2005 INFINITI QX4 check engine

TF-34
TROUBLE DIAGNOSIS
Revision: October 20052005 QX56
CRUISE TEST
1. CHECK INPUT SIGNAL
1. Warm up engine to normal operating temperature.
2. Park vehicle on flat surface.
3. Move A/T selector lever to “P” position.
4. Set 4WD shift switch to “AUTO” position.
5. Start engine.
6. Drive vehicle for at least 30 seconds at a speed higher than 20 km/h (12 MPH).
Check 4WD warning lamp turned ON?
On steady>>Perform the self-diagnosis. Refer to TF-50, "SELF-DIAGNOSTIC PROCEDURE (WITH CON-
SULT-II)" (with CONSULT-II) or TF-50, "SELF-DIAGNOSTIC PROCEDURE (WITHOUT CON-
SULT-II)" (without CONSULT-II).
Flash rapidly>>GO TO TF-128, "
4WD Warning Lamp Flashes Rapidly" .
Flash slowly>>GO TO TF-129, "
4WD Warning Lamp Flashes Slowly" .
NO >> GO TO 2.
2. CHECK TIGHT CORNER BRAKING SYMPTOM (1)
1. Set 4WD shift switch to “AUTO” position.
2. Drive vehicle at speed lower than 20 km/h (12 MPH) with steering wheel fully turned.
Does tight corner braking symptom occur?
YES >> GO TO TF-130, "Heavy Tight-corner Braking Symptom Occurs" .
NO >> GO TO 3.
3. CHECK TIGHT CORNER BRAKING SYMPTOM (2)
1. Set 4WD shift switch to “4HI” position.
2. Drive vehicle at speed lower than 20 km/h (12 MPH) with steering wheel fully turned.
Does tight corner braking symptom occur?
YES >> Inspection End.
NO >> GO TO TF-131, "
4WD System Does Not Operate" .
Trouble Diagnosis Chart for SymptomsEDS002HI
If 4WD warning lamp turns ON, perform self-diagnosis. Refer to TF-50, "Self-diagnostic Procedure" .
Symptom Condition Check item 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: ONPower supply and ground for transfer
control unit
TF-117
Transfer shut off relay
Combination meter
4WD warning lamp does not turn ON
(4WD warning lamp check)Ignition switch: ONPower supply and ground for transfer
control unit
TF-121
Transfer shut off relay
Combination meter

TROUBLE DIAGNOSIS
TF-35
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Revision: October 20052005 QX56
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.
4WD shift indicator lamp or 4LO indicator
lamp does not changeEngine running4WD shift switch
TF-123
Wait detection switch
Neutral-4LO switch
ATP switch
2-4WD solenoid
Transfer control device
Actuator motor
Actuator position switch
Transfer inner parts
ATP warning lamp turns ON Engine runningCAN communication line
TF-125
4WD shift switch
PNP switch signal
ATP switch
Combination meter
Transfer inner parts
4LO indicator lamp repeats flashing Engine runningWait detection switch
TF-127
Neutral-4LO switch
Transfer inner parts
4WD warning lamp flashes rapidly (2 times/
second)While drivingTransfer fluid temperature
TF-128
Tire size is different between front and
rear of vehicle
4WD warning lamp flashes slowly
(1 time/2 seconds)While drivingTire size is different between front and
rear of vehicle.
TF-129
Transfer fluid temperature
Clutch pressure switch
Heavy tight-corner braking symptom occurs
(See NOTE.)

While driving

AUTO mode

Steering wheel is
turned fully to either
sideCAN communication line
TF-130
4WD shift switch
Accelerator pedal position signal
Clutch pressure solenoid
Transfer inner parts
4WD system does not operate While driving4WD shift switch
TF-131
Clutch pressure switch
Transfer inner parts Symptom Condition Check item Reference page

TF-36
TROUBLE DIAGNOSIS
Revision: October 20052005 QX56
Transfer Control Unit Input/Output Signal Reference ValuesEDS0 02 HJ
TRANSFER CONTROL UNIT INSPECTION TABLE
Specifications with CONSULT-II
Monitored item [Unit] Content Condition Display value
VHCL/S SEN·FR [km/h]
or [mph]Wheel speed (Front
wheel)Vehicle stopped 0 km/h (0 MPH)
Vehicle running
CAUTION:
Check air pressure of tire under standard condition.Approximately
equal to the indi-
cation on speed-
ometer (Inside of
±10%)
VHCL/S SEN·RR [km/h]
or [mph]Wheel speed (Rear
wheel)Vehicle stopped 0 km/h (0 MPH)
Vehicle running
CAUTION:
Check air pressure of tire under standard condition.Approximately
equal to the indi-
cation on speed-
ometer (Inside of
±10%)
ENGINE SPEED [rpm] Engine speedEngine stopped
(Engine speed: Less than 400 rpm)0 rpm
Engine running
(Engine speed: 400 rpm or more)Approximately
equal to the indi-
cation on tachom-
eter
THRTL POS SEN [V]Accelerator pedal posi-
tion (APP) sensor signal
voltageAccelerator pedal: Release Approx. 0.5V
Accelerator pedal: Fully depressed Approx. 4.0V
FLUID TEMP SE [V]Transfer fluid tempera-
ture signal voltageTransfer fluid temperature approx. 20 - 80°C (68 - 176°F) Approx. 1.1 - 0.3V
BATTERY VOLT [V]Power supply voltage for
transfer control unitIgnition switch: ON Battery voltage
2WD SWITCH [ON/OFF]Input condition from
4WD shift switch4WD shift switch: 2WD ON
4WD shift switch: AUTO, 4H or 4LO OFF
AUTO SWITCH [ON/
OFF]Input condition from
4WD shift switch4WD shift switch: AUTO ON
4WD shift switch: 2WD, 4H or 4LO OFF
LOCK SWITCH [ON/
OFF]Input condition from
4WD shift switch4WD shift switch: 4H ON
4WD shift switch: 2WD, AUTO or 4LO OFF
4L SWITCH [ON/OFF]Input condition from
4WD shift switch4WD shift switch: 4LO ON
4WD shift switch: 2WD, AUTO or 4H OFF
N POSI SW TF [ON/
OFF]Condition of neutral-4LO
switch

Vehicle stopped

Engine running

A/T selector lever “N” posi-
tion

Brake pedal depressed4WD shift switch: 2WD,
AUTO or 4HOFF
4WD shift switch: 4H to
4LO (While actuator
motor is operating.)OFF → ON
4WD shift switch: 4LO to
4H (While actuator motor
is operating.)ON → OFF
4WD shift switch: 4LO ON
ATP SWITCH [ON/OFF] Condition of ATP switch

Vehicle stopped

Engine running

A/T selector lever “N”

Brake pedal depressed4WD shift switch
: 4H to 4LO or 4LO to 4H
(While actuator motor is
operating.) ON
Except the above OFF

TF-38
TROUBLE DIAGNOSIS
Revision: October 20052005 QX56
VHCL/S COMP [km/h] or
[mph]Vehicle speedVehicle stopped 0 km/h (0 MPH)
Vehicle running
CAUTION:
Check air pressure of tire under standard condition.Approximately
equal to the indi-
cation on speed-
ometer (Inside of
±10%)
COMP CL TORQ [kgm]Condition of control
torque

Vehicle stopped

Engine running

A/T selector lever “N” posi-
tion

Brake pedal depressed4WD shift switch: 2WD 0 kg-m
4WD shift switch: AUTO39 - 1,353 N·m
(4 - 138 kg-m, 29 -
998 ft-lb)
4WD shift switch: 4H or
4LO1,353 N·m
(138 kg-m, 998 ft-
lb)
DUTY SOLENOID [%]Condition of clutch pres-
sure solenoid

Vehicle stopped

Engine running

A/T selector lever “N” posi-
tion

Brake pedal depressed4WD shift switch: 2WD 4%
4WD shift switch: AUTO 96 - 4%
4WD shift switch: 4H or
4LO4%
2-4WD SOL [ON/OFF]Condition of 2-4WD shift
solenoid valve

Vehicle stopped

Engine running

A/T selector lever “N” posi-
tion

Brake pedal depressed4WD shift switch: 2WD OFF
4WD shift switch: AUTO
ON 4WD shift switch: 4H
4WD shift switch: 4LO
4WD shift switch: AUTO
(“Wait” function is operat-
ing.)OFF
4WD shift switch: 4H
(“Wait” function is operat-
ing.)OFF
2-4WD SOL MON [ON/
OFF]Check signal for transfer
control unit signal output

Vehicle stopped

Engine running

A/T selector lever “N” posi-
tion

Brake pedal depressed4WD shift switch: 2WD OFF
4WD shift switch: AUTO
ON 4WD shift switch: 4H
4WD shift switch: 4LO
4WD shift switch: AUTO
(“Wait” function is operat-
ing.)OFF
4WD shift switch: 4H
(“Wait” function is operat-
ing.)OFF
MOTOR RELAY [ON/
OFF]Condition of transfer
motor relay

Accelerator pedal
depressed

Vehicle stopped

Engine running

Brake pedal depressed4WD 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
selector lever “P” or “N”
position)ON
4WD shift switch: 4H (A/T
selector lever “P” posi-
tion)OFF
("ON" for approx. 2
sec. after shifting
to “P”.)
4WD shift switch: 4H
(Except for A/T selector
lever “P” position)ON Monitored item [Unit] Content Condition Display value

TROUBLE DIAGNOSIS
TF-39
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Revision: October 20052005 QX56
MOTOR RELAY MON
[ON/OFF]Check signal for transfer
control unit signal output

Accelerator pedal
depressed

Vehicle stopped

Engine running

Brake pedal depressed4WD 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
selector lever “P” or “N”
position)ON
4WD shift switch: 4H (A/T
selector lever “P” posi-
tion)OFF
("ON" for approx. 2
sec. after shifting
to “P”.)
4WD shift switch: 4H
(Except for A/T selector
lever “P” position)ON
4WD FAIL LAMP [ON/
OFF]Condition of 4WD warn-
ing lamp4WD warning lamp: ON ON
4WD warning lamp: OFF OFF
2WD IND [ON/OFF]Condition of 4WD shift
indicator lamp (2WD
indicator 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
indicator lamp (AUTO
indicator 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
indicator 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 condition4LO indicator lamp: OFF OFF
4LO indicator lamp: ON ON
AT P I N D [O N / O F F ]Condition of ATP indica-
tor lamp ATP indicator lamp: ON ON
ATP indicator lamp: OFF OFF
SHIFT POS SW1 [ON/
OFF]Condition of actuator
position switch 1
(Low)

Vehicle stopped

Engine running

A/T selector lever “N” posi-
tion

Brake pedal depressed4WD shift switch: 4LO ON
4WD shift switch: 2WD,
AUTO or 4HOFF
SHIFT POS SW2 [ON/
OFF]Condition of actuator
position switch 2
(High)

Vehicle stopped

Engine running

A/T selector lever “N” posi-
tion

Brake pedal depressed4WD shift switch: 4H,
AUTO or 2WDON
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 depressed4WD shift switch: 4H to
4LO (“Wait” function is
operating.)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 depressed4WD shift switch: 4H to
4LO (“Wait” function is
operating.)ON
Except the above OFF Monitored item [Unit] Content Condition Display value

TF-40
TROUBLE DIAGNOSIS
Revision: October 20052005 QX56
Specifications Between Transfer Control Unit Terminals
TRANSFER CONTROL UNIT TERMINAL CONNECTOR LAYOUT
NOTE:
Data are reference value and are measured between each terminal and ground.
SHIFT ACT2 [ON/OFF]Output condition to actu-
ator motor (Low)

Vehicle stopped

Engine running

A/T selector lever “N” posi-
tion

Brake pedal depressed4WD shift switch: 4LO to
4H (“Wait” function is
operating.)ON
Except the above OFF
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 depressed4WD shift switch: 4LO to
4H (“Wait” function is
operating.)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 (Revo-
lution sensor)During drivingApproximately
matches the out-
put shaft speed.
AT GEAR POSI [1/2/3/4/
5]Condition of A/T selec-
tor lever positionDisplays actual A/T gear position. 1/2/3/4/5 Monitored item [Unit] Content Condition Display value
WDIA0204E
Te r m i n a lWire
colorItem Condition Data (Approx.)
1 GR 2-4WD shift solenoid valve

Vehicle stopped

Engine running

A/T selector lever
“N” position

Brake pedal
depressed4WD shift switch: 2WD 0V
4WD shift switch: AUTO, 4H or 4LO Battery voltage
2 B/W4WD 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
depressed4WD shift switch: 4H to 4LO (“Wait” func-
tion is operating.)Battery voltage
Except the above 0V
5 W/B 4WD warning lamp4WD warning lamp: ON 0V
4WD warning lamp: OFF Battery voltage

TROUBLE DIAGNOSIS
TF-45
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Revision: October 20052005 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: October 20052005 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.T F - 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.T F - 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