02 sensor INFINITI QX4 2001 Factory Service Manual

7 CHECK CIRCUIT CONTINUITY BETWEEN ECM AND AUTO AMP.
Check circuit continuity between ECM harness terminal No. 45 and auto amp. harness terminal No. 22.
RHA878H
Continuity should exist.
If OK, check harness for short.
OK or NG
OK©GO TO 8.
NG©1. Repair harness or connector.
2. Go to ªSTEP-BY-STEP PROCEDUREº, ªSelf-diagnosisº, HA-45 and perform self-diag-
nosis STEP 4.
Confirm that magnet clutch operation is normal.
8 CHECK REFRIGERANT PRESSURE SENSOR
Refer to EC-641, ªDiagnostic Procedureº, HA-111.
OK or NG
OK©GO TO 9.
NG©Replace refrigerant pressure sensor.
9 CHECK VOLTAGE FOR ECM
Check 4.6 volts exist between ECM harness terminal No. 51 and body ground?
RHA482GG
YesorNo
Ye s©Check ECM. Refer to EC-127, ªECM Terminal and Reference Valueº.
No©GO TO 10.
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TROUBLE DIAGNOSES
Magnet Clutch (Cont'd)
HA-109

RHA880H
SHA315F
Refrigerant Pressure SensorNBHA0068S02Make sure that higher A/C refrigerant pressure results in higher
refrigerant-pressure sensor output voltage.
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TROUBLE DIAGNOSES
Magnet Clutch (Cont'd)
HA-111

With Navigation SystemNBHA0103S0102
RHA887H
*1: HA-72 *2: HA-66 *3: HA-45
RHA050G
Ambient Sensor Circuit
COMPONENT DESCRIPTIONNBHA0039The ambient sensor is attached in front of the driver's side con-
denser. It detects ambient temperature and converts it into a resis-
tance value which is then input into the auto amplifier.
AMBIENT TEMPERATURE INPUT PROCESSNBHA0040The automatic amplifier includes a ªprocessing circuitº for the ambi-
ent sensor input. However, when the temperature detected by the
ambient sensor increases quickly, the processing circuit retards the
auto amp. function. It only allows the auto amp. to recognize an
ambient temperature increase of 0.33ÉC (0.6ÉF) per 100 seconds.
As an example, consider stopping for a cup of coffee after high
speed driving. Although the actual ambient temperature has not
changed, the temperature detected by the ambient sensor will
increase. This is because the heat from the engine compartment
can radiate to the front grille area, location of the ambient sensor.
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TROUBLE DIAGNOSES
ECON (ECONOMY) Mode (Cont'd)
HA-129

RHA051GE
DIAGNOSTIC PROCEDURENBHA0041SYMPTOM: Ambient sensor circuit is open or shorted. (or
þ
is indicated on the display as a result of conducting Self-
diagnosis STEP 2.)
1 CHECK VOLTAGE BETWEEN AMBIENT SENSOR HARNESS CONNECTOR AND BODY GROUND
Disconnect ambient sensor harness connector.
Do approx. 5 volts exist between ambient sensor harness terminal No. 1 and body ground?
RHA052G
YesorNo
Ye s©GO TO 2.
No©GO TO 4.
2 CHECK AMBIENT SENSOR CIRCUIT BETWEEN AMBIENT SENSOR AND AUTO AMP. (LCU)
1. Disconnect auto amp. (LCU) harness connector.
2. Check circuit continuity between ambient sensor harness terminal No. 2 and auto amp. (LCU) harness terminal No. 11
or 9.
RHA829H
Continuity should exist.
If OK, check harness for short.
OK or NG
OK©GO TO 3.
NG©Repair harness or connector.
TROUBLE DIAGNOSES
Ambient Sensor Circuit (Cont'd)
HA-130

3 CHECK AMBIENT SENSOR
Refer to HA-131.
OK or NG
OK©1. Replace auto amp. (LCU).
2. Go to self-diagnosis step-by-step procedure (HA-45) and perform self-diagnosis STEP
2.
Confirm that code No. 20 is displayed.
NG©Replace ambient sensor.
4 CHECK AMBIENT SENSOR CIRCUIT BETWEEN AMBIENT SENSOR AND AUTO AMP. (LCU)
1. Disconnect auto amp. (LCU) harness connector.
2. Check circuit continuity between ambient sensor harness terminal No. 1 and auto amp. (LCU) harness terminal No. 2.
RHA830H
Continuity should exist.
If OK, check harness for short.
OK or NG
OK©1. Replace auto amp. (LCU).
2. Go to self-diagnosis step-by-step procedure (HA-45) and perform self-diagnosis STEP
2.
Confirm that code No. 20 is displayed.
NG©Repair harness or connector.
SHA304F
COMPONENT INSPECTIONNBHA0042Ambient SensorNBHA0042S01After disconnecting ambient sensor harness connector, measure
resistance between terminals 2 and 1 at sensor harness side, using
the table below.
Temperature ÉC (ÉF) Resistance kW
þ15 (5) 12.73
þ10 (14) 9.92
þ5 (23) 7.80
0 (32) 6.19
5 (41) 4.95
10 (50) 3.99
15 (59) 3.24
20 (68) 2.65
25 (77) 2.19
30 (86) 1.81
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Ambient Sensor Circuit (Cont'd)
HA-131

Temperature ÉC (ÉF) Resistance kW
35 (95) 1.51
40 (104) 1.27
45 (113) 1.07
If NG, replace ambient sensor.
RHA103G
In-vehicle Sensor Circuit
COMPONENT DESCRIPTIONNBHA0043In-vehicle sensorNBHA0043S01The in-vehicle sensor is located on instrument lower panel. It con-
verts variations in temperature of compartment air drawn from the
aspirator into a resistance value. It is then input into the auto
amplifier.
RHA636F
RHA482A
AspiratorNBHA0043S02The aspirator is located in front of heater unit. It produces vacuum
pressure due to air discharged from the heater unit, continuously
taking compartment air in the aspirator.
RHA056GH
DIAGNOSTIC PROCEDURENBHA0044SYMPTOM: In-vehicle sensor circuit is open or shorted. (or
þ
is indicated on the display as a result of conducting Self-
diagnosis STEP 2.)
TROUBLE DIAGNOSES
Ambient Sensor Circuit (Cont'd)
HA-132

1 CHECK IN-VEHICLE SENSOR CIRCUIT BETWEEN IN-VEHICLE SENSOR AND BODY GROUND
Disconnect in-vehicle sensor harness connector.
Do approx. 5 volts exist between in-vehicle sensor harness terminal No. 1 and body ground?
RHA477G
YesorNo
Ye s©GO TO 2.
No©GO TO 4.
2 CHECK IN-VEHICLE SENSOR CIRCUIT BETWEEN IN-VEHICLE SENSOR AND AUTO AMP. (LCU)
1. Disconnect auto amp. (LCU) harness connector.
2. Check circuit continuity between in-vehicle sensor harness terminal No. 2 and auto amp. (LCU) harness terminal No.
11 or 9.
RHA831H
Continuity should exist.
If OK, check harness for short.
OK or NG
OK©GO TO 3.
NG©Repair harness or connector.
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TROUBLE DIAGNOSES
In-vehicle Sensor Circuit (Cont'd)
HA-133

3 CHECK IN-VEHICLE SENSOR
Refer to HA-135.
OK or NG
OK©1. Replace auto amp.
2. Go to self-diagnosis step-by-step procedure (HA-45) and perform self-diagnosis STEP
2.
Confirm that code No. 20 is displayed.
NG©1. Replace in-vehicle sensor.
2. Go to self-diagnosis step-by-step procedure (HA-45) and perform self-diagnosis STEP
2.
Confirm that code No. 20 is displayed.
4 CHECK IN-VEHICLE SENSOR CIRCUIT BETWEEN AMBIENT SENSOR AND AUTO AMP. (LCU)
1. Disconnect auto amp. (LCU) harness connector.
2. Check circuit continuity between in-vehicle sensor harness terminal No. 1 and auto amp. (LCU) harness terminal No. 3.
RHA832H
Continuity should exist.
If OK, check harness for short.
OK or NG
OK©1. Replace auto amp. (LCU).
2. Go to self-diagnosis step-by-step procedure (HA-45) and perform self-diagnosis STEP
2.
Confirm that code No. 20 is displayed.
NG©Repair harness or connector.
TROUBLE DIAGNOSES
In-vehicle Sensor Circuit (Cont'd)
HA-134

RHA060GB
COMPONENT INSPECTIONNBHA0045In-vehicle SensorNBHA0045S01After disconnecting in-vehicle sensor harness connector, measure
resistance between terminals 1 and 2 at sensor harness side, using
the table below.
Temperature ÉC (ÉF) Resistance kW
þ15 (5) 12.73
þ10 (14) 9.92
þ5 (23) 7.80
0 (32) 6.19
5 (41) 4.95
10 (50) 3.99
15 (59) 3.24
20 (68) 2.65
25 (77) 2.19
30 (86) 1.81
35 (95) 1.51
40 (104) 1.27
45 (113) 1.07
If NG, replace in-vehicle sensor.
RHA639F
Sunload Sensor Circuit
COMPONENT DESCRIPTIONNBHA0046The sunload sensor is located on the right defroster grille. 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 auto amplifier.
SUNLOAD INPUT PROCESSNBHA0047The auto amp. also includes a processing circuit which ªaverageº
the variations in detected sunload over a period of time. This pre-
vents drastic swings in the ATC system operation due to small or
quick variations in detected sunload.
For example, consider driving along a road bordered by an occa-
sional group of large trees. The sunload detected by the sunload
sensor will vary whenever the trees obstruct the sunlight. The pro-
cessing circuit averages the detected sunload over a period of
time, so that the (insignificant) effect of the trees momentarily
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TROUBLE DIAGNOSES
In-vehicle Sensor Circuit (Cont'd)
HA-135

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 accordingly.
SHA301FA
DIAGNOSTIC PROCEDURENBHA0048SYMPTOM: Sunload sensor circuit is open or shorted. (or
þ
is indicated on the display as a result of conducting Self-
diagnosis STEP 2.)
1 CHECK SUNLOAD SENSOR CIRCUIT BETWEEN SUNLOAD SENSOR AND BODY GROUND
Disconnect sunload sensor harness connector.
Do approx. 5 volts exist between sunload sensor harness terminal No. 1 and body ground?
RHA062G
YesorNo
Ye s©GO TO 2.
No©GO TO 4.
TROUBLE DIAGNOSES
Sunload Sensor Circuit (Cont'd)
HA-136