2007 NISSAN 350Z Automatic Air Conditioner Workshop Manual

TROUBLE DIAGNOSIS
ATC-81
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AT C
Revision: 2006 November2007 350Z
Insufficient CoolingNJS00016
SYMPTOM: Insufficient cooling
INSPECTION FLOW
SJIA1130E

ATC-82
TROUBLE DIAGNOSIS
Revision: 2006 November2007 350Z
*1ATC-46, "FUNCTION CONFIRMA-
TION PROCEDURE", see No. 1.*2AT C - 6 3 , "
Air Mix Door Motor Circuit"*3AT C - 8 5 , "Test Reading"
*4ATC-50, "AUXILIARY MECHA-
NISM: TEMPERATURE SETTING
TRIMMER"
*5AT C - 4 6 , "FUNCTION CONFIRMA-
TION PROCEDURE", see No. 9.*6AT C - 5 6 , "
LAN System Circuit"
*7ATC-69, "Blower Motor Circuit"*8AT C - 7 4 , "Magnet Clutch Circuit"*9AT C - 8 3 , "PERFORMANCE TEST
DIAGNOSIS"
*10ATC-53, "Operational Check"*11AT C - 4 6 , "FUNCTION CONFIRMA-
TION PROCEDURE", see No. 5 to
7.*12AT C - 5 , "
CONTAMINATED REFRIG-
ERANT"
*13EM-12, "Checking Drive Belts"*14EC-543, "SYSTEM DESCRIPTION"

TROUBLE DIAGNOSIS
ATC-83
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F
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K
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MA
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AT C
Revision: 2006 November2007 350Z
PERFORMANCE TEST DIAGNOSIS
*1AT C - 8 5 , "PERFORMANCE CHART"*2ATC-85, "PERFORMANCE CHART"*3AT C - 8 6 , "TROUBLE DIAGNOSIS
FOR UNUSUAL PRESSURE"
*4AT C - 6 3 , "Air Mix Door Motor Circuit"
SJIA1226E

ATC-84
TROUBLE DIAGNOSIS
Revision: 2006 November2007 350Z
*1ATC-125, "Removal and Installation
of Compressor"
*2ATC-69, "Blower Motor Circuit"*3EM-12, "Checking Drive Belts"
SJIA1642E

TROUBLE DIAGNOSIS
ATC-85
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AT C
Revision: 2006 November2007 350Z
PERFORMANCE CHART
Test Condition
Testing must be performed as follows:
Test Reading
Recirculating-to-discharge Air Temperature Table
Ambient Air Temperature-to-operating Pressure Table
Vehicle condition Indoors or in the shade (in a well-ventilated place)
Doors Closed
Door windows Open
Hood Open
TEMP. Max. COLD
Mode control dial
(Ventilation) set
Intake switch
(Recirculation) set
Fan (blower) speedMax. speed set
Engine speed Idle speed
Operate the air conditioning system for 10 minutes before taking measurements.
Inside air (Recirculating air) at blower assembly inlet
Discharge air temperature at center ventilator
°C (°F) Relative humidity
%Air temperature
°C (°F)
50 - 6020 (68) 6.1 - 8.7 (43 - 48)
25 (77) 8.5 - 11.5 (47 - 53)
60 - 7020 (68) 8.7 - 11.1 (48 - 52)
25 (77) 11.5 - 14.5 (53 - 58)
Ambient air
High-pressure (Discharge side)
kPa (kg/cm
2 , psi)Low-pressure (Suction side)
kPa (kg/cm2 , psi) Relative humidity
%Air temperature
°C (°F)
50 - 7020 (68)850 - 1,050
(8.67 - 10.71, 123.3 - 152.3)180 - 230
(1.84 - 2.35, 26.1 - 33.4)
25 (77)1,020 - 1,260
(10.40 - 12.85, 147.9 - 182.7)190 - 240
(1.94 - 2.45, 27.6 - 34.8)
30 (86)1,150 - 1,410
(11.73 - 14.38, 166.8 - 204.5)210 - 250
(2.14 - 2.55, 30.5 - 36.3)
35 (95)1,240 - 1,510
(12.65 - 15.40, 179.8 - 219.0)220 - 270
(2.24 - 2.75, 31.9 - 39.2)

ATC-86
TROUBLE DIAGNOSIS
Revision: 2006 November2007 350Z
TROUBLE DIAGNOSIS FOR UNUSUAL PRESSURE
Whenever system’s high and/or low side pressure(s) is/are unusual, diagnose using a manifold gauge. The
marker above the gauge scale in the following tables indicates the standard (usual) pressure range. Since the
standard (usual) pressure, however, differs from vehicle to vehicle, refer to above table (Ambient air tempera-
ture-to-operating pressure table).
Both High- and Low-pressure Sides are Too High
High-pressure Side is Too High and Low-pressure Side is Too Low
Gauge indication Refrigerant cycle Probable cause Corrective action
Both high- and low-pressure sides
are too high.The pressure returns to normal
soon after water is splashed on
condenser.Excessive refrigerant charge
in refrigeration cycle.Reduce refrigerant until speci-
fied pressure is obtained.
Air suction by cooling fan is
insufficient.Insufficient condenser cooling
performance.
↓
1. Condenser fins are clogged.
2. Improper fan rotation of
cooling fan.

Clean condenser.

Check and repair cooling
fan as necessary.

Low-pressure pipe is not
cold.

When compressor is
stopped high-pressure value
quickly drops by approxi-
mately 196 kPa (2 kg/cm
2 ,
28 psi). It then decreases
gradually thereafter.Poor heat exchange in con-
denser
(After compressor operation
stops, high-pressure
decreases too slowly.).
↓
Air in refrigeration cycle.Evacuate repeatedly and
recharge system.
Engine tends to overheat.Engine cooling systems mal-
function.Check and repair each engine
cooling system.

An area of the low-pressure
pipe is colder than areas
near the evaporator outlet.

Low-pressure pipe is some-
times covered with frost.

Excessive liquid refrigerant
on low-pressure side.

Excessive refrigerant dis-
charge flow.

Expansion valve is open a
little compared with the
specification.
↓
Improper expansion valve
adjustment.Replace expansion valve.
AC359A
Gauge indication Refrigerant cycle Probable cause Corrective action
High-pressure side is too high and
low-pressure side is too low.
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.

Check and repair or replace
malfunctioning parts.

Check lubricant for contami-
nation.
AC360A

TROUBLE DIAGNOSIS
ATC-87
C
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AT C
Revision: 2006 November2007 350Z
High-pressure Side is Too Low and Low-pressure Side is Too High
Both High- and Low-pressure Sides are Too Low
Gauge indication Refrigerant cycle Probable cause Corrective action
High-pressure side is too low and
low-pressure side is too high.High- and low-pressure sides
become equal soon after com-
pressor operation stops.Compressor pressure opera-
tion is improper.
↓
Damaged inside compressor
packings.Replace compressor.
No temperature difference
between high- and low-pres-
sure sides.Compressor pressure opera-
tion is improper.
↓
Damaged inside compressor
packings.Replace compressor.
AC356A
Gauge indication Refrigerant cycle Probable cause Corrective action
Both high- and low-pressure sides
are too low.

There is a big temperature
difference between liquid
tank outlet and inlet. Outlet
temperature is extremely
low.

Liquid tank inlet and expan-
sion valve are frosted.Liquid tank inside is slightly
clogged.

Replace liquid tank.

Check lubricant for contami-
nation.

Temperature of expansion
valve inlet is extremely low
as compared with areas
near liquid tank.

Expansion valve inlet is
frosted.

Temperature difference
occurs somewhere in high-
pressure side.High-pressure pipe located
between liquid tank and
expansion valve is clogged.

Check and repair malfunc-
tioning parts.

Check lubricant for contami-
nation.
Expansion valve and liquid
tank are warm or slightly cool
when touched.Low refrigerant charge.
↓
Leaking fittings or compo-
nents.Check refrigerant for leaks.
Refer to ATC-138, "
Checking
for Refrigerant Leaks" .
There is a big temperature dif-
ference between expansion
valve inlet and outlet while the
valve itself is frosted.Expansion valve closes a little
compared with the specifica-
tion.
↓
1. Improper expansion valve
adjustment.
2. Malfunctioning expansion
valve.
3. Outlet and inlet may be
clogged.

Remove foreign particles by
using compressed air.

Replace expansion valve.

Check lubricant for contami-
nation.
An area of the low-pressure
pipe is colder than areas near
the evaporator outlet.Low-pressure pipe is clogged
or crushed.

Check and repair malfunc-
tioning parts.

Check lubricant for contami-
nation.
Air flow volume is not enough
or is too low.Evaporator is frozen.

Check intake sensor circuit.
Refer to ATC-100, "
Intake
Sensor Circuit" .

Replace compressor.

Repair evaporator fins.

Replace evaporator.

Refer to AT C - 6 9 , "Blower
Motor Circuit" .
AC353A

ATC-88
TROUBLE DIAGNOSIS
Revision: 2006 November2007 350Z
Low-pressure Side Sometimes Becomes Negative
Low-pressure Side Becomes Negative
Gauge indication Refrigerant cycle Probable cause Corrective action
Low-pressure side sometimes
becomes negative.

Air conditioning system
does not function and does
not cyclically cool the com-
partment air.

The system constantly func-
tions for a certain period of
time after compressor 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.

Drain water from refrigerant
or replace refrigerant.

Replace liquid tank.
AC354A
Gauge indication Refrigerant cycle Probable cause Corrective action
Low-pressure side becomes nega-
tive.
Liquid tank or front/rear side of
expansion valve’s pipe is
frosted or wet with dew.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 malfunction is caused by
water or foreign particles.

If water is the cause, initially
cooling is okay. Then the
water freezes causing a
blockage. Drain water from
refrigerant or replace refrig-
erant.

If due to foreign particles,
remove expansion valve
and remove the particles
with dry and compressed air
(not shop air).

If either of the above meth-
ods cannot correct the mal-
function, replace expansion
valve.

Replace liquid tank.

Check lubricant for contami-
nation.
AC362A