INFINITI QX56 2004 Factory Service Manual

TF-36
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTION
Revision: August 20072004 QX56
N position switch TF [ON-OFF] N position switch of transfer
Line pressure switch [ON-OFF] Line pressure switch
Clutch pressure switch [ON-OFF] Clutch pressure switch
ATP switch [ON-OFF]—
N position switch AT [ON-OFF] “N” position on A/T PNP switch
R position switch AT [ON-OFF] “R” position on A/T PNP switch
P position switch AT [ON-OFF] “P” position on A/T PNP switch
ABS operation switch [ON-OFF] ABS operation switch
Wait detection switch [ON-OFF] —
Throttle positionThrottle opening recognized by transfer
control unit
4WD-mode4WD-mode recognized by transfer control
unit (2WD, AUTO, 4H & 4LO)
Vehicle speed comp [km/h (MPH)]Vehicle speed recognized by transfer con-
trol unit
*Control torque [N·m (kg-m, ft.-lb.)]Calculated torque recognized by transfer
control unit
Duty solenoid valve [%]
(Transfer 4WD solenoid valve)—
2-4WD shift solenoid valve [ON-
OFF]
Control signal outputs of transfer control
unit Transfer motor relay [ON-OFF]
Shift activating 1 [ON-OFF]
Shift activating 2 [ON-OFF]
2-4WD shift solenoid valve monitor
[ON-OFF]
Check signal (re-input signal) of transfer
control unit control signal output is dis-
played. If circuit is shorted or open, ON/OFF
state does not change. Transfer motor relay monitor [ON-
OFF]
Shift activating monitor 1 [ON-OFF]
Shift activating monitor 2 [ON-OFF]
4WD fail lamp [ON-OFF]Transfer control unit control signal output for
4WD warning lamp (left)
Shift position switch 1 [ON-OFF] —
Shift position switch 2 [ON-OFF] —
2WD indicator lamp [ON-OFF]Transfer control unit control signal output for
4WD shift indicator lamp (rear)
AUTO indicator lamp [ON-OFF]Transfer control unit control signal output for
4WD shift indicator lamp (front & rear)
LOCK indicator lamp [ON-OFF]Transfer control unit control signal output for
4WD shift indicator lamp (center)
4LO indicator lamp [ON-OFF]Transfer control unit control signal output for
4WD shift indicator lamp (right) Item [Unit]Monitor item
Remarks ECU
INPUT
SIGNALSMAIN
SIGNALSSELEC-
TION
FROM
MENU

ON BOARD DIAGNOSTIC SYSTEM DESCRIPTION
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*: This item is indicated as “COMP CL TORQ”.Clutch limit [N·m (kg-m, ft.-lb.)]Clutch force release limit value set in
WORK SUPPORT
Voltage [V]Value measured by voltage probe is dis-
played.
Frequency [Hz]Value measured by pulse probe is dis-
played. If measurement is impossible, “#”
sign is displayed. “#” sign is also displayed
at the final data value until the measure-
ment result is obtained.
DUTY-HI
Duty cycle value for measurement probe is
displayed.
DUTY-LOW
PLS WIDTH-HI
Measured pulse width of measurement
probe is displayed.
PLS WIDTH-LOW
FR/RR G-SEN [G] Displayed, but do not use.
TF F SPEED [km/h], [MPH] Displayed, but do not use.
AT R SPEED [km/h], [MPH] Indicates A/T rear vehicle speed.
A/T actual gear position Indicates A/T actual gear position.
VDC OPER SW [ON-OFF] Indicates VDC operation switch.
TCS OPER SW [ON-OFF] Indicates TCS operation switch.
AT P L A M P [O N - O F F ]Indicates C/U control signal output of ATP
lamp. Item [Unit]Monitor item
Remarks ECU
INPUT
SIGNALSMAIN
SIGNALSSELEC-
TION
FROM
MENU

TF-38
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTION
Revision: August 20072004 QX56
REFERENCE VALUE IN DATA MONITOR MODE
Indicated items
(Screen terms for CONSULT-II, “DATA
MONITOR” mode)Display Conditions
Throttle position sensor
(THRTL POS SEN) 0.0/8 - 8.0/8 Throttle valve fully closed to fully open
Transfer fluid temperature sensor
(FLUID TEMP SE)Approx. 1.5 - 0.5V Transfer fluid temperature approx. 20 - 80°C (68 - 176°F)
ABS operation switch
(ABS OPER SW)OFF ABS is not operating.
ON ABS is operating.
2WD position
(2WD SWITCH)ON 4WD shift switch is in “2WD”.
OFF Except the above condition
Lock position
(LOCK SWITCH)ON 4WD shift switch is in “4H”.
OFF Except the above condition
Neutral-4LO switch
(N POSI SW TF)
AT P s w i tc h
(ATP SWITCH)
Wait detection switch
(WAIT DETCT SW)4WD shift switch position2WD,
AUTO, 4H(N) 4LO
AT P s w i t c h O F F O N O F F
Neutral-4LO switch/Wait detec-
tion switch See Note.OFF ON
Note: When shifting into or out of “4LO” the switches turn ON when “Wait” function is oper-
ating and they turn OFF when “Wait” function is canceled.
Tran s fe r mo to r re lay
(MOTOR RELAY)
Transfer motor relay monitor
(MOTOR RELAY MON)Throttle valve4WD
shift
switchA/T selector
leverMotor relay/
Motor relay
monRemarks
Fully closed2WD — OFF —
AUTO,
4LOP, N O F F
ON for approx. 2 sec. after
shifting to “P” and “N”
Others ON
4HPOFF
ON for approx. 2 sec. after
shifting to “P”
Others ON
Line pressure switch
(LINE PRES SW)OFFThe vehicle has been left at room temperature for 5 min-
utes and more with ignition switch in “OFF” position.
ONIgnition switch in “ON”, and 4WD shift switch in “AUTO” or
“4H” and A/T selector lever in “D”.
Clutch pressure switch
(CL PRES SW)OFFIgnition switch in “ON”, and 4WD shift switch in “2WD”.
(“Wait” function is not operating.)
ONIgnition switch in “ON”, and 4WD shift switch in “AUTO” or
“4H” and A/T selector lever in “D”. (“Wait” function is not
operating.)
Vehicle speed
(VHCL/S COMP)0 km/h (0 MPH) — —
Control torque
(COMP CL TORQ)0 kg-m
4WD shift switch
(“Wait” function is not oper-
ating.)In “2WD” position
39 - 1,353 N·m
(4 - 138 kg-m, 29 - 998 ft.-lb.)In “AUTO” position
1,353 N·m
(138 kg-m, 998 ft.-lb.)In “4H” or “4LO” position
4WD solenoid
(DUTY SOLENOID)4% In “2WD” position
96 - 4% In “AUTO” position
4% In “4H” or “4LO” position

ON BOARD DIAGNOSTIC SYSTEM DESCRIPTION
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2-4WD shift solenoid valve
(2-4WD SOL)
2-4WD shift solenoid monitor
(2-4WD SOL MON)OFF
4WD shift switchIn “2WD” position
ON (“Wait” function is not oper-
ating.)
In “AUTO” position
OFF (“Wait” function is operat-
ing.)
ON (“Wait” function is not oper-
ating.)
In “4H” position
OFF (“Wait” function is operat-
ing.)
ON In “4LO” position
Battery voltage
(BATTERY VOLT)Approx. 12V Key switch “ON” and engine at rest
Approx. 13 - 14V During idling
AUTO switchOFF 4WD shift switch in other than “AUTO” position
ON 4WD shift switch in “AUTO” position
4L switchOFF 4WD shift switch in other than “4LO” position
ON 4WD shift switch in “4LO” position
N position switch
(N POSI SW AT)OFF A/T selector lever in other than “N” position
ON A/T selector lever in “N” position
R position switch
(R POSI SW AT)OFF A/T selector lever in other than “R” position
ON A/T selector lever in “R” position
P position switch
(P POSI SW AT)OFF A/T selector lever in other than “P” position
ON A/T selector lever in “P” position
Throttle opening
(THROTTLE POSI)0.0/8 - 8.0/8 Throttle fully closed (0.0/8) or throttle fully open (8.0/8) Indicated items
(Screen terms for CONSULT-II, “DATA
MONITOR” mode)Display Conditions

TF-40
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTION
Revision: August 20072004 QX56
4WD-mode2WD
4WD shift
switchIn “2WD” position
AUTO In “AUTO” position
LOCK In “4H” position
4L In “4LO” position
Front wheel speed
(VHCL/S SEN-FR)0 - 255 km/h (0 - 158 MPH) 0 km/h (vehicle at standstill)
Rear wheel speed
(VHCL/S SEN-RR)0 - 255 km/h (0 - 158 MPH) 0 km/h (vehicle at standstill)
Shift ACTR operating 1
(SHIFT ACT 1)
Shift activating monitor 1
(SHIFT AC MON 1)OFF During normal operation
ON During shifts from “4H” to “4LO” position
Shift ACTR operating 2
(SHIFT ACT 2)
Shift activating monitor 2
(SHIFT AC MON 2)OFF During normal operation
ON During shifts from “4LO” to “4H” position
4WD fail lampOFF During normal operation
ONDuring 2-second period (after key switch turned to “ON”)
or when system is out of order
Shift ACTR position sensing switch 1
(SHIFT POS SW 1)OFF 4WD shift switch is in a position other than “4LO”.
ON 4WD shift switch in “4LO” position
Shift ACTR position sensing switch 2
(SHIFT POS SW 2)OFF 4WD shift switch in “4LO” position
ON 4WD shift switch is in a position other than “4LO”.
2WD indicator lamp
(2WD IND)OFF Engine at rest or system out of order
ON Except the above condition Indicated items
(Screen terms for CONSULT-II, “DATA
MONITOR” mode)Display Conditions

ON BOARD DIAGNOSTIC SYSTEM DESCRIPTION
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Revision: August 20072004 QX56
WORK SUPPORT
Purpose
When there is no problem with transfer and 4WD system, the following symptom in “AUTO” mode may be
claimed by a customer.

Vibration when accelerating on snow-covered or icy roads. (Note)
AUTO indicator lamp
(AUTO IND)OFFEngine at rest during 2WD-mode operation or system out
of order
ON 4WD shift switch in “4LO” or “4H” or “AUTO” position
LOCK indicator lamp
(LOCK IND)OFFEngine at rest and 4WD shift switch in “AUTO” position
during 2WD-mode operation or system out of order
ON 4WD shift switch in “4H” or “4LO” position
4LO indicator lamp
(4L IND)OFFEngine at rest and 4WD shift switch in “AUTO” position
during 2WD-mode operation or system out of order
ON 4WD shift switch in “4LO” position
Clutch force release limit
(CL/F RLS LIM)0.2, 0.3, 1.2 kgmIndicates the clutch force release setting applied using the
scan tool. 0.3 kgm is the default setting.
VDC operation switch
(VDC OPER SW)OFF VDC is not operating.
ON VDC is operating.
TCS operation switch
(TCS OPER SW)OFF TCS is not operating.
ON TCS is operating.
ATP indicator lamp
(ATP IND)OFF Normal operation.
ONDriver is attempting to shift into or out of 4L while the AT is
not in neutral.
Transfer case F speed
(T/F F SPEED)0.0 km/h (0.0 MPH) —
Automatic transmission R speed
(AT R SPEED)0.0 km/h (0.0 MPH) —
Automatic transmission gear position
(AT GEAR POSI)1,2,3,4 Displays actual AT gear position. Indicated items
(Screen terms for CONSULT-II, “DATA
MONITOR” mode)Display Conditions

TF-42
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTION
Revision: August 20072004 QX56
It is possible to deal with these symptoms by changing “CLUTCH FORCE RELEASE LIMIT VALUE”.
However, be careful when changing the values because it may adversely affect driving performance.
NOTE:
A slight shock is felt at a few hertz as if it were being pushed lightly from behind.
CONSULT-II Setting Procedure
1. Turn ignition switch to “OFF” position.
CAUTION:
If CONSULT-II is used with no connection of CONSULT-II CON-
VERTER, malfunctions might be detected in self-diagnosis
depending on control unit which carry out CAN communication.
2. Connect CONSULT-II and CONSULT-II CONVERTER to data
link connector.
3. Turn ignition switch to “ON” position.
4. Touch “START (NISSAN BASED VHCL)”.
5. Touch “ALL MODE AWD/4WD”.
If "ALL MODE AWD/4WD" is not indicated, refer to GI-39,
"CONSULT-II Data Link Connector (DLC) Circuit" .
6. Touch “WORK SUPPORT”.
7. Select WORK ITEM by touching “CLUTCH/F RLS LIM ADJ”.
CLUTCH FORCE RELEASE LIMIT ADJUSTMENT
1.2 kg-m: Tight corner braking symptom is alleviated. 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.
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.
BCIA0029E
BCIA0031E
WDIA0085E
SMT968D

ON BOARD DIAGNOSTIC SYSTEM DESCRIPTION
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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.
SMT969D
SMT970D

TF-44
TROUBLE DIAGNOSIS — INTRODUCTION
Revision: August 20072004 QX56
TROUBLE DIAGNOSIS — INTRODUCTIONPFP:00000
IntroductionEDS0017W
DESCRIPTION
When a malfunction (indicated by the 4WD warning lamp illumination) occurs, collect information first from the
customer about how the malfunction occurs. Then, proceed with the diagnosis presuming it is the cause. Also
inspect the electrical system, paying close attention to other possibilities such as fluid level and leaks.
All-mode 4WD transfer is controlled by transfer control unit and sensors.
If a malfunction occurs in the all-mode 4WD system, the 4WD warning lamp lights up to inform of the system
malfunction. There are two ways to identify the cause of the malfunction.
1. Performing the self-diagnosis. (The 4WD warning lamp will indicate what kind of malfunction has occurred
by flickering.)
2. Performing diagnosis using CONSULT-II.
DIAGNOSTIC WORKSHEET
Information from Customer
KEY POINTS

WHAT ..... Vehicle model

WHEN..... Date, Frequencies

WHERE..... Road conditions

HOW..... Operating conditions, Symptoms
Diagnostic Worksheet
Information sheet from customer
Customer name MR/MS Model & Year VIN
Transfer model
AT X 1 4 BEngine Mileage
Incident Date Manuf. Date In Service Date
Frequency❏ Continuous ❏ Intermittent ( times a day)
Symptoms❏ 4WD shift indicator lamp does not turn on.
❏ 4WD warning lamp does not turn on.
❏ 4WD shift indicator lamp does not turn off.
❏ ATP warning lamp does not turn on.
❏ 4LO indicator lamp does not turn on.
❏ 4WD shift indicator lamp does not indicate “4H”.
❏ 4WD shift indicator lamp repeats flicking.
❏ Tight corner braking symptom occurs.
❏ 4WD system does not operate.
❏ Others.
4WD warning lamp❏ Continuously lit❏ Not lit
1.❏ Listen to customer complaints.TF-47
2.❏ Check transfer fluid.TF-47
❏ Leakage
❏ Fluid condition
❏ Fluid level
3.❏ Road testingTF-47
❏ 1. Check before engine is started.
❏ 2. Check at idle.
❏ 3. Cruise test
4.❏ Perform self-diagnosis NG items (with CONSULT-II and without CONSULT-II).TF-31
, TF-28

TROUBLE DIAGNOSIS — INTRODUCTION
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5.❏ Check component. Repair or replace the damaged parts.TF-109
6.❏ Perform final check. Perform road test (1 through 3).TF-47