2009 INFINITI QX56 200

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-81, "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-130, "Removal and Installation"
.
Component InspectionINFOID:0000000003772137
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 k Ω
80 (176) 0.3 k Ω
WDIA0188E
Revision: December 20092009 QX56

P1826 TRANSFER FLUID TEMPERATURE
DLN-69
< COMPONENT DIAGNOSIS > [ATX14B]
C
EF
G H
I
J
K L
M A
B
DLN
N
O P
3. Check resistance between transfer terminal cord assembly ter- minals 2 and 3.
4. If the inspection results are abnormal replace the transfer fluid temperature sensor. Refer to DLN-16, "Component Parts Loca-
tion".
Temperature °C ( °F) Resistance (Approx.)
20 (68) 2.5 k Ω
80 (176) 0.3 k Ω
WDIA0188E
Revision: December 20092009 QX56

DLN-70
< COMPONENT DIAGNOSIS >[ATX14B]
P1827 CLUTCH PRESSURE SWITCH
P1827 CLUTCH PRESSURE SWITCH
DescriptionINFOID:0000000003772138
Improper signal from the clutch pressure switch is i
nput due to open or short circuit. Also, a malfunction may
have occured in clutch pressure switch or hydraulic circuit.
DTC LogicINFOID:0000000003772139
DTC DETECTION LOGIC
DTC CONFIRMATION PROCEDURE
1.DTC CONFIRMATION PROCEDURE
1. Turn ignition switch ON.
2. Perform self-diagnosis.
Is DTC P1827 displayed?
YES >> Perform diagnosis procedure. Refer to DLN-70, "Diagnosis Procedure".
NO >> Inspection End.
Diagnosis ProcedureINFOID:0000000003772140
1.CHECK CLUTCH PRESSURE SWITCH SIGNAL
With CONSULT-III1. Start engine.
2. Select DATA MONITOR mode for A LL MODE AWD/4WD with CONSULT-III.
3. Read out ON/OFF switching action of the CL PRES SW while operating 4WD shift switch.
Without CONSULT-III
1. Start engine.
2. Check voltage between transfer control unit harness connector
terminals and ground.
Are inspection results normal?
DTC CONSULT-III Diagnostic item is detected when... Reference
[P1827] CLUTCH PRES SW  Improper signal from clutch pressure
switch is input due to open or short cir-
cuit.
 Malfunction occurs in clutch pressure switch or hydraulic circuit. Refer to
DLN-70
.
Condition Display value
 Ignition switch: ON
 A/T selector lever D posi- tion 4WD shift switch: AUTO or 4H (Wait
function is not operating.)
ON
Ignition switch: ON 4WD shift switch: 2WD (Wait func-
tion is not operating.) OFF
Connector Terminal Condition Voltage
(Approx.)
E143 34 -
Ground  Ignition switch: ON
 A/T selector lever D
position 4WD shift switch:
AUTO or 4H (Wait
function is not op-
erating.)
0V
Ignition switch: ON 4WD shift switch:
2WD (Wait function
is not operating.)Battery
voltage
SDIA2746E
Revision: December 20092009 QX56

P1827 CLUTCH PRESSURE SWITCHDLN-71
< COMPONENT DIAGNOSIS > [ATX14B]
C
EF
G H
I
J
K L
M A
B
DLN
N
O P
YES >> GO TO 5.
NO >> GO TO 2.
2.CHECK HARNESS BETWEEN TRAN SFER CONTROL UNIT AND CLUTCH PRESSURE SWITCH
1. Turn ignition switch OFF. (Stay for at least 5 seconds.)
2. Disconnect transfer control unit harness connector and the transfer terminal cord assembly harness con-
nector.
3. Check continuity between transfer control unit harness connec- tor E143 terminal 34 and transfer terminal cord assembly har-
ness connector F56 terminal 7
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 CONTROL UNIT
Check transfer control unit input/output signal. Refer to DLN-81, "Reference Value"
.
Are inspection results normal?
YES >> GO TO 4.
NO >> Check transfer control unit pin terminals fo r damage or loose connection with the harness connec-
tor. If any items are damaged, repair or replace damaged parts.
4.CHECK CLUTCH PRESSURE SWITCH
1. Turn ignition switch OFF. (Stay for at least 5 seconds.)
2. Remove clutch pressure switch. Refer to DLN-16, "Component Parts Location"
.
3. Push and release clutch pressure switch and check continuity
between terminal 7 and ground.
Are inspection results normal?
YES >> GO TO 5.
NO >> Replace clutch pressure switch.
5.CHECK DTC
Perform the self-diagnosis, after driving a vehicle for a while.
Are inspection results normal?
YES >> GO TO 6.
NO >> Replace transfer control unit. Refer to DLN-130, "Removal and Installation"
.
6.CRUISE TEST
Perform cruise test. Refer to DLN-7, "Preliminary Check"
.
Are inspection results normal?
YES >> Inspection End.
NO >> Perform the applicable trouble diagnosis.
Component InspectionINFOID:0000000003772141
1. Turn ignition switch OFF. (Stay for at least 5 seconds.)
2. Remove clutch pressure switch. Refer to DLN-16, "Component Parts Location"
.
Continuity should exist.
SDIA2747E
Terminal Condition Continuity
7 -
Ground Push clutch pressure switch Yes
Release clutch pressure switch No
WDIA0171E
Revision: December 20092009 QX56

DLN-72
< COMPONENT DIAGNOSIS >[ATX14B]
P1827 CLUTCH PRESSURE SWITCH
3. Push and release clutch pressure switch and check continuity
between terminal 7 and ground.
4. If the inspection results are abnormal replace the clutch pres- sure switch.
Terminal Condition Continuity
7 - Ground Push clutch pressure switch Yes
Release clutch pressure switch No
WDIA0171E
Revision: December 20092009 QX56

P1828 LINE PRESSURE SWITCHDLN-73
< COMPONENT DIAGNOSIS > [ATX14B]
C
EF
G H
I
J
K L
M A
B
DLN
N
O P
P1828 LINE PRESSURE SWITCH
DescriptionINFOID:0000000003772142
Improper signal from line pressure switch is input due to open or short circuit. Also, a malfunction may have
occured in the line pressure switch or hydraulic circuit.
DTC LogicINFOID:0000000003772143
DTC DETECTION LOGIC
DTC CONFIRMATION PROCEDURE
1.DTC CONFIRMATION PROCEDURE
1. Turn ignition switch ON.
2. Perform self-diagnosis.
Is DTC P1828 displayed?
YES >> Perform diagnosis procedure. Refer to DLN-73, "Diagnosis Procedure".
NO >> Inspection End.
Diagnosis ProcedureINFOID:0000000003772144
1.CHECK LINE PRESSURE SWITCH SIGNAL
With CONSULT-III1. Start engine.
2. Select DATA MONITOR mode for ALL MODE AWD/4WD with CONSULT-III.
3. Read out ON/OFF switching action of LINE PRES SW while operating 4WD shift switch.
Without CONSULT-III
1. Start engine.
2. Check voltage between transfer control unit harness connector
terminals and ground.
DTC CONSULT-III Diagnostic item is detected when... Reference
[P1828] LINE PRES SW  Improper signal from line pressure
switch is input due to open or short cir-
cuit.
 Malfunction occurs in line pressure switch or hydraulic circuit. Refer to
DLN-73
.
Condition Display value
 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
SDIA2751E
Revision: December 20092009 QX56

DLN-74
< COMPONENT DIAGNOSIS >[ATX14B]
P1828 LINE PRESSURE SWITCH
Are inspection results normal?
YES >> GO TO 5.
NO >> GO TO 2.
2.CHECK HARNESS BETWEEN TRANSFER CONT
ROL UNIT AND LINE PRESSURE SWITCH
1. Turn ignition switch OFF. (Stay for at least 5 seconds.)
2. Disconnect transfer control unit harness connector and the transfer terminal cord assembly harness con-
nector.
3. Check continuity between transfer control unit harness connec-
tor E143 terminal 35 and transfer terminal cord assembly har-
ness connector F56 terminal 1.
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 CONTROL UNIT
Check transfer control unit input/output signal. Refer to DLN-81, "Reference Value"
.
Are inspection results normal?
YES >> GO TO 4.
NO >> Check the following. If any items are damaged, repair or replace damaged parts.  Transfer control unit pin terminals for damage or loose connection with harness connector.
 Transfer control unit. Refer to DLN-130, "Removal and Installation"
.
4.CHECK LINE PRESSURE SWITCH
1. Turn ignition switch OFF. (Stay for at least 5 seconds.)
2. Remove line pressure switch. Refer to DLN-16, "Component Parts Location"
.
3. Push and release line pressure switch and check continuity between terminal 1 and ground.
Are inspection results normal?
YES >> GO TO 5.
NO >> Replace line pressure switch.
5.CHECK DTC
Perform the self-diagnosis, after driving a vehicle for a while.
Connector Terminal Condition Voltage
(Approx.)
E143 35 -
Ground  A/T selector lever D
position 4WD shift switch:
AUTO
0V
 Except the above
 The vehicle has been left at room
temperature for 5
minutes and more
with ignition switch
in OFF position.  Ignition switch:
ON
 A/T selector le-
ver: P or N posi-
tion
 4WD shift
switch: other
than AUTO Battery
voltage
Continuity should exist.
SDIA2752E
Terminal Condition Continuity
1 -
Ground Push line pressure switch Yes
Release line pressure switch No
WDIA0172E
Revision: December 20092009 QX56

P1828 LINE PRESSURE SWITCHDLN-75
< COMPONENT DIAGNOSIS > [ATX14B]
C
EF
G H
I
J
K L
M A
B
DLN
N
O P
Are inspection results normal?
YES >> GO TO 6.
NO >> Replace transfer control unit. Refer to DLN-130, "Removal and Installation"
.
6.CRUISE TEST
Perform cruise test. Refer to DLN-7, "Preliminary Check"
.
Are inspection results normal?
YES >> Inspection End.
NO >> Perform the applicable trouble diagnosis.
Component InspectionINFOID:0000000003772145
1. Turn ignition switch OFF. (Stay for at least 5 seconds.)
2. Remove line pressure switch. Refer to DLN-16, "Component Parts Location"
.
3. Push and release line pressure switch and check continuity between terminal 1 and ground.
4. If the inspection results are abnormal, replace the line pressure switch.
Terminal Condition Continuity
1 - Ground Push line pressure switch Yes
Release line pressure switch No
WDIA0172E
Revision: December 20092009 QX56