/T selec-
tor lever “P” or “N” position)
Battery voltage
(0V for approx.
2 sec. after
shifting to “P”
and “N”.)
4WD shift switch: AUTO or 4LO (Except for
A/T selector lever “P” or “N” position) 0V
4WD shift switch: 4H (A/T selector lever
“P” position) Battery voltage
(0V for approx.
2 sec. after
shifting to “P”.)
4WD shift switch: 4H (Except for A/T selec-
tor lever “P” position) 0V
15 L/B ATP warning lamp ATP indicator lamp: ON 0V
ATP indicator lamp: OFF Battery voltage
16 Y/R Power supply Ignition switch: ON Battery voltage
Ignition switch: OFF 0V
18 O 4WD shift switch
(4H) Ignition switch: ON4WD shift switch: 4H Battery voltage
4WD shift switch: 2WD, AUTO or 4LO 0V
19 L Clutch pressure solenoid
valve  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
21 BR 4WD shift indicator lamp
(AUTO indicator lamp)  AUTO indicator lamp of 4WD shift indicator lamp: OFF Battery voltage
AUTO indicator lamp of 4WD shift indicator lamp: ON 0V
22 Y/R Power supply Ignition switch: ON Battery voltage
Ignition switch: OFF 0V
23 R 4WD shift switch
(4LO)
Ignition switch: ON4WD shift switch: 4LO Battery voltage
4WD shift switch: 2WD, AUTO or 4H 0V
24 LG/R 4WD shift switch
(AUTO)
Ignition switch: ON4WD shift switch: AUTO Battery voltage
4WD shift switch: 2WD, 4H or 4LO 0V
Te r m i n a l
Wire
color Item Condition Data (Approx.)
Revision: December 20092009 QX56

TRANSFER CONTROL UNITDLN-87
< ECU DIAGNOSIS > [ATX14B]
C
EF
G H
I
J
K L
M A
B
DLN
N
O P
25 V Neutral-4LO switch  Vehicle stopped
 Engine running
 A/T selector lever
“N” position
 Brake pedal de- pressed 4WD shift switch: 2WD, AUTO or 4H Battery voltage
4WD shift switch: 4H to 4LO (While actua-
tor motor is operating.)
Battery voltage
→
0V
4WD shift switch: 4LO to 4H (While actua-
tor motor is operating.) 0V
→ Battery
voltage
4WD shift switch: 4LO 0V
27 W/L Actuator position switch 2
(High)  Vehicle stopped
 Engine running
 A/T selector lever
“N” position
 Brake pedal de-
pressed 4WD shift switch: 4H, AUTO or 2WD 0V
4WD shift switch: 4LO Battery voltage
28 B/G Sensor ground Always 0V
29 L/W Ignition switch monitor Ignition switch: ON Battery voltage
Ignition switch: OFF 0V
30 SB Shut off relay Ignition switch: ON 0V
Ignition switch: OFF Battery voltage
31 G Transfer fluid temperature
sensor
Ignition switch: ONTransfer fluid temperature approx. 20
°C
(68 °F) 1.1V
Transfer fluid temperature approx. 80 °C
(176 °F) 0.3V
33 R/L Transfer shift high relay
monitor  Vehicle stopped
 Engine running
 A/T selector lever
“N” position
 Brake pedal de- pressed 4WD shift switch: 4H to 4LO (“Wait” func-
tion is operating.)
Battery voltage
Except the above 0V
34 BR Clutch pressure switch  Vehicle stopped
 Engine running
 A/T selector lever
“D” position 4WD shift switch: AUTO or 4H (“Wait” func-
tion is not operating.)
0V
 Vehicle stopped
 Engine running 4WD shift switch: 2WD (“Wait” function is
not operating.)
Battery voltage
35 BR/
W Line pressure switch  Ignition switch: ON
 A/T selector lever “D” position
 4WD shift switch: AUTO
0V
 After the vehicle has been left at
room temperature
for 5 minutes and
more with ignition
switch in “OFF” po-
sition.  Ignition switch: ON
 A/T selector lever: “P” or "N" position
 4WD shift switch: other than AUTO
Battery voltage
40 L/Y ATP switch  Vehicle stopped
 Engine running
 A/T selector lever
“N”
 Brake pedal de- pressed 4WD shift switch: 4H to 4LO or 4LO to 4H
(While actuator motor is operating.)
0V
Except the above Battery voltage
Te r m i n a l
Wire
color Item Condition Data (Approx.)
Revision: December 20092009 QX56

DLN-88
< ECU DIAGNOSIS >[ATX14B]
TRANSFER CONTROL UNIT
CAUTION:
When using a circuit tester to measure voltage for inspection, be sure not to extend forcibly any connector terminals.
NOTE:
Data are reference value and are measured between each terminal and ground.
41 RTransfer motor relay moni-
tor  Accelerator pedal
depressed
 Vehicle stopped
 Engine running
 Brake pedal de- pressed 4WD shift switch: 2WD 0V
4WD shift switch: AUTO or 4LO (A/T selec-
tor lever “P” or “N” position)
0V
(Battery volt-
age for approx.
2 sec. after
shifting to “P”
and “N”.)
4WD shift switch: AUTO or 4LO (Except for
A/T selector lever “P” or “N” position) Battery voltage
4WD shift switch: 4H (A/T selector lever
“P” position) 0V
(Battery volt-
age for approx.
2 sec. after
shifting to “P”.)
4WD shift switch: 4H (Except for A/T selec-
tor lever “P” position) Battery voltage
42 P/G Transfer shift low relay
monitor  Vehicle stopped
 Engine running
 A/T selector lever
“N” position
 Brake pedal de-
pressed 4WD shift switch: 4LO to 4H (“Wait” func-
tion is operating.)
Battery voltage
Except the above 0V
43 G/Y Wait detection switch  Vehicle stopped
 Engine running
 A/T selector lever
“N” position
 Brake pedal de- pressed 4WD shift switch: 2WD, AUTO or 4H Battery voltage
4WD shift switch: 4H to 4LO (While actua-
tor motor is operating.)
Battery voltage
→
0V
4WD shift switch: 4LO to 4H (While actua-
tor motor is operating.) 0V
→ Battery
voltage
4WD shift switch: 4LO 0V
44 LG/B Actuator position switch 1
(Low)  Vehicle stopped
 Engine running
 A/T selector lever
“N” position
 Brake pedal de- pressed 4WD shift switch: 4LO 0V
4WD shift switch: 2WD, AUTO or 4H Battery voltage
45 B Ground Always 0V
47 W Power supply
(Memory back-up) Ignition switch: ON Battery voltage
Ignition switch: OFF Battery voltage
Te r m i n a l
Wire
color Item Condition Data (Approx.)
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

DLN-100
< ECU DIAGNOSIS >[ATX14B]
TRANSFER CONTROL UNIT
8 AD converterAD converter system of transfer control unit is malfunction-
ing. Refer to
DLN-24.
9 Transfer 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-102
Flashing pattern Item Diagnostic item is detected when... Reference
Revision: December 20092009 QX56

DLN-102
< SYMPTOM DIAGNOSIS >[ATX14B]
4WD SYSTEM SYMPTOMS
SYMPTOM DIAGNOSIS
4WD SYSTEM SYMPTOMS
Symptom TableINFOID:0000000003772161
If 4WD warning lamp turns ON, perform self-diagnosis. Refer to
DLN-18, "CONSULT-III Function (ALL MODE AWD/4WD)".
NOTE:
 Light tight-corner braking symptom may occur depending on driving conditions in AUTO mode. This is not a
malfunction.
 Heavy tight-corner braking symptom occurs when vehicle is driven in the following conditions: 4WD shift
switch is 4H or 4LO, steering wheel is turned fully to either side.
Symptom Condition Reference page
4WD shift indicator lamp and 4LO indicator lamp do not turn ON
(4WD shift indicator lamp and 4LO indicator lamp check) Ignition switch: ON
DLN-103
4WD warning lamp does not turn ON
(4WD warning lamp check) Ignition switch: ON
DLN-105
4WD shift indicator lamp or 4LO indicator lamp does not change Engine running DLN-107
ATP warning lamp does not turn ON Engine runningDLN-109
4WD shift indicator lamp keeps flashing Engine running DLN-111
4WD warning lamp flashes rapidly (2 times/second) While drivingDLN-112
4WD warning lamp flashes slowly
(1 time/2 seconds)While driving
DLN-113
Heavy tight-corner braking symptom occurs
(See NOTE.)  While driving
AUTO mode
 Steering wheel is turned fully
to either side DLN-114
ATP switch does not operate Engine running
DLN-116
4WD system does not operate While drivingDLN-118
Revision: December 20092009 QX56