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Nissan Altima L32. Manual - part 829

HAC-90

< SYMPTOM DIAGNOSIS >

[AUTOMATIC AIR CONDITIONER]

INSUFFICIENT COOLING

Both High- and Low-pressure Sides are Too Low

Low-pressure Side Sometimes Becomes Negative

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 be-
tween high and low-pressure
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 desiccant assem-

bly.

• Check lubricant for contami-

nation.

• Temperature of expansion

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

• Expansion valve inlet may

be frosted.

• Temperature difference oc-

curs somewhere in high-
pressure side

High-pressure pipe located be-
tween receiver drier and ex-
pansion valve is clogged.

• Check and repair malfunc-

tioning parts.

• Check lubricant for contami-

nation.

Expansion valve and liquid
tank are warm or only cool
when touched.

Low refrigerant charge
↓
Leaking fittings or components

Check refrigerant for leaks.
Refer to

HA-25, "Checking of

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

Malfunctioning thermal
valve

Outlet and inlet may be
clogged.

• Remove foreign particles by

using compressed air.

• 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 thermo control amp.

and intake sensor operation.

• Replace compressor.

AC353A

INSUFFICIENT COOLING

HAC-91

< SYMPTOM DIAGNOSIS >

[AUTOMATIC AIR CONDITIONER]

HAC

Low-pressure Side Becomes Negative

Gauge indication

Refrigerant cycle

Probable cause

Corrective action

Low-pressure side sometimes be-
comes negative.

• Air conditioning system does

not function and does not cy-
clically cool the compart-
ment air.

• The system constantly func-

tions for a certain period of
time after compressor is
stopped and restarted.

Refrigerant does not discharge
cyclically.
↓
Moisture is frozen at expan-
sion valve outlet and inlet.
↓
Water is mixed with refrigerant.

• Drain water from refrigerant

or replace refrigerant.

• Replace desiccant assem-

bly.

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 frost-
ed 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.
• If water is the cause, initially

cooling is okay. Then the wa-
ter freezes causing a block-
age. Drain water from
refrigerant or replace refrig-
erant.

• If due to foreign particles, re-

move expansion valve and
remove the particles with dry
and compressed air (not
shop air).

• If either of the above meth-

ods cannot correct the prob-
lem, replace expansion
valve.

• Replace desiccant assem-

bly.

• Check lubricant for contami-

nation.

AC362A

HAC-92

< SYMPTOM DIAGNOSIS >

[AUTOMATIC AIR CONDITIONER]

INSUFFICIENT HEATING

INSUFFICIENT HEATING

Component Function Check

INFOID:0000000004498239

SYMPTOM: Insufficient heating

INSPECTION FLOW

SYMPTOM: Insufficient heating

CONFIRM SYMPTOM BY PERFORMING OPERATION CHECK - TEMPERATURE INCREASE

1. Press the AUTO switch.

2. Turn temperature control dial (LH) clockwise until 32

°C (90°F) is displayed.

3. Check for hot air at discharge air outlets.
Can a symptom be duplicated?

YES

>> GO TO 3

>> GO TO 2

CHECK FOR ANY SYMPTOMS

Perform a complete operational check and check for any symptoms. Refer to

HAC-5, "Description and Condi-

tions"

Does another symptom exist?

YES

>> Refer to

HAC-83, "Symptom Matrix Chart"

>> System OK.

CHECK FOR SERVICE BULLETINS

Check for any service bulletins.

>> GO TO 4

CHECK ENGINE COOLING SYSEM

1. Check for proper engine coolant level. Refer to

CO-11, "System Inspection"

(QR25DE) or

CO-34, "System

Inspection"

(VQ35DE).

2. Check hoses for leaks or kinks.

3. Check radiator cap. Refer to

CO-11, "System Inspection"

(QR25DE) or

CO-34, "System Inspection"

(VQ35DE).

4. Check for air in cooling system.

>> GO TO 5

CHECK AIR MIX DOOR MOTOR OPERATION

Check and verify air mix door mechanism for smooth operation.
Does air mix door operate correctly?

YES

>> GO TO 6

>> Check the air mix door motor circuit. Refer to

HAC-35, "Diagnosis Procedure"

CHECK AIR DUCTS

Check for disconnected or leaking air ducts.
Is the inspection result normal?

YES

>> GO TO 7

>> Repair all disconnected or leaking air ducts.

CHECK HEATER HOSE TEMPERATURES

1. Start engine and warm it up to normal operating temperature.

2. Touch both the inlet and outlet heater hoses.
Is the inspection result normal?

YES

>> Hot inlet hose and a warm outlet hose: GO TO 8

INSUFFICIENT HEATING

HAC-93

< SYMPTOM DIAGNOSIS >

[AUTOMATIC AIR CONDITIONER]

HAC

>> Both hoses warm: GO TO 9

CHECK ENGINE COOLANT SYSTEM

Check thermostat operation. Refer to

CO-21, "Removal and Installation"

(QR25DE) or

CO-46, "Removal and

Installation"

(VQ35DE).

Is the inspection result normal?

YES

>> System OK.

>> Repair or replace as necessary.

CHECK HEATER HOSES

Check heater hoses for proper installation.
Is the inspection result normal?

YES

>> System OK.

>> 1. Back flush heater core.

2. Drain the water from the system.

3. Refill system with new engine coolant. Refer to

CO-12, "Changing Engine Coolant"

(QR25DE) or

CO-35, "Changing Engine Coolant"

(VQ35DE).

4. To retest GO TO 10

10.

CHECK HEATER HOSE TEMPERATURES

1. Start engine and warm up to normal operating temperature.

2. Touch both the inlet and outlet heater hoses.
Is the inspection result normal?

YES

>> System OK.

>> Replace heater core Refer to

VTL-22, "Removal and Installation"

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