2004 INFINITI QX56 engine

TROUBLE DIAGNOSIS
ATC-37
C
D
E
F
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K
L
MA
B
AT C
Revision: August 20072004 QX56
Component Parts and Harness Connector LocationEJS002C6
ENGINE COMPARTMENT
WJIA0833E

ATC-54
TROUBLE DIAGNOSIS
Revision: August 20072004 QX56
Using Confirmation/Adjustment Mode (NAVI)
NOTE:
Ambient temperature must be at least 10° C (50° F) to run self-diagnosis.
1. Start engine.
2. Turn the audio system off.
3. While pressing the "PAUSE/MUTE" button, turn the volume con-
trol dial clockwise or counterclockwise for 30 clicks or more.
(When the self diagnosis mode is started, a short beep will be
heard.)

Shifting from current screen to previous screen is performed
by pressing "PREV" button.
4. The initial self-diagnosis screen will be shown, and items "Self-
Diagnosis (DCU)", "Self-Diagnosis (NAVI)", "Confirmation/
Adjustment" and "CAN DIAG SUPPORT MONITOR" will
become selective.
5. When "Confirmation/Adjustment" is selected on the initial self-
diagnosis screen, the operation will enter CONFIRMATION/
ADJUSTMENT mode. In this mode, check and adjustment of
each item will become possible.
6. The initial trouble diagnosis screen will be shown, and items
"display Diagnosis", "Vehicle Signals", "Auto Climate Control"
and "Navigation" will become selective.
7. Select the "Auto Climate Control" switch on "CONFIRMATION/
ADJUSTMENT" screen to display the "Auto Climate Control"
diagnosis screen to begin diagnosis The front blower speed indi-
cation bars will flash and the ambient temperature display will
indicate 0° during the self-diagnosis. Fault codes (if any are
present) will be displayed in the ambient temperature display area. Refer to ATC-55, "
SELF-DIAGNOSIS
CODE CHART" .
WKIA1504E
SKIA4207E
SKIA4220E

ATC-56
TROUBLE DIAGNOSIS
Revision: August 20072004 QX56
Operational Check (Front)EJS002CB
The purpose of the operational check is to confirm that the system operates properly.
CHECKING MEMORY FUNCTION
1. Set the temperature to 90°F or 32°C.
2. Press OFF switch [hold fan (down) switch down until system
shuts OFF].
3. Turn ignition switch OFF.
4. Turn ignition switch ON.
5. Press the AUTO switch.
6. Confirm that the set temperature remains at previous tempera-
ture.
7. Press OFF switch [hold fan (down) switch down until system
shuts OFF].
If NG, go to trouble diagnosis procedure for ATC-121, "
Memory
Function" .
If OK, continue with next check.
CHECKING BLOWER
1. Press fan (up) switch. Blower should operate on low speed. The
front blower speed symbol should have one bar lit (on display).
2. Press fan (up) switch again, and continue checking blower
speed and blower symbol until all speeds are checked.
3. Leave blower on maximum speed.
If NG, go to trouble diagnosis procedure for AT C - 8 5 , "
DIAGNOSTIC
PROCEDURE FOR BLOWER MOTOR" .
If OK, continue with next check.Conditions : Engine running and at normal operating temperature
WJIA0404E
WJIA0411E
WJIA0404E
WJIA0405E

TROUBLE DIAGNOSIS
ATC-59
C
D
E
F
G
H
I
K
L
MA
B
AT C
Revision: August 20072004 QX56
Operational Check (Rear)EJS002CC
The purpose of the operational check is to confirm that the system operates properly.
CHECKING BLOWER
1. Turn the rear fan switch (front) clockwise to "1". The rear blower
should operate on low speed.
2. Turn the rear fan switch (front) clockwise again to switch position
"2", "3", and "4" until all speeds are checked.
3. Leave blower on maximum speed.
If NG, go to trouble diagnosis procedure for AT C - 9 0 , "
Rear Blower
Motor Circuit" .
If OK, continue with next check.
CHECKING TEMPERATURE DECREASE
1. Rotate rear temperature/mode dial (front) fully counterclockwise.
2. Check for cold air at appropriate discharge air outlets (headliner
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 - 7 3 ,
"DIAGNOSTIC PROCEDURE FOR AIR MIX DOOR MOTOR
(REAR)" .
If OK, continue with next check.
CHECKING TEMPERATURE INCREASE
1. Rotate rear temperature/mode dial (front) clockwise.
2. Check for hot air at appropriate discharge air outlets (floor out-
lets).
If NG, listen for sound of air mix door motor operation. If OK, go to
trouble diagnosis procedure for AT C - 11 7 , "
Insufficient Heating" . If
air mix door motor appears to be malfunctioning, go to AT C - 7 3 ,
"DIAGNOSTIC PROCEDURE FOR AIR MIX DOOR MOTOR
(REAR)" .
If OK, continue with next check.Conditions : Engine running and at normal operating temperature
WJIA0838E
WJIA0626E
WJIA0627E

TROUBLE DIAGNOSIS
ATC-83
C
D
E
F
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H
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K
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MA
B
AT C
Revision: August 20072004 QX56
Front Blower Motor CircuitEJS002CI
SYMPTOM:

Blower motor operation is malfunctioning.
INSPECTION FLOW
*1 .AT C - 5 6 , "Operational Check
(Front)"
*2AT C - 5 3 , "A/C System Self-diagnosis
Function"
*3AT C - 5 5 , "SELF-DIAGNOSIS CODE
CHART"
*4ATC-85, "DIAGNOSTIC PROCE-
DURE FOR BLOWER MOTOR"
*5EC-410, "DTC P1217 ENGINE
OVER TEMPERATURE"
WJIA0771E

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-108
TROUBLE DIAGNOSIS
Revision: August 20072004 QX56
8. CHECK REFRIGERANT PRESSURE SENSOR
WITH CONSULT-II
1. Start engine.
2. Check voltage of refrigerant pressure sensor. Refer to AT C - 3 3 , "
CONSULT-II Function (BCM)" .
WITHOUT CONSULT-II
1. Start engine.
2. Check voltage between ECM harness connector F54 terminal
70 (B/W) and ground.
OK or NG
OK >>
WITH CONSULT-II
GO TO 9.

WITHOUT CONSULT-II
GO TO 10.
NG >> Refer to EC-607, "
REFRIGERANT PRESSURE SENSOR" .
9. CHECK BCM INPUT (FAN ON) SIGNAL
Check FAN ON/OFF signal while changing the front switch position.
Refer to ATC-33, "
CONSULT-II Function (BCM)" .
OK or NG
OK >> GO TO 12.
NG >> GO TO 10.
10. CHECK CIRCUIT CONTINUITY BETWEEN BCM AND FRONT AIR CONTROL
1. Turn ignition switch OFF.
2. Disconnect BCM connector M18 and front air control connector
M49.
3. Check continuity between BCM harness connector M18 terminal
28 (L/R) and front air control harness connector M49 terminal 10
(L/R).
OK or NG
OK >> GO TO 11.
NG >> Repair harness or connector.
Te r m i n a l s
Condition Voltage (+)
(-)
ECM con-
nectorTe r m i n a l N o .
(Wire color)
F54 70 (B/W) Ground A/C switch: ON Approx. 0.36 - 3.88V
LJIA0124E
FRONT FAN SWITCH ON : FAN ON SIG ON
FRONT FAN SWITCH OFF : FAN ON SIG OFF
WJIA0469E
28 - 10 Continuity should exist.
WJIA0450E

TROUBLE DIAGNOSIS
ATC-113
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AT C
Revision: August 20072004 QX56
PERFORMANCE CHART
Test Condition
Testing must be performed as follows:
Te s t R e a d i n g
Recirculating-to-discharge Air Temperature Table
Ambient Air Temperature-to-operating Pressure Table
Vehicle location Indoors or in the shade (in a well-ventilated place)
Doors Closed
Door window Open
Hood Open
TEMP. Max. COLD
Mode switch
(Ventilation) set
Recirculation (REC) switch
(Recirculation) set
Fan (blower) speedMax. speed set
Engine speed Idle speed
Operate the air conditioning system for 10 minutes before taking measurements.
Inside air (Recirculating air) at blower assembly inlet
Discharge air temperature at center ventilator
°C (°F) Relative humidity
%Air temperature
°C (°F)
50 - 6020 (68) 5.3 - 6.5 (42 - 44)
25 (77) 9.7 - 11.5 (49 - 53)
30 (86) 13.8 - 16.3 (57 - 61)
35 (95) 18.0 - 21.2 (64 - 70)
40 (104) 22.2 - 25.7 (72 - 78)
60 - 7020 (68) 6.5 - 7.7 (44 - 46)
25 (77) 11.5 - 13.3 (53 - 56)
30 (86) 16.3 - 18.8 (61 - 66)
35 (95) 21.2 - 24.0 (70 - 75)
40 (104) 25.7 - 29.2 (78 - 85)
Ambient air
High-pressure (Discharge side)
kPa (kg/cm
2 , psi)Low-pressure (Suction side)
kPa (kg/cm2 , psi) Relative humidity
%Air temperature
°C (°F)
50 - 7020 (68)680 - 840
(6.94 - 8.57, 98.6 - 121.8)160 - 198
(1.63 - 2.02, 23.2 - 28.7)
25 (77)800 - 985
(8.16 - 10.05, 116.0 - 142.8)198 - 245
(2.02 - 2.50, 28.7 - 35.5)
30 (86)940 - 1,150
(9.59 - 11.73, 136.3 - 166.8)225 - 278
(2.30 - 2.84, 32.6 - 40.3)
35 (95)1,160 - 1,410
(11.83 - 14.38, 168.2 - 204.5)273 - 335
(2.78 - 3.42, 39.6 - 48.6)
40 (104)1,325 - 1,620
(13.52 - 16.52, 192.1 - 234.9)325 - 398
(3.32 - 4.06, 47.1 - 57.7)