02 sensor INFINITI QX4 2001 Factory Service Manual

Overview of Control System=NBHA0015The control system consists of input sensors, switches, the automatic amplifier (microcomputer) and outputs.
The relationship of these components is shown in the diagram below:
RHA856H
Control OperationNBHA0016
RHA452GA
GI
MA
EM
LC
EC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
SC
EL
IDX
DESCRIPTION
Overview of Control System
HA-23

RHA464GA
RHA858H
Auto Amp. Terminals and Reference ValueNBHA0036INSPECTION OF AUTO AMP.NBHA0036S01IMeasure voltage between each terminal and body ground by
following ªAUTO AMP. INSPECTION TABLEº.
IPin connector terminal layout
RHA839H
AUTO AMP. INSPECTION TABLENBHA0036S02Without Navigation SystemNBHA0036S0201
TERMINAL
NO.ITEM CONDITIONVoltage
V
1 Intake sensor Ð Ð
2 Ambient sensor Ð Ð
3 In-vehicle sensor Ð Ð
6 ECM signal
Compressor: ON Approximately 0
Ccompressor: OFF Approximately 4.6
8 Intake door position switch Intake door positionFRESH Approximately 0
RECIRCULATION or 20%
FRESHApproximately 4.6
11 Sensor ground Ð Approximately 0
12 Sunload sensor Ð Ð
TROUBLE DIAGNOSES
Auto Amp. Terminals and Reference Value
HA-40

TERMINAL
NO.ITEM CONDITIONVoltage
V
13 Thermal transmitter
Engine coolant
temperatureApproximately 30ÉC (86ÉF) Approximately 9.4
Approximately 55ÉC (131ÉF) Approximately 6.5
Approximately 100ÉC
(212ÉF)Approximately 2.4
14 Ground (for Canada) Ð Approximately 0
16 A/C LAN signal Ð Approximately 5.5
18 Intake door position switch Intake door position20% FRE or RECIRCULA-
TIONApproximately 0
FRESH Approximately 4.6
19 Intake door position switch Intake door positionRECIRCULATION or
FRESHApproximately 0
20% FRE Approximately 4.6
21Power supply for mode door
motor and air mix door motorÐ Approximately 12
22 Compressor ON signal
CompressorON Approximately 0
OFF Approximately 4.6
24 Power supply for illumination
Lighting switchOFF Approximately 0
1st Approximately 12
25 Illumination ground Ð Approximately 0
26 Power supply for BAT
Ð BATTERY VOLTAGE
27 Power supply for IGN
Ð Approximately 12
28Power supply for intake door
motorIntake door positionFRESH Approximately 12
RECIRC Approximately 0
32 Ground Ð Approximately 0
33 Power source for A/C Ignition voltage feed back Approximately 12
34 Blower motor feed back Fan speed: Low Approximately7-10
35Fan control AMP. control sig-
nalFan speedLow, Middle low or Middle
highApproximately 2.5 -
3.0
High Approximately9-10
36Power supply for intake door
motorIntake door positionFRESH Approximately 0
RECIRC Approximately 12
With Navigation SystemNBHA0036S0202
TERMINAL
NO.ITEM CONDITIONVoltage
V
1 Intake sensor Ð Ð
2 Ambient sensor Ð Ð
3 In-vehicle sensor Ð Ð
GI
MA
EM
LC
EC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
SC
EL
IDX
TROUBLE DIAGNOSES
Auto Amp. Terminals and Reference Value (Cont'd)
HA-41

TERMINAL
NO.ITEM CONDITIONVoltage
V
6 Intake door position switch
Intake door positionRECIRCULATION Approximately 4.6
FRESH or 20% FRESH Approximately 0
7Multiplex communication sig-
nal
(AMP,NAVI)ÐÐ
8Multiplex communication sig-
nal
(NAVI,AMP)ÐÐ
9 Sensor ground
Ð Approximately 0
10 Sunload sensor Ð Ð
11 Thermal transmitter
Engine coolant
temperatureApproximately 30ÉC (86ÉF) Approximately 9.4
Approximately 55ÉC (131ÉF) Approximately 6.5
Approximately 100ÉC
(212ÉF)Approximately 2.4
Approximately 110ÉC
(230ÉF)Approximately 1.9
14 A/C LAN signal Ð Approximately 5.5
17 ECM signalCompressor: ON Approximately 0
Compressor: OFF Approximately 4.6
18 Intake door position switch Intake door positionFRESH Approximately 4.6
RECIRCULATION or 20%
FRESHApproximately 0
19 Intake door position switch Intake door position20% FRESH Approximately 4.6
RECIRCULATION or
FRESHApproximately 0
20Multiplex communication sig-
nal (CLK)ÐÐ
21 Power supply for door motor
Ð Approximately 12
22 Compressor ON signalCompressor: ON Approximately 0
Compressor: OFF Approximately 4.6
24 Power supply for BAT Ð BATTERY VOLTAGE
TROUBLE DIAGNOSES
Auto Amp. Terminals and Reference Value (Cont'd)
HA-42

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

5 STEP 2 - SENSOR CIRCUITS ARE CHECKED FOR OPEN OR SHORT CIRCUIT
Press(HOT) switch.
Does code No.
appear on the display?
RHA970DB
YesorNo
Ye s©GO TO 6.
No©GO TO 13.
6 STEP 3 - MODE DOOR AND INTAKE DOOR POSITIONS ARE CHECKED
Press(HOT) switch.
Does code No.
appear on the display?
RHA869DD
YesorNo
Ye s©GO TO 7.
No©GO TO 14.
TROUBLE DIAGNOSES
Self-diagnosis (Cont'd)
HA-46

9 STEP 5 - TEMPERATURE OF EACH SENSOR IS CHECKED
Press(HOT) switch.
Code No.
appears on the display.
RHA492A
©GO TO 10.
10 CHECK AMBIENT SENSOR
Press(DEF) switch one time, temperature detected by ambient sensor is indicated on the display.
ECON shown in display indicates negative temperature reading.
NOTE:
If temperature shown on display greatly differs from actual temperature, check sensor circuit first, then inspect sensor.
RHA499G
OK or NG
OK©GO TO 11.
NG©Go to Ambient Sensor Circuit (HA-129).
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-49

11 CHECK IN-VEHICLE SENSOR
Press(DEF) switch the second time, temperature detected by in-vehicle sensor is indicated on the display screen.
ECON shown in display indicates negative temperature reading.
NOTE:
If temperature shown on display greatly differs from actual temperature, check sensor circuit first, then inspect sensor.
RHA500G
OK or NG
OK©GO TO 12.
NG©Go to In-vehicle Sensor Circuit (HA-132).
12 CHECK INTAKE SENSOR
Press(DEF) switch the third time, temperature detected by intake sensor is indicated on the display.
NOTE:
If temperature shown on display greatly differs from actual temperature, check sensor circuit first, then inspect sensor.
RHA500GB
OK or NG
OK©1. Press
(DEF) switch the fourth time. Display returns to original presentation 5.
2. Turn ignition switch OFF or
(AUTO) switch ON.
3. END
NG©Go to Intake Sensor Circuit (HA-139).
TROUBLE DIAGNOSES
Self-diagnosis (Cont'd)
HA-50

13 CHECK MALFUNCTIONING SENSOR
Refer to the following chart for malfunctioning code No.
(If two or more sensors malfunction, corresponding code Nos. blink respectively two times.)
MTBL0083
*1: Conduct self-diagnosis STEP 2 under sunshine.
When conducting indoors, aim a light (more than 60W) at sunload sensor, otherwise Code No.
will indicate despite that
sunload sensor is functioning properly.
*2: HA-129
*3: HA-132
*4: HA-139
*5: HA-135
*6: HA-141
RHA455G
RHA501A
©INSPECTION END
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-51

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