INFINITI QX4 2001 Factory Service Manual

Insufficient Cooling
TROUBLE DIAGNOSIS PROCEDURE FOR INSUFFICIENT COOLING=NBHA0096SYMPTOM:
IInsufficient cooling
Inspection FlowNBHA0096S01Without Navigation SystemNBHA0096S0101
SHA190FC
*1: HA-44
*2: HA-85
*3: HA-116
*4: HA-53
*5: STEP-BY-STEP PROCEDURE
(HA-45), see No. 13.*6: HA-77
*7: HA-89
*8: HA-97
*9: HA-106
*10: HA-114*11: HA-66
*12: HA-45
*13: HA-2
*14: MA-13
*15: LC-20
TROUBLE DIAGNOSES
Insufficient Cooling
HA-112

With Navigation SystemNBHA0096S0102
RHA881H
*1: HA-44
*2: HA-85
*3: HA-116
*4: HA-53
*5: STEP-BY-STEP PROCEDURE
(HA-45), see No. 13.*6: HA-77
*7: HA-89
*8: HA-97
*9: HA-106
*10: HA-114*11: HA-66
*12: HA-45
*13: HA-2
*14: MA-13
*15: LC-20
GI
MA
EM
LC
EC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
SC
EL
IDX
TROUBLE DIAGNOSES
Insufficient Cooling (Cont'd)
HA-113

PERFORMANCE TEST DIAGNOSESNBHA0030
SHA893E
*1: HA-116
*2: HA-116*3: HA-116
*4: HA-85*5: HA-85
TROUBLE DIAGNOSES
Insufficient Cooling (Cont'd)
HA-114

RHA576H
*1: HA-149 *2: HA-95 *3: MA-13
GI
MA
EM
LC
EC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
SC
EL
IDX
TROUBLE DIAGNOSES
Insufficient Cooling (Cont'd)
HA-115

PERFORMANCE CHARTNBHA0031Test ConditionNBHA0031S01Testing must be performed as follows:
Vehicle location Indoors or in the shade (in a well-ventilated place)
Doors Closed
Door window Open
Hood Open
TEMP. Max. COLD
Mode switch
(Ventilation) set
REC switch
(Recirculation) set
(blower) speed Max. speed set
Engine speed Idle speed
Operate the air conditioning system for 10 minutes before taking measurements.
Test ReadingNBHA0031S02Recirculating-to-discharge Air Temperature TableNBHA0031S0201
Inside air (Recirculating air) at blower assembly inlet
Discharge air temperature at center ventilator
ÉC (ÉF) Relative humidity
%Air temperature
ÉC (ÉF)
50-6025 (77) 6.0 - 9.0 (43 - 48)
30 (86) 10.0 - 13.6 (50 - 56)
35 (95) 15.2 - 19.5 (59 - 67)
40 (104) 22.5 - 27.1 (73 - 81)
60-7025 (77) 9.0 - 12.2 (48 - 54)
30 (86) 13.6 - 17.2 (56 - 63)
35 (95) 19.5 - 23.7 (67 - 75)
40 (104) 27.1 - 32.3 (81 - 90)
Ambient Air Temperature-to-operating Pressure TableNBHA0031S0202
Ambient air
High-pressure (Discharge side)
kPa (kg/cm
2, psi)Low-pressure (Suction side)
kPa (kg/cm2, psi) Relative humidity
%Air temperature
ÉC (ÉF)
50-7025 (77)1,226 - 1,638
(12.5 - 16.7, 178 - 237)172 - 250 (1.75 - 2.55, 25 - 36)
30 (86)1,422 - 1,883
(14.5 - 19.2, 206 - 273)196 - 275 (2.0 - 2.8, 28 - 40)
35 (95)1,657 - 2,187
(16.9 - 22.3, 240 - 317)231 - 309 (2.35 - 3.15, 33 - 45)
40 (104)1,922 - 2,501
(19.6 - 25.5, 279 - 363)280 - 373 (2.85 - 3.8, 41 - 54)
TROUBLE DIAGNOSES FOR ABNORMAL PRESSURENBHA0032Whenever system's high and/or low side pressure is abnormal, diagnose using a manifold gauge. The marker
above the gauge scale in the following tables indicates the standard (normal) pressure range. Since the stan-
dard (normal) pressure, however, differs from vehicle to vehicle, refer to HA-116 (ªAmbient air temperature-
to-operating pressure tableº).
TROUBLE DIAGNOSES
Insufficient Cooling (Cont'd)
HA-116

Both High- and Low-pressure Sides are Too High.NBHA0032S01
Gauge indication Refrigerant cycle Probable cause Corrective action
Both high- and low-pressure sides
are too high.
AC359A
IPressure is reduced soon
after water is splashed on
condenser.Excessive refrigerant charge
in refrigeration cycleReduce refrigerant until
specified pressure is
obtained.
Air suction by cooling fan is
insufficient.Insufficient condenser cool-
ing performance
"
1. Condenser fins are
clogged.
2. Improper fan rotation of
cooling fanIClean condenser.
ICheck and repair cooling
fan as necessary.
ILow-pressure pipe is not
cold.
IWhen compressor is
stopped high-pressure
value quickly drops by
approximately 196 kPa (2
kg/cm
2, 28 psi). It then
decreases gradually there-
after.Poor heat exchange in con-
denser
(After compressor operation
stops, high pressure
decreases too slowly.)
"
Air in refrigeration cycleEvacuate repeatedly and
recharge system.
Engine tends to overheat. Engine cooling systems mal-
function.Check and repair each
engine cooling system.
IAn area of the low-pres-
sure pipe is colder than
areas near the evaporator
outlet.
IPlates are sometimes cov-
ered with frost.IExcessive liquid refrigerant
on low-pressure side
IExcessive refrigerant dis-
charge flow
IExpansion valve is open a
little compared with the
specification.
"
1. Improper thermal valve
installation
2. Improper expansion valve
adjustmentReplace expansion valve.
High-pressure Side is Too High and Low-pressure Side is Too Low.NBHA0032S02
Gauge indication Refrigerant cycle Probable cause Corrective action
High-pressure side is too high and
low-pressure side is too low.
AC360A
Upper side of condenser and
high-pressure side are hot,
however, liquid tank is not so
hot.High-pressure tube or parts
located between compressor
and condenser are clogged
or crushed.ICheck and repair or
replace malfunctioning
parts.
ICheck lubricant for con-
tamination.
GI
MA
EM
LC
EC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
SC
EL
IDX
TROUBLE DIAGNOSES
Insufficient Cooling (Cont'd)
HA-117

High-pressure Side is Too Low and Low-pressure Side is Too High.NBHA0032S03
Gauge indication Refrigerant cycle Probable cause Corrective action
High-pressure side is too low and
low-pressure side is too high.
AC356A
High and low-pressure sides
become equal soon after
compressor operation stops.Compressor pressure opera-
tion is improper.
"
Damaged inside compressor
packingsReplace compressor.
No temperature difference
between high and low-pres-
sure sidesCompressor pressure opera-
tion is improper.
"
Damaged inside compressor
packings.Replace compressor.
TROUBLE DIAGNOSES
Insufficient Cooling (Cont'd)
HA-118

Both High- and Low-pressure Sides are Too Low.NBHA0032S04
Gauge indication Refrigerant cycle Probable cause Corrective action
Both high- and low-pressure sides
are too low.
AC353A
IThere is a big temperature
difference between
receiver drier outlet and
inlet. Outlet temperature is
extremely low.
ILiquid tank inlet and
expansion valve are
frosted.Compressor discharge
capacity does not change.
(Compressor stroke is set at
maximum.)IReplace liquid tank.
ICheck lubricant for con-
tamination.
ITemperature of expansion
valve inlet is extremely low
as compared with areas
near liquid tank.
IExpansion valve inlet may
be frosted.
ITemperature difference
occurs somewhere in high-
pressure sideHigh-pressure pipe located
between receiver drier and
expansion valve is clogged.ICheck and repair malfunc-
tioning parts.
ICheck lubricant for con-
tamination.
IExpansion valve and liquid
tank are warm or only cool
when touched.Low refrigerant charge
"
Leaking fittings or compo-
nentsCheck refrigerant for leaks.
Refer to ªChecking Refriger-
ant Leaksº, HA-155.
There is a big temperature
difference between expan-
sion valve inlet and outlet
while the valve itself is
frosted.Expansion valve closes a
little compared with the
specification.
"
1. Improper expansion valve
adjustment
2. Malfunctioning thermal
valve
3. Outlet and inlet may be
clogged.IRemove foreign particles
by using compressed air.
ICheck lubricant for con-
tamination.
An area of the low-pressure
pipe is colder than areas
near the evaporator outlet.Low-pressure pipe is clogged
or crushed.ICheck and repair malfunc-
tioning parts.
ICheck lubricant for con-
tamination.
Air flow volume is not
enough or is too low.Evaporator is frozen.
"
Compressor discharge
capacity does not change.
(Compressor stroke is set at
maximum length.)Replace compressor.
GI
MA
EM
LC
EC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
SC
EL
IDX
TROUBLE DIAGNOSES
Insufficient Cooling (Cont'd)
HA-119

Low-pressure Side Sometimes Becomes Negative.NBHA0032S05
Gauge indication Refrigerant cycle Probable cause Corrective action
Low-pressure side sometimes
becomes negative.
AC354A
IAir conditioning system
does not function and
does not cyclically cool the
compartment air.
IThe system constantly
functions for a certain
period of time after com-
pressor is stopped and
restarted.Refrigerant does not dis-
charge cyclically.
"
Moisture is frozen at expan-
sion valve outlet and inlet.
"
Water is mixed with refriger-
ant.IDrain water from refriger-
ant or replace refrigerant.
IReplace liquid tank.
Low-pressure Side Becomes Negative.NBHA0032S06
Gauge indication Refrigerant cycle Probable cause Corrective action
Low-pressure side becomes nega-
tive.
AC362A
Liquid tank or front/rear side
of expansion valve's pipe is
frosted or dewed.High-pressure side is closed
and refrigerant does not flow.
"
Expansion valve or liquid
tank is frosted.Leave the system at rest
until no frost is present. Start
it again to check whether or
not the problem is caused by
water or foreign particles.
IIf water is the cause, ini-
tially cooling is okay. Then
the water freezes causing
a blockage. Drain water
from refrigerant or replace
refrigerant.
IIf due to foreign particles,
remove expansion valve
and remove the particles
with dry and compressed
air (not shop air).
IIf either of the above
methods cannot correct
the problem, replace
expansion valve.
IReplace liquid tank.
ICheck lubricant for con-
tamination.
TROUBLE DIAGNOSES
Insufficient Cooling (Cont'd)
HA-120

Insufficient Heating
TROUBLE DIAGNOSIS PROCEDURE FOR INSUFFICIENT HEATING=NBHA0097SYMPTOM:
IInsufficient heating
Inspection FlowNBHA0097S01Without Navigation SystemNBHA0097S0101
SHA894EA
*1: HA-66
*2: HA-44
*3: HA-45
*4: HA-45
*5: HA-85*6: STEP-BY-STEP PROCEDURE
(HA-45), see No. 13.
*7: HA-78
*8: HA-90
*9: HA-98*10: HA-82
*11: MA-14
*12: LC-11
*13: LC-16
GI
MA
EM
LC
EC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
SC
EL
IDX
TROUBLE DIAGNOSES
Insufficient Heating
HA-121