Air INFINITI QX56 2004 Factory Service Manual

TROUBLE DIAGNOSIS
ATC-35
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AT C
Revision: August 20072004 QX56
How to Perform Trouble Diagnosis for Quick and Accurate RepairEJS002C5
WORK FLOW
SYMPTOM TABLE
*1ATC-56, "Operational Check (Front)"
or AT C - 5 9 , "
Operational Check
(Rear)" .
SHA9 00 E
Symptom Reference Page
A/C system does not come on. Go to Trouble Diagnosis Procedure for A/C System.AT C - 6 0 , "
Power
Supply and
Ground Circuit for
Front Air Control"
A/C system display is malfunctioning. Go to "Navigation System".AV-61, "NAVIGA-
TION SYSTEM"
A/C system cannot be controlled. Go to Self-diagnosis Function.AT C - 5 3 , "
A/C Sys-
tem Self-diagno-
sis Function"
Air outlet does not change.
Go to Trouble Diagnosis Procedure for Mode Door Motor.AT C - 6 3 , "Mode
Door Motor Cir-
cuit"Mode door motor is malfunctioning.
Discharge air temperature does not change.
Go to Trouble Diagnosis Procedure for Air Mix Door Motor.ATC-67, "
Air Mix
Door Motor Cir-
cuit"Air mix door motor is malfunctioning.
Intake door does not change.
Go to Trouble Diagnosis Procedure for Intake Door Motor.ATC-76, "
Intake
Door Motor Cir-
cuit"Intake door motor is malfunctioning.
Defroster door motor is malfunctioning. Go to Trouble Diagnosis Procedure for Defroster Door Motor.AT C - 7 9 ,
"Defroster Door
Motor Circuit"
Front blower motor operation is malfunction-
ing.Go to Trouble Diagnosis Procedure for Front Blower Motor.AT C - 8 3 , "Front
Blower Motor Cir-
cuit"
Rear blower motor operation is malfunction-
ing.Go to Trouble Diagnosis Procedure for Rear Blower Motor.AT C - 9 0 , "Rear
Blower Motor Cir-
cuit"
Rear discharge air temperature and/or air
outlet does not change.Go to Trouble Diagnosis Procedure for Rear Air Control circuit.ATC-101, "Rear
Air Control Circuit"
Magnet clutch does not engage. Go to Trouble Diagnosis Procedure for Magnet Clutch.ATC-104, "Mag-
net Clutch Circuit"
Insufficient cooling Go to Trouble Diagnosis Procedure for Insufficient Cooling.AT C - 11 0 , "Insuffi-
cient Cooling"
Insufficient heating Go to Trouble Diagnosis Procedure for Insufficient Heating.AT C - 11 7 , "Insuffi-
cient Heating"
Noise Go to Trouble Diagnosis Procedure for Noise.ATC-118, "Noise"

TROUBLE DIAGNOSIS
ATC-51
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Revision: August 20072004 QX56
Front Air Control Terminals and Reference ValueEJS002C9
Measure voltage between each terminal and ground by following
Terminals and Reference Value for Front Air Control.
PIN CONNECTOR TERMINAL LAYOUT
TERMINALS AND REFERENCE VALUE FOR FRONT AIR CONTROL
WJIA0759E
WJIA0402E
Te r m i -
nal No.Wire
colorItemIgnition
switchConditionVoltage (V)
(Approx.)
1 B Ground - - 0V
2YPower supply for each door motor
PBRON - 0 - 5V
3 W/G Air mix door motor (Driver) CW ON Clockwise rotation Battery voltage
4 G Air mix door motor (Driver) CCW ON Counterclockwise rotation Battery voltage
5 BR/W Mode door motor CW ON Clockwise rotation Battery voltage
6 P/L Mode door motor CCW ON Counterclockwise rotation Battery voltage
7 O Intake door motor CCW ON Counterclockwise rotation Battery voltage
8 G/B Intake door motor CW ON Clockwise rotation Battery voltage
9 L/B Intake sensor ON - 0 - 5V
10 L/R Fan ON signal ONFan switch OFF 5V
Fan switch ON 0V
11 Y/B Rear defroster request ON - Battery voltage
12 W/R Compressor ON signal ONA/C switch OFF 5V
A/C switch ON 0V
13 G/R Variable blower control ON - 0 - 5V
14 Y/G Power supply for IGN ON - Battery voltage
15 P Ground for each door motor PBR ON - 0 - 5V
16 GR Mode door motor PBR feedback ON - 0 - 5V
17 P Ambient sensor ON - 0 - 5V
18 SBAir mix door motor (Driver) PBR
feedbackON - 0 - 5V
19 LG Defroster door motor CW ON Clockwise rotation Battery voltage
20 P/B Defroster door motor CCW ON Counterclockwise rotation Battery voltage

ATC-52
TROUBLE DIAGNOSIS
Revision: August 20072004 QX56
21 V/R Sensor ground ON - 0 - 5V
22 Y/R Power supply for BAT - - Battery voltage
23 R/L Power supply for illumination ON Park lamps ON Battery voltage
24 BR Illumination ground - Park lamps ON
25 LG/B Defroster door motor feedback ON - 0 - 5V
26 R/B Front blower motor request ONFront blower motor OFF Battery voltage
Front blower motor ON 0V
27 GR/R Air mix door motor (Rear) CW ON Clockwise rotation Battery voltage
28 L/Y Air mix door motor (Rear) CCW ON Counterclockwise rotation Battery voltage
29 W/G Water valve ONWater valve open 0V
Water valve closed 5V
31 W/V Optical sensor (Passenger) ON - 0 - 5V
32 LG/R In-vehicle sensor signal ON - 0 - 5V
33 V Air mix door motor (Rear) set point ON - 0 - 5V
34 W CAN-H ON - -
35 R CAN-L ON - -
36 G/W Air mix door motor (Passenger) CW ON Clockwise rotation Battery voltage
37 LAir mix door motor (Passenger)
CCWON Counter clockwise rotation Battery voltage
38 W/L Rear blower motor request ONRear blower motor OFF Battery voltage
Rear blower motor ON 0V
39 Y/B Rear select signal ON - 0 - 5V
40 G/O Optical sensor (Driver) ON - 0 - 5V
41 R/WAir mix door motor (Passenger) PBR
feedbackON - 0 - 5V
42 R/YAir mix door motor (Rear) PBR feed-
backON - 0 - 5V
43 BR/Y In-vehicle sensor motor (power) ON - Battery voltage
44 O/B In-vehicle sensor motor (ground) ON - 0V Te r m i -
nal No.Wire
colorItemIgnition
switchConditionVoltage (V)
(Approx.)
PIIA2344E

TROUBLE DIAGNOSIS
ATC-53
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Revision: August 20072004 QX56
A/C System Self-diagnosis FunctionEJS002CA
DESCRIPTION
Using Front Air Control Switches
NOTE:
Ambient temperature must be at least 10° C (50° F) to run self-diagnosis.
The self-diagnostic system diagnoses sensors, door motors, blower motor, etc. Refer to applicable sections
(items) for details. Shifting from usual control to the self-diagnostic system is accomplished by turning the igni-
tion switch ON and pressing the fan (down) switch while turning the passenger temperature dial in either direc-
tion (hold momentarily). Within 3 seconds of doing this, press the AUTO switch. The front blower speed
indication 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 AT C - 5 5 , "
SELF-
DIAGNOSIS CODE CHART" .
WJIA0837E

TROUBLE DIAGNOSIS
ATC-55
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Revision: August 20072004 QX56
SELF-DIAGNOSIS CODE CHART
Code No. Reference page
02 EE changed by calibrationATC-135, "
FRONT AIR CONTROL"
03 Battery voltage out of rangeSC-4, "BATTERY"
04 Mode switch circuit open or shortATC-135, "FRONT AIR CONTROL"
05 Blower motor malfunctionAT C - 8 3 , "Front Blower Motor Circuit"
12 Air mix door motor (Passenger) circuit malfunctionAT C - 7 1 , "DIAGNOSTIC PROCEDURE FOR AIR MIX DOOR
MOTOR (PASSENGER)"
20 BCM not responding to A/C requestATC-104, "Magnet Clutch Circuit"
21 BCM not responding to rear defroster requestGW-78, "REAR WINDOW DEFOGGER"
22 Air mix door motor (Driver) circuit malfunctionAT C - 6 9 , "DIAGNOSTIC PROCEDURE FOR AIR MIX DOOR
MOTOR (DRIVER)"
30 In-vehicle sensor circuit out of range (low)
ATC-128, "In-vehicle Sensor Circuit"31 In-vehicle sensor circuit out of range (high)
34 Air mix door motor (Driver) PBR circuit malfunctionAT C - 6 9 , "
DIAGNOSTIC PROCEDURE FOR AIR MIX DOOR
MOTOR (DRIVER)"
36Air mix door motor (Passenger) PBR circuit malfunc-
tionAT C - 7 1 , "DIAGNOSTIC PROCEDURE FOR AIR MIX DOOR
MOTOR (PASSENGER)"
38 Air mix door motor (rear) circuit malfunctionAT C - 7 3 , "DIAGNOSTIC PROCEDURE FOR AIR MIX DOOR
MOTOR (REAR)"
40 Ambient sensor circuit short
ATC-125, "Ambient Sensor Circuit"41 Ambient sensor circuit open
44 In-vehicle sensor motor circuit open
ATC-128, "
In-vehicle Sensor Circuit"46 In-vehicle sensor motor circuit short
50 Optical sensor (Driver) circuit open or short
ATC-131, "
Optical Sensor Circuit"52 Optical sensor (Passenger) circuit open or short
56 Intake sensor circuit short
ATC-133, "
Intake Sensor Circuit"57 Intake sensor circuit open
62 Defroster door motor circuit malfunctionAT C - 7 9 , "
Defroster Door Motor Circuit"
72 Intake door motor circuit malfunctionAT C - 7 6 , "Intake Door Motor Circuit"
80 CAN bus malfunction
LAN-5, "CAN COMMUNICATION"81 CAN BCM message missing
82 Intake door motor circuit malfunctionAT C - 7 6 , "
Intake Door Motor Circuit"
90 Stuck buttonATC-135, "FRONT AIR CONTROL"
92 Mode door motor circuit malfunctionAT C - 6 3 , "Mode Door Motor Circuit"

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-58
TROUBLE DIAGNOSIS
Revision: August 20072004 QX56
CHECKING TEMPERATURE INCREASE
1. Rotate temperature dial clockwise (driver or passenger) until
32°C (90°F) is displayed.
2. Check for hot 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 ATC-117, "
Insufficient Heating" . If
air mix door motor appears to be malfunctioning, go to ATC-69,
"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.
CHECK A/C SWITCH
1. Press A/C switch.
2. A/C switch indicator will turn ON.

Confirm that the compressor clutch engages (sound or visual
inspection).
If NG, go to trouble diagnosis procedure for ATC-104, "
Magnet
Clutch Circuit" .
If OK, continue with next check.
CHECKING AUTO MODE
1. Press AUTO switch.
2. Display should indicate AUTO.

If ambient temperature is warm, and selected temperature is
cool, confirm that the compressor clutch engages (sound or
visual inspection). (Discharge air and blower speed will
depend on ambient, in-vehicle, and set temperatures.)
If NG, go to trouble diagnosis procedure for ATC-60, "
Power Supply
and Ground Circuit for Front Air Control" , then if necessary, trouble
diagnosis procedure for ATC-104, "
Magnet Clutch Circuit" .
If all operational checks are OK (symptom cannot be duplicated), go
to malfunction Simulation Tests in AT C - 3 5 , "
How to Perform Trouble
Diagnosis for Quick and Accurate Repair" and perform tests as out-
lined to simulate driving conditions environment. If symptom appears. Refer to ATC-35, "
How to Perform Trou-
ble Diagnosis for Quick and Accurate Repair" , AT C - 3 5 , "SYMPTOM TABLE" and perform applicable trouble
diagnosis procedures.
WJIA0409E
WJIA0410E
WJIA0411E

TROUBLE DIAGNOSIS
ATC-59
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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

ATC-60
TROUBLE DIAGNOSIS
Revision: August 20072004 QX56
Power Supply and Ground Circuit for Front Air ControlEJ S00 2CD
SYMPTOM: A/C system does not come on.
INSPECTION FLOW
*1AT C - 6 0 , "Power Supply and Ground
Circuit for Front Air Control"
*2ATC-56, "Operational Check (Front)"
or AT C - 5 9 , "
Operational Check
(Rear)"
WJIA0764E

TROUBLE DIAGNOSIS
ATC-61
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Revision: August 20072004 QX56
COMPONENT DESCRIPTION
Front Air Control
The front air control has a built-in microcomputer which processes
information sent from various sensors needed for air conditioner
operation. The air mix door motors, mode door motor, intake door
motor, defroster door motor, blower motor and compressor are then
controlled.
The front air control is unitized with control mechanisms. When the
various switches and temperature dials are operated, data is input to
the front air control.
Self-diagnostic functions are also built into the front air control to pro-
vide quick check of malfunctions in the auto air conditioner system.
Potentio Temperature Control (PTC)
There are two PTCs (passenger and driver) built into the front air
control. They can be set at an interval of 0.5°C (1.0°F) in the 18°C
(65°F) to 30°C (85°F) temperature range by rotating the temperature
dial. The set temperature is displayed.
DIAGNOSTIC PROCEDURE FOR A/C SYSTEM
SYMPTOM: A/C system does not come on.
WJIA0759E
WJIA0413E
WJIA0414E