2004 INFINITI QX56 change time

A/T CONTROL SYSTEM
AT-35
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Shift Change System Diagram
*1: Full phase real-time feedback control monitors movement of gear ratio at gear change, and controls oil
pressure at real-time to achieve the best gear ratio.
Lock-up ControlUCS002CJ
The torque converter clutch piston in the torque converter is engaged to eliminate torque converter slip to
increase power transmission efficiency.
The torque converter clutch control valve operation is controlled by the torque converter clutch solenoid valve,
which is controlled by a signal from TCM, and the torque converter clutch control valve engages or releases
the torque converter clutch piston.
Lock-up Operation Condition Table
TORQUE CONVERTER CLUTCH CONTROL VALVE CONTROL
Lock-up Control System Diagram
Lock-up Released

In the lock-up released state, the torque converter clutch control valve is set into the unlocked state by the
torque converter clutch solenoid and the lock-up apply pressure is drained.
In this way, the torque converter clutch piston is not coupled.
PCIA0013E
Select lever D position 4 position 3 position 2 position
Gear position 5 4 4 3 2
Lock-up×–×××
Slip lock-up××–––
PCIA0014E

TROUBLE DIAGNOSIS
AT-91
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CONSULT-II Function (A/T)UCS002D8
CONSULT-II can display each diagnostic item using the diagnostic test modes shown following.
CONSULT-II REFERENCE VALUE
NOTICE:
1. The CONSULT-II electrically displays shift timing and lock-up timing (that is, operation timing of each sole-
noid).
Check for time difference between actual shift timing and the CONSULT-II display. If the difference is
noticeable, mechanical parts (except solenoids, sensors, etc.) may be malfunctioning. Check mechanical
parts using applicable diagnostic procedures.
2. Shift schedule (which implies gear position) displayed on CONSULT-II and that indicated in Service Man-
ual may differ slightly. This occurs because of the following reasons:
–Actual shift schedule has more or less tolerance or allowance,
–Shift schedule indicated in Service Manual refers to the point where shifts start, and
–Gear position displayed on CONSULT-II indicates the point where shifts are completed.
3. Display of solenoid valves on CONSULT-II changes at the start of shifting, while gear position is displayed
upon completion of shifting (which is computed by TCM).
TCM diagnostic mode Description
WORK SUPPORTSupports inspections and adjustments. Commands are transmitted to the TCM for setting the status
suitable for required operation, input/output signals are received from the TCM and received data is
displayed.
SELF-DIAG RESULTS Displays TCM self-diagnosis results.
DATA MONITOR Displays TCM input/output data in real time.
CAN DIAG SUPPORT MNTR The result of transmit/receive diagnosis of CAN communication can be read.
ACTIVE TEST Operation of electrical loads can be checked by sending drive signal to them.
FUNCTION TESTConducted by CONSULT-II instead of a technician to determine whether each system is “OK” or
“NG”.
ECU PART NUMBER TCM part number can be read.
Item name Condition Display value
AT F T E M P S E 1
0°C (32° F) - 20°C (68°F) - 80°C (176°F)3.2 - 2.5 - 0.8 V
AT F T E M P S E 23.2 - 2.4 - 0.65 V
TCC SOLENOIDWhen perform slip lock-up 0.2 - 0.4 A
When perform lock-up 0.4 - 0.6 A
SLCT LVR POSISelector lever in “N”,“P” position. N/P
Selector lever in “R” position. R
Selector lever in “D” position. D
Selector lever in “4” position. 4
Selector lever in “3” position. 3
Selector lever in “2” position. 2
Selector lever in “1” position. 1
VHCL/S SE·A/T During driving Approximately matches the
speedometer reading.
ENGINE SPEED Engine running Closely matches the tachometer
reading.
LINE PRES SOL During driving 0.2 - 0.6 A
TURBINE REV During driving (lock-up ON) Approximately matches the
engine speed.
VHCL/S SE·MTR During driving Approximately matches the
speedometer reading.

TROUBLE DIAGNOSIS
ATC-57
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Revision: August 20072004 QX56
CHECKING DISCHARGE AIR
1. Press MODE switch four times and then rotate the DEF dial
counterclockwise.
2. Each position indicator should change shape (on display).
3. Confirm that discharge air comes out according to the air distri-
bution table. Refer to AT C - 2 9 , "
Discharge Air Flow" .
Mode door position is checked in the next step.
If NG, go to trouble diagnosis procedure for ATC-63, "
Mode Door
Motor Circuit" .
If OK, continue with next check.
NOTE:
Confirm that the compressor clutch is engaged (sound or visual
inspection) and intake door position is at fresh when the DEF or D/F
is selected.
CHECKING RECIRCULATION
1. Press recirculation ( ) switch one time. Recirculation indica-
tor should illuminate.
2. Press recirculation ( ) switch one more time. Fresh ( )
indicator should illuminate.
3. Listen for intake door position change (blower sound should
change slightly).
If NG, go to trouble diagnosis procedure for AT C - 7 6 , "
Intake Door
Motor Circuit" .
If OK, continue with next check.
NOTE:
Confirm that the compressor clutch is engaged (sound or visual
inspection) and intake door position is at fresh when the DEF or D/F is selected.
CHECKING TEMPERATURE DECREASE
1. Rotate temperature dial counterclockwise (driver or passenger)
until 18°C (60°F) is displayed.
2. Check for cold air at appropriate discharge air outlets.
If NG, listen for sound of air mix door motor operation. If OK, go to
trouble diagnosis procedure for AT C - 11 0 , "
Insufficient Cooling" . If
air mix door motor appears to be malfunctioning, go to AT C - 6 9 ,
"DIAGNOSTIC PROCEDURE FOR AIR MIX DOOR MOTOR
(DRIVER)" or AT C - 7 1 , "DIAGNOSTIC PROCEDURE FOR AIR MIX
DOOR MOTOR (PASSENGER)" .
If OK, continue with next check.
WJIA0406E
WJIA0528E
WJIA0407E
WJIA0408E

ATC-84
TROUBLE DIAGNOSIS
Revision: August 20072004 QX56
SYSTEM DESCRIPTION
Component Parts
Blower speed control system components are:

Front air control

Front blower motor

In-vehicle sensor

Ambient sensor

Optical sensor

Intake sensor
System Operation
Automatic Mode
In the automatic mode, the blower motor speed is calculated by the front air control and variable blower control
based on input from the in-vehicle sensor, optical sensor, intake sensor and ambient sensor, and potentio tem-
perature control (PTC).
When the air flow is increased, the duty ratio of the blower motor′s drive signal is changed at 8%/sec. to pre-
vent a sudden increase in air flow.
In addition to manual air flow control and the usual automatic air flow control, starting air flow control, low
water temperature starting control and high passenger compartment temperature starting control are avail-
able.
Starting Blower Speed Control
Start up from cold soak condition (Automatic mode).
In a cold start up condition where the engine coolant temperature is below 50°C (122°F), the blower will not
operate at blower speed 1 for a short period of time (up to 210 seconds). The exact start delay time varies
depending on the ambient and engine coolant temperatures.
In the most extreme case (very low ambient temperature) the blower starting delay will be 210 seconds as
described above. After the coolant temperature reaches 50°C (122°F), or the 210 seconds has elapsed, the
blower speed will increase to the objective blower speed.
Start up from normal operating or hot soak condition (Automatic mode).
The blower will begin operation momentarily after the AUTO switch is pushed. The blower speed will gradually
rise to the objective speed over a time period of 3 seconds or less (actual time depends on the objective
blower speed).
WJIA0440E

ATC-114
TROUBLE DIAGNOSIS
Revision: August 20072004 QX56
TROUBLE DIAGNOSES FOR UNUSUAL PRESSURE
Whenever system′s high and/or low side pressure(s) is/are unusual, diagnose using a manifold gauge. The
marker above the gauge scale in the following tables indicates the standard (usual) pressure range. Since the
standard (usual) pressure, however, differs from vehicle to vehicle, refer to preceding table (Ambient air tem-
perature-to-operating pressure table).
Both High- and Low-pressure Sides are Too High
High-pressure Side is Too High and Low-pressure Side is Too Low
Gauge indication Refrigerant cycle Probable cause Corrective action
Both high- and low-pressure sides
are too high.Pressure is reduced soon
after water is splashed on
condenser.Excessive refrigerant charge
in refrigeration cycleReduce refrigerant until speci-
fied pressure is obtained.
Air suction by cooling fan is
insufficient.Insufficient condenser cooling
performance
↓
1. Condenser fins are clogged.
2. Improper fan rotation of
cooling fan

Clean condenser.

Check and repair cooling fan
as necessary.

Low-pressure pipe is not
cold.

When compressor is
stopped high-pressure
value quickly drops by
approximately 196 kPa (2
kg/cm
2 , 28 psi). It then
decreases gradually there-
after.Poor heat exchange in con-
denser
(After compressor operation
stops, high-pressure
decreases too slowly.)
↓
Air in refrigeration cycleEvacuate and recharge sys-
tem.
Engine tends to overheat.Engine cooling systems mal-
function.Check and repair engine cool-
ing system.

An area of the low-pres-
sure pipe is colder than
areas near the evaporator
outlet.

Plates are sometimes cov-
ered with frost.

Excessive liquid refrigerant
on low-pressure side

Excessive refrigerant dis-
charge flow

Expansion valve is open a
little compared with the
specification.
↓
Improper expansion valve
adjustmentReplace expansion valve.
AC359A
Gauge indication Refrigerant cycle Probable cause Corrective action
High-pressure side is too high and
low-pressure side is too low.
Upper side of condenser and
high-pressure side are hot,
however, liquid tank is not so
hot.High-pressure tube or parts
located between compressor
and condenser are clogged or
crushed.

Check and repair or replace
malfunctioning parts.

Check lubricant for contami-
nation.
AC360A

TROUBLE DIAGNOSIS
ATC-131
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COMPONENT INSPECTION
In-vehicle Sensor
After disconnecting in-vehicle sensor connector M32, measure resis-
tance between terminals 1 and 4 at sensor component side, using
the table below.
If NG, replace in-vehicle sensor.
Optical Sensor CircuitEJS002CU
COMPONENT DESCRIPTION
The optical sensor is located on the top center of the instrument
panel. It detects sunload entering through windshield by means of a
photo diode. The sensor converts the sunload into a current value
which is then input into the front air control.
OPTICAL INPUT PROCESS
The front air control includes a processing circuit which averages the variations in detected sunload over a
period of time. This prevents adjustments in the ATC system operation due to small or quick variations in
detected sunload.
For example, consider driving along a road bordered by an occasional group of large trees. The sunload
detected by the optical sensor will vary whenever the trees obstruct the sunlight. The processing circuit aver-
ages the detected sunload over a period of time, so that the (insignificant) effect of the trees momentarily
obstructing the sunlight does not cause any change in the ATC system operation. On the other hand, shortly
after entering a long tunnel, the system will recognize the change in sunload, and the system will react accord-
ingly.
Temperature °C (°F) Resistance kΩ
−15 (5) 21.40
−10 (14) 16.15
−5 (23) 12.29
0 (32) 9.41
5 (41) 7.27
10 (50) 5.66
15 (59) 4.45
20 (68) 3.51
25 (77) 2.79
30 (86) 2.24
35 (95) 1.80
40 (104) 1.45
45 (113) 1.18
WJIA0825E
WJIA0569E

AUDIO
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System DescriptionEKS007KA
Refer to Owner's Manual for audio system operating instructions.
Power is supplied at all times

through 15A fuse [No. 17, located in the fuse block (J/B)]

to subwoofer terminal 6

through 20A fuse [No. 31, located in the fuse and fusible link box]

to audio unit terminal 6

to BOSE speaker amp. terminal 1

to AV switch terminal 1 and

to display control unit terminal 1.
With the ignition switch in the ACC or ON position, power is supplied

through 10A fuse [No. 4, located in the fuse block (J/B)]

to audio unit terminal 10 and

to AV switch terminal 2 and

to display control unit terminal 10.
With the ignition switch in the ON or START position, power is supplied

through 10A fuse [No. 12, located in the fuse block (J/B)]

to display control unit terminal 12.
Ground is supplied through the case of the audio unit.
Ground is also supplied

to subwoofer terminal 5

through body grounds B7 and B19 and

to BOSE speaker amp. terminal 17

to AV switch terminal 5 and

to display unit terminal 1 and

to display control unit terminal 3

through body grounds M57, M61 and M79.
Then audio signals are supplied

through audio unit terminals 1, 2, 3, 4, 13, 14, 15 and 16

to BOSE speaker amp. terminals 23, 24, 25, 26, 27, 28, 29 and 30.
Audio signals are amplified by the BOSE speaker amp.
The amplified audio signals are supplied

through BOSE speaker amp. terminals 2, 3, 9,10,11,12, 13, 14, 15, 16, 18 and 19

to terminals + and - of front door speaker LH and RH and

to terminals + and - of front tweeter LH and RH and

to terminals + and - of center speaker and

to terminals + and - of rear door speaker LH and RH and

to terminals + and - of rear door tweeter LH and RH and

to terminals 1 and 2 of subwoofer.
When one of steering wheel audio control switches is pushed, the resistance in steering switch circuit changes
depending on which button is pushed.
REAR AUDIO REMOTE CONTROL UNIT
Power is supplied

from audio unit terminal 32

to rear audio remote control unit terminal 13.
Ground is supplied

to rear audio remote control unit terminal 15

through body grounds B117 and B132.
Audio signals are supplied

NAVIGATION SYSTEM
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NAVIGATION SYSTEMPFP:25915
System DescriptionEKS007LI
The navigation system periodically calculates the vehicle's current
position according to the following three signals: Travel distance of
the vehicle as determined by the vehicle speed sensor, turning angle
of the vehicle as determined by the gyroscope (angular velocity sen-
sor), and the direction of vehicle travel as determined by the GPS
antenna (GPS information).
The current position of the vehicle is then identified by comparing the
calculated vehicle position with map data read from the map DVD-
ROM, which is stored in the DVD-ROM drive (map-matching), and
indicated on the screen with a current-location mark.
By comparing the vehicle position detection results found by the
GPS and by map-matching, more accurate vehicle position data can
be used.
The current vehicle position will be calculated by detecting the dis-
tance the vehicle moved from the previous calculation point and its
direction.
TRAVEL DISTANCE
Travel distance calculations are based on the vehicle speed sensor input signal. Therefore, the calculation
may become incorrect as the tires wear down. To prevent this, an automatic distance fine adjustment function
has been adopted. Adjustments can be made in extreme cases (such as driving with tire chain fitted on tires).
Refer to AV-107, "
Confirmation/Adjustment Mode" .
TRAVEL DIRECTION
Change in the travel direction of the vehicle is calculated by a gyroscope (angular velocity sensor) and a GPS
antenna (GPS information). As the gyroscope and GPS antenna have both merit and demerit, input signals
from them are prioritized in each situation. However, this order of priority may change in accordance with more
detailed travel conditions so that the travel direction is detected more accurately.
MAP-MATCHING
Map-matching is a function that repositions the vehicle on the road
map when a new location is judged to be the most accurate. This is
done by comparing the current vehicle position, calculated by the
method described in the position detection principle, with the road
map data around the vehicle, read from the map DVD-ROM stored in
the DVD-ROM drive.
Therefore, the vehicle position may not be corrected after the vehicle
is driven over a certain distance or time in which GPS information is
hard to receive. In this case, the current-location mark on the display
must be corrected manually.
CAUTION:
The road map data is based on data stored in the map DVD-
ROM.
WKIA1371E
SEL684V
Type Advantage Disadvantage
Gyroscope (angular velocity sensor)

Can detect the vehicle's turning angle
quite accurately.
Direction errors may accumulate when the
vehicle is driven for long distances without
stopping.
GPS antenna (GPS information)

Can detect the vehicle's travel direction
(North/South/East/West).
Correct direction cannot be detected when
the vehicle speed is low.
SEL685V