2006 INFINITI QX56 engine

TROUBLE DIAGNOSISTF-45
CE F
G H
I
J
K L
M A
B
TF
Revision: November 2009 2006 QX56
SELF-DIAG RESULT MODE
Operation Procedure
1. Perform “CONSULT-II SETTING PROCEDURE ”. Refer to TF-44, "CONSULT-II SETTING PROCEDURE"
.
2. With engine at idle, touch “SELF-DIAG RESULTS”.
Display shows malfunction experienced since the last erasing
operation.
NOTE:

The details for “TIME” are as follow:
–“0”: Error currently detected with transfer control unit.
–Except for “0”: Error detected in the past and memorized
with transfer control unit.
Detects frequency of driving after DTC occurs (frequency
of turning ignition switch “ON/OFF”).
Display Item List
SDIA2687E
Items (CONSULT-II screen
terms) Diagnostic item is detected when...
Check item
CONTROL UNIT 1
[P1802]

Malfunction is detected in the memory (RAM) system of transfer
control unit. TF-57, "Transfer Control Unit"
CONTROL UNIT 2
[P1803]
Malfunction is detected in the memory (ROM) system of transfer
control unit.TF-57, "Transfer Control Unit"
CONTROL UNIT 3
[P1804]
Malfunction is detected in the memory (EEPROM) system of
transfer control unit.TF-57, "Transfer Control Unit"
VHCL SPEED SEN
·AT
[P1807]
Malfunction is detected in output shaft revolution signal that is
output from TCM through CAN communication.

Improper signal is input while driving. TF-58, "
Output Shaft Revolution
Signal (TCM)"
VHCL SPEED SEN
·ABS
[P1808]

Malfunction is detected in vehicle speed signal that is output from
ABS actuator and electric unit (control unit) through CAN commu-
nication.

Improper signal is input while driving. TF-58, "
Vehicle Speed Sensor
(ABS)"
CONTROL UNIT 4
[P1809]
AD converter system of transfer control unit is malfunctioning.
TF-57, "Transfer Control Unit"
4L POSI SW TF
[P1810]
Improper signal from neutral-4LO switch is input due to open or
short circuit.TF-59, "Neutral-4LO Switch"
BATTERY VOLTAGE
[P1811]
Power supply voltage for transfer control unit is abnormally low
while driving.TF-54, "Power Supply Circuit For
Transfer Control Unit"
4WD MODE SW
[P1813]
More than two switch inputs are simultaneously detected due to
short circuit of 4WD shift switch.
TF-62, "4WD Shift Switch"
4WD DETECT SWITCH
[P1814]
Improper signal from wait detection switch is input due to open or
short circuit.
TF-66, "Wait Detection Switch"
PNP SW/CIRC
[P1816]
When A/T PNP switch signal is malfunction or communication
error between the vehicles.TF-69, "PNP Switch Signal
(TCM)"
SHIFT ACTUATOR
[P1817]

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.TF-70, "
Actuator Motor"
SHIFT ACT POSI SW
[P1818]
Improper signal from actuator position switch is input due to open
or short circuit.

Malfunction is detected in the actuator position switch.
TF-77, "
Actuator Position
Switch"

TF-46
TROUBLE DIAGNOSIS
Revision: November 20092006 QX56
CAUTION:

If “CAN COMM CIRCUIT [U1000]” is displayed with other DTCs, first perform the trouble diagnosis for CAN communica-
tion line.

If “VHCL SPEED SEN·AT [P1808]”, “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 [P1808]”, is displayed, first perform the trouble diagnosis for A/T system.
NOTE:

If "SHIFT ACT POSI SW [P1818]" or “SHIFT ACT CIR [P1819] ” is displayed, 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 ” posi-
tion on A/T PNP switch. When there is nothing wrong with the electrical system, check the hydraulic system.
SHIFT ACT CIR
[P1819]

Transfer control device actuator circuit is shorted or open. (Mal-
functions 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.
TF-81, "
Transfer Control Device"
Malfunction is detected in transfer shut off relay.
TF-54, "Power Supply Circuit For
Transfer Control Unit"
ENGINE SPEED SIG
[P1820]
Malfunction is detected in engine speed signal that is output from
ECM through CAN communication.

Improper signal is input while driving.TF-85, "
Engine Speed Signal
(ECM)"
DUTY SOLENOID
[P1822]
Proper voltage is not applied to clutch pressure solenoid valve
due to open or short circuit.
TF-86, "Clutch Pressure Sole-
noid"
2-4WD SOLENOID
[P1823]
Proper voltage is not applied to 2-4WD solenoid valve due to
open or short circuit.
TF-91, "2-4WD Solenoid"
MOTOR RELAY
[P1824]
Motor does not operate properly due to open or short circuit in
transfer motor or motor relay.TF-95, "Transfer Motor"
OIL TEMP SEN
[P1826]
Signal voltage from fluid temperature sensor is abnormally high
(Transfer fluid temperature is abnormally low) while driving.TF-102, "Transfer Fluid Temper-
ature"
CLUTCH PRES SW
[P1827]
Improper signal from clutch pressure switch is input due to open
or short circuit.

Malfunction occurs in clutch pressure switch or hydraulic circuit.TF-105, "
Clutch Pressure
Switch"
LINE PRES SW
[P1828]
Improper signal from line pressure switch is input due to open or
short circuit.

Malfunction occurs in line pressure switch or hydraulic circuit.
TF-108, "
Line Pressure Switch"
THROTTLE POSI SEN
[P1829]

Malfunction is detected in accelerator pedal position signal that is
output from ECM through CAN communication.

Signal voltage from accelerator pedal position sensor is abnor-
mally high or low.TF-111, "
Throttle Position Signal
(ECM)"
ABS OP SIG
[P1830]
Malfunction is detected in ABS operation signal that is output
from ABS actuator and electric unit (control unit) through CAN
communication.
TF-111, "ABS Operation Signal
(ABS)"
VDC OP SIG
[P1831]
Malfunction is detected in VDC operation signal that is output
from ABS actuator and electric unit (control unit) through CAN
communication.TF-112, "VDC Operation Signal
(ABS)"
TCS OP SIG
[P1832]
Malfunction is detected in TCS operation signal that is output
from ABS through CAN communication.
TF-112, "TCS Operation Signal
(ABS)"
CAN COMM CIRCUIT
[U1000]
Malfunction has been detected from CAN communication line.
TF-113, "CAN Communication
Line"
NO DTC IS DETECTED.
FURTHER TESTING MAY
BE REQUIRED.

No NG item has been detected.
—
Items (CONSULT-II screen
terms) Diagnostic item is detected when...
Check item

TROUBLE DIAGNOSISTF-47
CE F
G H
I
J
K L
M A
B
TF
Revision: November 2009 2006 QX56
How to Erase Self-diagnostic Results
1. Perform applicable inspection of malfunctioning item and then repair or replace.
2. Start engine and select “SELF-DIAG RESULTS” mode for “ALL MODE AWD/4WD ” with CONSULT-II.
3. Touch “ERASE” on CONSULT-II screen to erase DTC memory.
CAUTION:
If memory cannot be erased, perform applicable diagnosis.
DATA MONITOR MODE
Operation Procedure
1. Perform “CONSULT-II SETTING PROCEDURE ”. Refer to TF-44, "CONSULT-II SETTING PROCEDURE"
.
2. Touch “DATA MONITOR ”.
3. Select from “SELECT MONITOR ITEM ”, screen of data monitor mode is displayed.
NOTE:
When malfunction is detected, CONSULT-II performs REAL-TIME DIAGNOSIS.
Also, any malfunction detected while in this mode will be displayed at real time.
Display Item List
× : Standard –: Not applicable
Monitored item (Unit) Monitor item selection
Remarks
ECU INPUT
SIGNALS MAIN
SIGNALS SELEC-
TION FROM
MENU
VHCL/S SEN ·FR [km/h] or [mph] ×–×Wheel speed calculated by ABS actuator and
electric unit (control unit).
Signal input with CAN communication line.
VHCL/S SEN ·RR [km/h] or [mph] ×–×Wheel speed calculated by TCM.
Signal input with CAN communication line.
ENGINE SPEED [rpm] ×–×Engine speed calculated by ECM.
Signal input with CAN communication line.
THRTL POS SEN [V] ×–×Accelerator pedal position (APP) sensor sig-
nal voltage is displayed.
Signal input with CAN communication line.
FLUID TEMP SE [V] ×–×Transfer fluid temperature sensor signal volt-
age is displayed.
BATTERY VOLT [V] ×–×Power supply voltage for transfer control unit.
2WD SWITCH [ON/OFF] ×–×4WD shift switch status is displayed.
AUTO SWITCH [ON/OFF] ×–×4WD shift switch status is displayed.
LOCK SWITCH [ON/OFF] ×–×4WD shift switch status is displayed.
(LOCK means 4H of 4WD shift switch.)
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] זד
N ” position signal of A/T PNP switch status
is displayed.
Signal input with CAN communication line.
R POSI SW AT [ON/OFF] זד
R ” position signal of A/T PNP switch status
is displayed.
Signal input with CAN communication line.

TF-50
TROUBLE DIAGNOSIS
Revision: November 20092006 QX56
Clutch Force Release Limit Adjustment
1. Current CLUTCH FORCE RELEASE LIMIT value “0.3 kgm”
appears under “CONDITION SETTING ” on CONSULT-II display.
2. Touch “1.2” on the display.
3. Display changes to “NOW ADJUSTING” in a short time.
4. When clutch force release limit value is set to “1.2 kgm”, current
value “0.3 kgm ” shown on display will be replaced by “1.2 kgm”
and “ADJUSTMENT COMPLETE ” will appear at the same time.
Clutch force release limit value setting is now complete.
Self-diagnostic ProcedureEDS002HL
SELF-DIAGNOSTIC PROCEDURE (WITH CONSULT-II)
Refer to TF-45, "SELF-DIAG RESULT MODE" .
SELF-DIAGNOSTIC PROCEDURE (WITHOUT CONSULT-II)
Description
If the engine starts when there is something wrong with the 4WD system, the 4WD warning lamp turns ON or
flickers in the combination meter. When the system functions properly, the warning lamp turns ON when the
ignition switch is turned to “ON”, and it turns OFF after engine starts. To locate the cause of a problem, start
the self-diagnosis function. The 4WD warning lamp in the combination meter will indicate the problem area by
flickering according to the self-diagnostic results. As for the details of the 4WD warning lamp flickering pat-
terns, refer to TF-51, "
Diagnostic Procedure" .
1.2 kg-m : Tight corner braking symptom is allevi-
ated. However, vibration may occur when
accelerating on a low µ road (icy road, etc.).
0.3 kg-m : Initial set value.
0.2 kg-m : Do not set to this value because the tight corner braking symptom will get worse.
SMT968D
SMT969D
SMT970D

TROUBLE DIAGNOSISTF-51
CE F
G H
I
J
K L
M A
B
TF
Revision: November 2009 2006 QX56
Diagnostic Procedure
1. Warm up engine.
2. Move A/T selector lever to “P” position.
3. Turn 4WD shift switch to “2WD” position.
4. Turn ignition switch “ON” and “OFF ” at least twice, and then turn ignition switch “OFF”.
5. Turn 4WD shift switch to “AUTO” position.
6. Turn ignition switch “ON”. (Do not start engine.)
7. 4WD warning lamp ON. If 4WD warning lamp does not turn ON, refer to TF-121, "
4WD Warning Lamp Does Not Turn ON" .
8. Move A/T selector lever to “R” position.
9. Turn 4WD shift switch to “2WD”, “AUTO ” and “2WD ” in order.
10. Move A/T selector lever to “D” position.
11. Turn 4WD shift switch to “4H”, “AUTO ” and “4H” in order.
12. Move A/T selector lever to “N” position.
13. Turn 4WD shift switch to “AUTO” position.
14. Move A/T selector lever to “P” position.
15. Read the flickering of 4WD warning lamp. Refer to TF-51, "
Judgement Self-diagnosis" .
Judgement Self-diagnosis
When a malfunction is detected, the malfunction route is indicated by flickering of the 4WD warning lamp.
PDIA0227E
Flickering pattern or
flickering condition Items
Malfunction Check items
2 Output shaft revolution
signal (from TCM)

Malfunction is detected in output shaft revolution signal
that is output from TCM through CAN communication.

Improper signal is input while driving. TF-58, "
Output Shaft
Revolution Signal
(TCM)"
3
Clutch pressure sole-
noid signal
Proper voltage is not applied to clutch pressure solenoid
valve due to open or short circuit. TF-86, "Clutch Pres-
sure Solenoid"
4
2-4WD solenoid signal
Proper voltage is not applied to 2-4WD solenoid valve
due to open or short circuit. TF-91, "2-4WD Sole-
noid"
5
Transfer motor
Motor does not operate properly due to open or short cir-
cuit in transfer motor or motor relay. TF-95, "Transfer Motor"
6
Vehicle speed signal
(from 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. TF-58, "
Vehicle Speed
Sensor (ABS)"
7
CAN communication
Malfunction has been detected from CAN communica-
tion line. TF-113, "CAN Commu-
nication Line"
8
AD converter
AD converter system of transfer control unit is malfunc-
tioning. TF-54, "Power Supply
Circuit For Transfer
Control Unit"

TF-52
TROUBLE DIAGNOSIS
Revision: November 20092006 QX56
9Transfer fluid tempera-
ture

Signal voltage from fluid temperature sensor is abnor-
mally high (Transfer fluid temperature is abnormally low)
while driving. TF-102, "Transfer Fluid
Temperature"
10
Neutral-4LO switch
Improper signal from neutral-4LO switch is input due to
open or short circuit. TF-59, "Neutral-4LO
Switch"
11
Clutch pressure switch

Improper signal from clutch pressure switch is input due
to open or short circuit.

Malfunction occurs in clutch pressure switch or hydraulic
circuit. TF-105, "
Clutch Pres-
sure Switch"
12
Line pressure switch

Improper signal from line pressure switch is input due to
open or short circuit.

Malfunction occurs in line pressure switch or hydraulic
circuit. TF-108, "
Line Pressure
Switch"
13
Engine speed signal
(from ECM)

Malfunction is detected in engine speed signal that is
output from ECM through CAN communication.

Improper signal is input while driving. TF-85, "
Engine Speed
Signal (ECM)"
14
Throttle position sen-
sor (from ECM)

Malfunction is detected in accelerator pedal position sig-
nal that is output from ECM through CAN communica-
tion.

Signal voltage from accelerator pedal position sensor is
abnormally high or low. TF-111, "
Throttle Posi-
tion Signal (ECM)"
15
Power supply
Power supply voltage for transfer control unit is abnor-
mally low while driving. TF-54, "Power Supply
Circuit For Transfer
Control Unit"
16
4WD shift switch
More than two switch inputs are simultaneously detected
due to short circuit of 4WD shift switch. TF-62, "4WD Shift
Switch"
17
ABS operation signal
(from ABS)

Malfunction is detected in ABS operation signal that is
output from ABS actuator and electric unit (control unit)
through CAN communication. TF-111, "ABS Operation
Signal (ABS)"
18
Wait detection switch
Improper signal from wait detection switch is input due to
open or short circuit. TF-66, "Wait Detection
Switch"
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. TF-70, "
Actuator
Motor", TF-54, "Power
Supply Circuit For
Transfer Control Unit"
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. TF-77, "
Actuator Posi-
tion Switch"
21
Actuator circuit

Transfer control device actuator circuit is shorted or
open. (Malfunctions are detected when motor relay cir-
cuit is open/shorted or relay transfer shift circuit is open/
shorted.)

Malfunction occurs in transfer control device drive circuit. TF-81, "
Transfer Con-
trol Device"

Malfunction is detected in transfer shut off relay.
TF-54, "
Power Supply
Circuit For Transfer
Control Unit"
22
VDC operation signal
(from VDC)

Malfunction is detected in VDC operation signal that is
output from ABS actuator and electric unit (control unit)
through CAN communication. TF-112, "VDC Opera-
tion Signal (ABS)"
23
TCS operation signal
(from TCS)

Malfunction is detected in TCS operation signal that is
output from ABS actuator and electric unit (control unit)
through CAN communication. TF-112, "TCS Opera-
tion Signal (ABS)"
Flickering pattern or
flickering condition Items
Malfunction Check items

TROUBLE DIAGNOSIS FOR SYSTEMTF-55
CE F
G H
I
J
K L
M A
B
TF
Revision: November 2009 2006 QX56
DIAGNOSTIC PROCEDURE
1. CHECK POWER SUPPLY
1. Turn ignition switch “OFF”. (Stay for at least 5 seconds.)
2. Connect transfer control unit harness connector.
3. Check voltage between transfer control unit harness connector terminals and ground.
4. Turn ignition switch “ON”. (Do not start engine.)
5. Check voltage between transfer control unit harness connector terminals and ground.
OK or NG
OK >> GO TO 2.
NG >> Check the following. If any items are damaged, repair or replace damaged parts.

10A fuses No. 26 located in fuse and fusible link box and No. 59 located in the fuse and relay
box. Refer to PG-4, "
POWER SUPPLY ROUTING CIRCUIT" .

20A fuse No. 53 located in the IPDM E/R. Refer to PG-4, "POWER SUPPLY ROUTING CIR-
CUIT" .

Harness for short or open between battery and transfer control unit harness connector termi-
nals 47.

Harness for short or open between battery and transfer control unit harness connector terminal
29.

Harness for short or open between battery and transfer shut off relay harness connector E69
terminal 1, and 3.

Harness for short or open between transfer shut off relay harness connector E69 terminal 2
and transfer control unit harness connector terminal 30.

Harness for short or open between transfer shut off relay harness connector E69 terminal 5
and transfer control unit harness connector terminals 16 and 22.

Battery and ignition switch. Refer to PG-4, "POWER SUPPLY ROUTING CIRCUIT" .

Transfer shut off relay. Refer to TF-57, "COMPONENT INSPECTION" .
ConnectorTerminal Voltage (Approx.)
E142 16 - Ground
0V
22 - Ground
E143 29 - Ground
30 - Ground
Battery voltage
47 - Ground
WDIA0165E
Connector Terminal Voltage (Approx.)
E142 16 - Ground
Battery voltage
22 - Ground
E143 29 - Ground
30 - Ground
0V
47 - Ground Battery voltage
WDIA0166E

TROUBLE DIAGNOSIS FOR SYSTEMTF-57
CE F
G H
I
J
K L
M A
B
TF
Revision: November 2009 2006 QX56
COMPONENT INSPECTION
1. Turn ignition switch “OFF”. (Stay for at least 5 seconds.)
2. Remove transfer shut off relay. Refer to TF-22, "
Location of Electrical Parts" .
3. Apply 12V direct current between transfer shut off relay termi- nals 1 and 2.
4. Check continuity between relay terminals 3 and 5.
5. If NG, replace the transfer shut off relay. Refer to TF-22, "
Loca-
tion of Electrical Parts" .
Transfer Control UnitEDS002I5
DIAGNOSTIC PROCEDURE
1. INSPECTION START
Do you have CONSULT-II?
YES or NO
YES >> GO TO 2.
NO >> GO TO 3.
2. PERFORM SELF-DIAGNOSIS (WITH CONSULT-II)
With CONSULT-II
1. Turn ignition switch “ON”. (Do not start engine.)
2. Select “SELF-DIAG RESULTS ” mode for “ALL MODE AWD/4WD ” with CONSULT-II.
3. Touch “ERASE”.
4. Turn ignition switch “OFF” and wait at least 10 seconds.
5. Perform the self-diagnosis again.
Is the
“CONTROL UNIT 1 [P1802]”, “CONTROL UNIT 2 [P1803]”, “CONTROL UNIT 3 [P1804]” or “CONTROL
UNIT 4 [P1809]” displayed?
YES >> Replace transfer control unit. Refer to TF-132, "Removal and Installation" .
NO >> Inspection End.
3. PERFORM SELF-DIAGNOSIS (WITHOUT CONSULT-II)
Without CONSULT-II
1. Perform the self-diagnosis and then erase self-diagnostic results. Refer to TF-50, "
SELF-DIAGNOSTIC
PROCEDURE (WITHOUT CONSULT-II)" and TF-53, "ERASE SELF-DIAGNOSIS" .
2. Perform the self-diagnosis again.
Do the self-diagnostic results indicate AD converter?
YES >> Replace transfer control unit. Refer to TF-132, "Removal and Installation" .
NO >> Inspection End.
Condition Continuity
12V direct current supply between terminals 1 and 2 Yes
OFF No
SCIA1245E