2001 INFINITI QX4 engine

Self-diagnosis=NBHA0021INTRODUCTION AND GENERAL DESCRIPTIONNBHA0021S01The self-diagnostic system diagnoses sensors, door motors, blower motor, etc. by system line. Refer to appli-
cable sections (items) for details. Shifting from normal control to the self-diagnostic system is accomplished
by starting the engine (turning the ignition switch from ªOFFº to ªONº) and pressing ª
º switch for at least
5 seconds. The ª
º switch must be pressed within 10 seconds after starting the engine (ignition switch is
turned ªONº). This system will be canceled by either pressing
(AUTO) switch or turning the ignition switch
ªOFFº. Shifting from one step to another is accomplished by means of pushing
(HOT) or(COLD) switch,
as required.
Additionally shifting from STEP 5 to AUXILIARY MECHANISM is accomplished by means of pushing
(fan)
UP switch.
Without Navigation SystemNBHA0021S0101
RHA453GA
TROUBLE DIAGNOSES
Self-diagnosis
HA-44

STEP-BY-STEP PROCEDURE=NBHA0021S02Without Navigation SystemNBHA0021S0201
1 SET IN SELF-DIAGNOSTIC MODE
1. Turn ignition switch ON.
2. Set in self-diagnostic mode as follows. Within 10 seconds after starting engine (ignition switch is turned ªONº.), press
switch for at least 5 seconds.
©GO TO 2.
2 STEP 1 - ALL LEDs AND SEGMENT ARE CHECKED
Do all LEDs and segments illuminate?
RHA454G
YesorNo
Ye s©GO TO 3.
No©Malfunctioning
switch, LED or fluorescent display tube.
Replace A/C auto amp.
3 VERIFY ADVANCE TO SELF-DIAGNOSIS STEP 2
1. Press(HOT) switch.
2. Does advance to self-diagnosis STEP 2?
YesorNo
Ye s©GO TO 4.
No©Malfunctioning
(HOT) switch.
Replace A/C auto amp.
4 VERIFY RETURN TO SELF-DIAGNOSIS STEP 1
1. Press(COLD) switch.
2. Does return to self-diagnosis STEP 1?
YesorNo
Ye s©GO TO 5.
No©Malfunctioning
(COLD) switch.
Replace A/C auto amp.
GI
MA
EM
LC
EC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
SC
EL
IDX
TROUBLE DIAGNOSES
Self-diagnosis (Cont'd)
HA-45

7 STEP 4 - OPERATION OF EACH ACTUATOR IS CHECKED
Press(HOT) switch.
Engine running.
Press DEF switch, code No. of each actuator test is indicated on the display.
RHA495A
©GO TO 8.
GI
MA
EM
LC
EC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
SC
EL
IDX
TROUBLE DIAGNOSES
Self-diagnosis (Cont'd)
HA-47

INTRODUCTION AND GENERAL DESCRIPTIONNBHA0021S04The self-diagnostic system diagnoses sensors, door motors, blower motor, etc. by system line. Refer to appli-
cable sections (items) for details. Shifting from normal control to the self-diagnostic system is accomplished
by starting the engine (turning the ignition switch from ªOFFº to ªONº) and pressing ª
º switch for at least
5 seconds. The ª
º switch must be pressed within 10 seconds after starting the engine (ignition switch is
turned ªONº). This system will be canceled by either pressing
(AUTO) switch or turning the ignition switch
ªOFFº. Shifting from one step to another is accomplished by means of turning temperature dial, as required.
Additionally shifting from STEP 5 to AUXILIARY MECHANISM is accomplished by means of pushing
(fan)
UP switch.
With Navigation SystemNBHA0021S0401
RHA859H
TROUBLE DIAGNOSES
Self-diagnosis (Cont'd)
HA-54

STEP-BY-STEP PROCEDURENBHA0021S05With Navigation SystemNBHA0021S0501
1 SET IN SELF-DIAGNOSTIC MODE
1. Turn ignition switch ON.
2. Set in self-diagnostic mode as follows. Within 10 seconds after starting engine (ignition switch is turned ªONº.), press
switch for at least 5 seconds.
©GO TO 2.
2 STEP 1 - ALL LEDs AND DISPLAY SCREEN ARE CHECKED
When switch's LED and display are functioning properly in STEP-1, LED and display will come on.
RHA860H
OK or NG
OK©GO TO 3.
NG©Malfunctioning
switch, LED or fluorescent display tube.
Go to ªMain Power Supply and Ground Circuit Checkº, HA-72.
3 VERIFY ADVANCE TO SELF-DIAGNOSIS STEP 2
1. Turn temperature dial clockwise.
2. Does advance to self-diagnosis STEP 2?
YesorNo
Ye s©GO TO 4.
No©Malfunctioning temperature dial.
Check Display & NAVI control unit.
4 VERIFY RETURN TO SELF-DIAGNOSIS STEP 1
1. Turn temperature dial counterclockwise.
2. Does return to self-diagnosis STEP 1?
YesorNo
Ye s©GO TO 5.
No©Malfunctioning temperature dial.
Check Display & NAVI control unit.
GI
MA
EM
LC
EC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
SC
EL
IDX
TROUBLE DIAGNOSES
Self-diagnosis (Cont'd)
HA-55

7 STEP 4 - OPERATION OF EACH ACTUATOR IS CHECKED
Turn temperature dial clockwise.
Engine running.
Press DEF switch, code No. of each actuator test is indicated on the display.
RHA495A
©GO TO 8.
GI
MA
EM
LC
EC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
SC
EL
IDX
TROUBLE DIAGNOSES
Self-diagnosis (Cont'd)
HA-57

Operational CheckNBHA0019The purpose of the operational check is to confirm that the system
operates properly.
CONDITIONS:NBHA0019S01IEngine running and at normal operating temperature.
RHA864H
RHA335HA
PROCEDURE:NBHA0019S021. Check Memory FunctionNBHA0019S02011. Set the temperature 85ÉF or 32ÉC.
2. Press OFF switch.
3. Turn the ignition off.
4. Turn the ignition on.
5. Press the AUTO switch.
6. Confirm that the set temperature remains at previous tempera-
ture.
7. Press OFF switch.
If NG, go to trouble diagnosis procedure for memory function (HA-
126).
If OK, continue with next check.
RHA457GA
RHA329HA
2. Check BlowerNBHA0019S02021. Press fan switch (up side) one time.
Blower should operate on low speed.
The fan symbol should have one blade lit
.
2. Press fan switch (up side) one more time, and continue check-
ing blower speed and fan symbol until all speeds are checked.
3. Leave blower on MAX speed
.
If NG, go to trouble diagnosis procedure for blower motor (HA-95).
If OK, continue with next check.
TROUBLE DIAGNOSES
Operational Check
HA-66

SYSTEM DESCRIPTION=NBHA0062Component partsNBHA0062S01Fan speed control system components are:
1) Auto amp.
2) Fan control amp.
3) A/C LAN system (PBR built-in mode door motor and air mix door motor)
4) In-vehicle sensor
5) Ambient sensor
6) Sunload sensor
7) Intake sensor
System OperationNBHA0062S02
SHA006FF
Automatic ModeNBHA0062S03In the automatic mode, the blower motor speed is calculated by the automatic amplifier based on inputs from
the PBR, in-vehicle sensor, sunload sensor, intake sensor and ambient sensor. The blower motor applied
voltage ranges from approximately 5 volts (lowest speed) to 12 volts (highest speed).
The control blower speed (in the range of 5 to 12V), the automatic amplifier supplies a gate voltage to the fan
control amplifier. Based on this voltage, the fan control amplifier controls the voltage supplied to the blower
motor.
Starting Fan Speed ControlNBHA0062S04Start Up From ªCOLD SOAKº Condition (Automatic mode)NBHA0062S0401In a cold start up condition where the engine coolant temperature is below 50ÉC (122ÉF), the blower will not
operate for a short period of time (up to 126 seconds). The exact start delay time varies depending on the
ambient and engine coolant temperature.
In the most extreme case (very low ambient) the blower starting delay will be 126 seconds as described above.
After this delay, the blower will operate at low speed until the engine coolant temperature rises above 55ÉC
(131ÉF), at which time the blower speed will increase to the objective speed.
Start Up From Normal or ªHOT SOAKº Condition (Automatic mode)
NBHA0062S0402The blower will begin operation momentarily after the AUTO button is pushed. The blower speed will gradu-
ally rise to the objective speed over a time period of 3 seconds or less (actual time depends on the objective
blower speed).
GI
MA
EM
LC
EC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
SC
EL
IDX
TROUBLE DIAGNOSES
Blower Motor (Cont'd)
HA-97