2010 INFINITI QX56 engine

DLN-88
< ECU DIAGNOSIS >[ATX14B]
TRANSFER CONTROL UNIT
CAUTION:
When using a circuit tester to measure voltage for inspecti
on, 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 Always0V
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
ConditionData (Approx.)
Revision: April 20092010 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-25
.
[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-27
.
[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-28
.
[P1809] CONTROL UNIT 4 AD converter system of transfer control unit is mal-
functioning. Refer to DLN-25
.
[P1810] 4L POSI SW TF Improper signal from neutral-4LO switch is input due
to open or short circuit. Refer to DLN-29
.
[ 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-32
.
[P1814] 4WD DETECT SWITCH Improper signal from wait detection switch is input
due to open or short circuit. Refer to DLN-36
.
[P1816] PNP SW/CIRC When transmission range switch signal is malfunc-
tion or communication error between the control
units. Refer to DLN-39
.
[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-40
.
[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-46
.
[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-49
.
[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-53
.
[P1822] DUTY SOLENOID Proper voltage is not applied to clutch pressure so-
lenoid valve due to open or short circuit. Refer to DLN-54
.
[P1823] 2-4WD SOLENOID Proper voltage is not applied to 2-4WD solenoid
valve due to open or short circuit. Refer to DLN-58
.
[P1824] MOTOR RELAY Motor does not operate properly due to open or
short circuit in transfer motor or transfer motor relay.
Refer to DLN-62
.
Revision: April 20092010 QX56

DLN-100
< 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-68.
10 Neutral-4LO switch Improper signal from neutral-4LO switch is input due to
open or short circuit. Refer to DLN-29
.
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-71
.
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-74
.
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-53
.
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-77
.
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-32
.
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-78
.
18 Wait detection switch Improper signal from wait detection switch is input due to
open or short circuit.
Refer to DLN-36
.
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-40
.
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-46
.
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-49
.
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-79
.
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-80
.
24 Transmission range
switch signal (from
TCM) When transmission range switch signal is malfunction or
communication error between the vehicles.
Refer to DLN-39
.
Repeats flickering
every 2 to 5 sec. — System normal. Refer to DLN-102
Flashing pattern
ItemDiagnostic item is detected when... Reference
Revision: April 20092010 QX56

DLN-102
< SYMPTOM DIAGNOSIS >[ATX14B]
4WD SYSTEM SYMPTOMS
SYMPTOM DIAGNOSIS
4WD SYSTEM SYMPTOMS
Symptom TableINFOID:0000000005148856
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 ConditionReference 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 runningDLN-107
ATP warning lamp does not turn ON Engine runningDLN-109
4WD shift indicator lamp keeps flashing Engine runningDLN-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 runningDLN-116
4WD system does not operate While drivingDLN-118
Revision: April 20092010 QX56

4WD WARNING LAMP DOES NOT TURN ONDLN-105
< SYMPTOM DIAGNOSIS > [ATX14B]
C
EF
G H
I
J
K L
M A
B
DLN
N
O P
4WD WARNING LAMP DOES NOT TURN ON
DescriptionINFOID:0000000005148859
4WD warning lamp does not turn ON when turning ignition switch to ON.
Diagnosis ProcedureINFOID:0000000005148860
Regarding Wiring Diagram information, refer to DLN-89, "Wiring Diagram - ALL-MODE 4WD SYSTEM -".
1.CHECK TRANSFER CONTROL UNIT POWER SUPPLY AND GROUND CIRCUITS
Refer to DLN-22, "
Diagnosis Procedure".
Are the inspection results normal?
YES >> GO TO 2.
NO >> Repair as necessary.
2.CHECK COMBINATION METER POWER SUPPLY AND GROUND CIRCUITS
Refer to MWI-28, "
COMBINATION METER : Diagnosis Procedure".
Are the inspection results normal?
YES >> GO TO 3.
NO >> Perform repairs as necessary.
3.CHECK HARNESS BETWEEN TR ANSFER CONTROL UNIT AND COMBINATION METER
1. Turn ignition switch OFF. (Stay for at least 5 seconds.)
2. Disconnect transfer control unit and combination meter harness connectors.
3. Check continuity between the following terminals.
- Transfer control unit harness connector E142 (A) terminal 5 and combination meter harness connector M23 (B) terminal 49.
Also check harness for short to ground and short to power.
Are the inspection results normal?
YES >> GO TO 4.
NO >> Repair or replace damaged parts.
4.CHECK INDICATOR LAMP CIRCUIT
1. Connect combination meter harness connector.
2. Turn ignition switch ON. (Do not start engine.)
3. Ground the following terminal using suitable wiring.
- Transfer control unit harness connector E142 terminal 5 and ground.
Does 4WD warning lamp turn on?
YES >> GO TO 5.
NO >> Replace combination meter. Refer to MWI-100,
"Removal and Installation".
5.SYMPTOM CHECK
Check again.
Are the inspection results normal?
YES >> Inspection End. Continuity should exist.
AWDIA0187ZZ
SDIA2774E
Revision: April 20092010 QX56

DLN-110
< SYMPTOM DIAGNOSIS >[ATX14B]
ATP WARNING LAMP DOES NOT TURN ON
- Transfer control unit harness
connector E143 (B) terminal 40
and combination meter harness connector M23 (A) terminal 44.
Also check harness for short to ground and short to power.
Are the inspection results normal?
YES >> GO TO 6.
NO >> Repair or replace damaged parts.
6.CHECK ATP WARNING LAMP CIRCUIT
1. Place A/T selector lever in P position.
2. Connect combination meter harness connector and transfer control unit harness connector.
3. Disconnect ATP switch harness connector.
4. Ground the following terminal using suitable wiring.
- ATP switch harness connector F55 terminal 8 and ground.
5. Turn ignition switch ON. (Do not start engine.)
Does indicator lamp turn on?
YES >> GO TO 7.
NO >> Replace combination meter. Refer to MWI-100,
"Removal and Installation".
7.SYMPTOM CHECK
Check again.
Are the inspection results normal?
YES >> Inspection End.
NO >> GO TO 8.
8.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 9.
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.
9.CHECK TRANSFER INNER PARTS
1. Disassemble transfer assembly. Refer to DLN-142, "
Disassembly and Assembly".
2. Check transfer inner parts.
Are the inspection results normal?
YES >> Inspection End.
NO >> Repair or replace damaged parts. 40 to 44: Continuity should not exist.
44 to 40: Continuity should exist.
AWDIA0186ZZ
SDIA2769E
Revision: April 20092010 QX56

DLN-114
< SYMPTOM DIAGNOSIS >[ATX14B]
HEAVY TIGHT-CORNER BRAKING SYMPTOM OCCURS
HEAVY TIGHT-CORNER BR
AKING SYMPTOM OCCURS
DescriptionINFOID:0000000005148871
This symptom occurs when the vehicle is accelerati ng in 4WD and the steering wheel is turned fully either
direction. It may feel like a bump or being pushed fr om behind. A small amount of this bumping feeling is
acceptable under certain road conditions. The transfer case may be adjusted using the CONSULT-III to com-
pensate for this condition.
Diagnosis ProcedureINFOID:0000000005148872
DIAGNOSTIC PROCEDURE
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.
1.CHECK SYSTEM FOR CAN COMMUNICATION LINE
Perform self-diagnosis. Refer to DLN-18, "
CONSULT-III Function (ALL MODE AWD/4WD)".
Is CAN COMM CIRCUIT [U1000] displayed?
YES >> Perform trouble diagnosis for CAN communication line.
NO >> GO TO 2.
2.CHECK SYSTEM FOR 4WD SHIFT SWITCH
Perform trouble diagnosis for 4WD shift switch system. Refer to DLN-32, "
Diagnosis Procedure".
Are the inspection results normal?
YES >> GO TO 3.
NO >> Repair or replace damaged parts.
3.CHECK ACCELERATOR PEDAL POSITION SIGNAL CIRCUIT
Perform self diagnosis for ECM. Refer to EC-63, "
CONSULT-III Function (ENGINE)".
Is any malfunction deteced by self-diagnosis?
YES >> Check the malfunctioning system.
NO >> GO TO 4.
4.CHECK SYSTEM FOR CLUT CH PRESSURE SOLENOID
Perform trouble diagnosis for clutch pressure solenoid system. Refer to DLN-71, "
Diagnosis Procedure".
Are the inspection results normal?
YES >> GO TO 5.
NO >> Repair or replace damaged parts.
5.SYMPTOM CHECK
Check again.
Are the inspection results normal?
YES >> Inspection End.
NO >> GO TO 6.
6.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 7.
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.
7.CHECK TRANSFER INNER PARTS
1. Disassemble transfer assembly. Refer to DLN-142, "
Disassembly and Assembly".
2. Check transfer inner parts.
Revision: April 20092010 QX56

DLN-116
< SYMPTOM DIAGNOSIS >[ATX14B]
ATP SWITCH
ATP SWITCH
DescriptionINFOID:0000000005148873
The ATP indicator is ON when the transfer case is not in neutral.
Diagnosis ProcedureINFOID:0000000005148874
Regarding Wiring Diagram information, refer to
DLN-89, "Wiring Diagram - ALL-MODE 4WD SYSTEM -".
1.CHECK ATP SWITCH 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 ATP SWITCH.
Without CONSULT-III
1. Start engine.
2. Check voltage between transfer control unit harness connector
terminal and ground.
Are inspection results normal?
YES >> GO TO 5.
NO >> GO TO 2.
2.CHECK HARNESS BETWEEN TRANSFER CONTROL UNIT AND ATP SWITCH
1. Turn ignition switch OFF. (Stay for at least 5 seconds.)
2. Disconnect transfer control unit harness connector and the ATP switch harness connector.
3. Check continuity between transfer control unit harness connec- tor E143 terminal 40 and ATP switch harness connector F55 ter-
minal 8.
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.
Condition Display value
• 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.)
ON
Except the above OFF
Connector TerminalConditionVoltage
(Approx.)
E143 40 -
Ground • 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
SDIA2755E
Continuity should exist.
SDIA2756E
Revision: April 20092010 QX56