INFINITI QX4 2001 Factory Service Manual

8 CHECK POWER SUPPLY FOR BLOWER MOTOR
Disconnect blower motor harness connector.
Do approx. 12 volts exist between blower motor harness terminal No. 1 and body ground?
RHA091G
YesorNo
Ye s©GO TO 9.
No©Check power supply circuit and 15A fuses (Nos. 1 and 2, located in the fuse
block).
IIf OK, check for open circuit in wiring harness.
Repair or replace as necessary.
IIf NG, replace fuse and check wiring harness for short circuit.
Repair or replace as necessary.
9 CHECK CIRCUIT CONTINUITY BETWEEN BLOWER MOTOR AND FAN CONTROL AMP.
Disconnect blower motor connector and auto amp. (LCU) connector.
Check circuit continuity between blower motor harness terminal No. 2 and fan control amp. harness terminal No. 3.
RHA472G
OK or NG
OK©Check blower motor. (Refer to HA-103.)
1. If NG, replace blower motor.
2. Go to self-diagnosis step-by-step procedure (HA-45) and perform self-diagnosis STEP
4.
Confirm that blower motor operation is normal.
NG©Repair harness or connector.
TROUBLE DIAGNOSES
Blower Motor (Cont'd)
HA-102

10 CHECK BLOWER MOTOR CIRCUIT BETWEEN BLOWER MOTOR AND AUTO AMP. (LCU)
Check circuit continuity between blower motor harness terminal No. 2 and auto amp. (LCU) harness terminal No. 34.
RHA827H
Continuity should exist.
If OK, check harness for short.
OK or NG
OK©INSPECTION END
NG©Repair harness or connector.
RHA941F
COMPONENT INSPECTIONNBHA0065Blower MotorNBHA0065S01Confirm smooth rotation of the blower motor.
IEnsure that there are no foreign particles inside the intake unit.
RHA828H
Fan Control AmplifierNBHA0065S02Check continuity between terminal Nos. 1 and 2.
Terminal No. Continuity
1-2 Yes
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TROUBLE DIAGNOSES
Blower Motor (Cont'd)
HA-103

Magnet Clutch
TROUBLE DIAGNOSIS PROCEDURE FOR MAGNET CLUTCH=NBHA0095SYMPTOM:
IMagnet clutch does not engage.
Inspection FlowNBHA0095S01Without Navigation SystemNBHA0095S0101
SHA249F
*1: STEP-BY-STEP PROCEDURE
(HA-44)
*2: HA-129
*3: HA-132
*4: HA-135
*5: HA-141*6: STEP-BY-STEP PROCEDURE
(HA-45), see No. 13.
*7: HA-106
*8: HA-150
*9: HA-155
*10: HA-66*11: HA-45
*12: HA-66
*13: HA-65
*14: HA-139
TROUBLE DIAGNOSES
Magnet Clutch
HA-104

With Navigation SystemNBHA0095S0102
RHA876H
*1: STEP-BY-STEP PROCEDURE
(HA-44)
*2: HA-129
*3: HA-132
*4: HA-135
*5: HA-141*6: STEP-BY-STEP PROCEDURE
(HA-45), see No. 13.
*7: HA-106
*8: HA-150
*9: HA-155
*10: HA-66*11: HA-45
*12: HA-66
*13: HA-65
*14: HA-139
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TROUBLE DIAGNOSES
Magnet Clutch (Cont'd)
HA-105

RHA094GB
SYSTEM DESCRIPTION=NBHA0066Auto amplifier controls compressor operation by ambient tempera-
ture and signal from ECM.
Low Temperature Protection ControlNBHA0066S01Auto amplifier will turn the compressor ªONº or ªOFFº as deter-
mined by a signal detected by ambient sensor.
When ambient temperatures are greater than ±2ÉC (28ÉF), the
compressor turns ªONº. The compressor turns ªOFFº when ambi-
ent temperatures are less than þ5ÉC (23ÉF).
RHA877H
DIAGNOSTIC PROCEDURENBHA0067SYMPTOM: Magnet clutch does not engage when AUTO
switch is ON.
1 CHECK POWER SUPPLY FOR COMPRESSOR
Disconnect compressor harness connector. Do approx. 12 volts exist between compressor harness terminal No. 1 and
body ground?
RHA096G
YesorNo
Ye s©Check magnet clutch coil.
1. If NG, replace magnet clutch. Refer to HA-150.
2. Go to self-diagnosis step-by-step procedure (HA-45) and perform self-diagnosis STEP
4.
Confirm that magnet clutch operation is normal.
No©Disconnect A/C relay. And GO TO 2.
TROUBLE DIAGNOSES
Magnet Clutch (Cont'd)
HA-106

2 CHECK CIRCUIT CONTINUITY BETWEEN A/C RELAY AND COMPRESSOR
Check circuit continuity between A/C relay harness terminal No. 5 and compressor harness terminal No. 1.
RHA748FB
Continuity should exist.
If OK, check harness for short.
OK or NG
OK©GO TO 3.
NG©Repair harness or connector.
3 CHECK POWER SUPPLY FOR A/C RELAY
Disconnect A/C relay.
Do approx. 12 volts exist between A/C relay harness terminal Nos. 2, 3 and body ground?
RHA614F
YesorNo
Ye s©GO TO 4.
No©Check power supply circuit and 7.5A (No. 6) fuse at fuse block.
Refer to EL-14, ªWiring Diagram Ð POWER к.
IIf OK, check for open circuit in wiring harness.
Repair or replace as necessary.
IIf NG, replace fuse and check wiring harness for short circuit.
Repair or replace as necessary.
4 CHECK A/C RELAY AFTER DISCONNECTING IT
Refer to HA-110.
OK or NG
OK©Reconnect A/C relay. And GO TO 5.
NG©1. Replace A/C relay.
2. Go to self-diagnosis step-by-step procedure (HA-45) and perform self-diagnosis STEP
4.
Confirm that magnet clutch operation is normal.
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TROUBLE DIAGNOSES
Magnet Clutch (Cont'd)
HA-107

5 CHECK COIL SIDE CIRCUIT OF A/C RELAY
Do approx. 12 volts exist between ECM harness terminal No. 27 and body ground?
RHA482GG
YesorNo
Ye s©GO TO 6.
No©Disconnect A/C relay.
Disconnect ECM harness connector.
GO TO 11.
6 CHECK VOLTAGE FOR ECM
Do approx. 12 volts exist between ECM harness terminal No. 45 and body ground?
RHA701FJ
YesorNo
Ye s©Disconnect ECM harness connector.
Disconnect dual-pressure switch harness connector.
GO TO 7.
No©Check ECM. Refer to EC-127, ªECM Terminals and Reference Valueº.
TROUBLE DIAGNOSES
Magnet Clutch (Cont'd)
HA-108

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

10 CHECK CIRCUIT CONTINUITY BETWEEN ECM AND AUTO AMP.
Check circuit continuity between ECM harness terminal No. 51 and auto amp. harness terminal No. 6 (17).
RHA879H
Continuity should exist.
If OK, check harness for short.
OK or NG
OK©Replace auto amp.
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.
11 CHECK CIRCUIT CONTINUITY BETWEEN A/C RELAY AND ECM
Check circuit continuity between A/C relay harness terminal No. 1 and ECM harness terminal No. 27.
RHA474GB
Continuity should exist.
OK or NG
OK©Check harness for short.
NG©Repair harness or connector.
SEF090M
COMPONENT INSPECTIONNBHA0068A/C RelayNBHA0068S01Check continuity between terminal Nos. 3 and 5.
Conditions Continuity
12V direct current supply between terminal Nos. 1 and 2 Yes
No current supply No
If NG, replace relay.
TROUBLE DIAGNOSES
Magnet Clutch (Cont'd)
HA-110

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