Nissan Titan. Instruction — part 417

INSUFFICIENT COOLING

HAC-173

< SYMPTOM DIAGNOSIS >

[MANUAL A/C (TYPE 1)]

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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 liquid tank.
• Check oil for contamination.

• 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 liquid tank and expan-
sion valve is clogged.

• Check and repair malfunc-

tioning parts.

• Check oil for contamination.

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

Low refrigerant charge.
↓
Leaking fittings or compo-
nents.

Check refrigerant system for
leaks. Refer to

HA-24, "Check-

ing of Refrigerant Leaks"

or

HA-26, "Checking of Refriger-
ant 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.

• Check oil for contamination.

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 oil for contamination.

Air flow volume is too low.

Evaporator is frozen.

• Check intake sensor circuit.

Refer to

HAC-147, "Intake

Sensor Diagnosis Proce-
dure"

.

• Repair evaporator fins.
• Replace evaporator.
• Refer to

HAC-131, "Front

Blower Motor Component
Function Check"

.

AC353A

HAC-174

< SYMPTOM DIAGNOSIS >

[MANUAL A/C (TYPE 1)]

INSUFFICIENT COOLING

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 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 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 malfunction 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 mal-
function, replace expansion
valve.

• Replace liquid tank.
• Check oil for contamination.

AC362A

INSUFFICIENT HEATING

HAC-175

< SYMPTOM DIAGNOSIS >

[MANUAL A/C (TYPE 1)]

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INSUFFICIENT HEATING

Component Function Check

INFOID:0000000009882555

SYMPTOM: Insufficient heating

INSPECTION FLOW

1.

CONFIRM SYMPTOM BY PERFORMING OPERATIONAL CHECK - TEMPERATURE INCREASE

1. Turn the blower control dial to low speed.

2. Turn the temperature control dial clockwise to maximum heat

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

YES

>> GO TO 2.

NO

>> Perform complete system operational check. Refer to

HAC-99, "Operational Check"

.

2.

CHECK FOR SERVICE BULLETINS

Check for any service bulletins.

>> If equipped with NAVI, GO TO 3.

>> If not equipped with NAVI, GO TO 4.

3.

PERFORM SELF-DIAGNOSIS

Perform self-diagnosis. Refer to

HAC-114, "Front Air Control Self-Diagnosis"

.

Is the inspection results normal?

YES

>> GO TO 4.

NO

>> Refer to

HAC-166, "Symptom Matrix Chart"

.

4.

CHECK ENGINE COOLING SYSTEM

1. Check for proper engine coolant level. Refer to

CO-10, "Inspection"

.

2. Check hoses for leaks or kinks.

3. Check radiator cap. Refer to

CO-10, "Inspection"

.

4. Check for air in cooling system.

>> GO TO 5.

5.

CHECK AIR MIX DOOR OPERATION

Check the operation of the air mix door.
Is the inspection result normal?

YES

>> GO TO 6.

NO

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

HAC-120, "Air Mix Door Motor Component Function

Check"

.

6.

CHECK AIR DUCTS

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

YES

>> GO TO 7.

NO

>> Repair all disconnected or leaking air ducts.

7.

CHECK HEATER HOSE TEMPERATURES

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

2. Touch both the inlet and outlet heater hoses. The inlet hose should be hot and the outlet hose should be

warm.

Is the inspection result normal?

YES

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

NO

>> • Inlet hose cold: GO TO 11.

• Both hoses warm: GO TO 9.

HAC-176

< SYMPTOM DIAGNOSIS >

[MANUAL A/C (TYPE 1)]

INSUFFICIENT HEATING

8.

CHECK ENGINE COOLANT SYSTEM

Check engine control temperature sensor. Refer to

EC-191, "Component Inspection"

.

Is the inspection result normal?

YES

>> System OK.

NO

>> Repair or replace as necessary. Retest.

9.

CHECK HEATER HOSES

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

YES

>> System OK.

NO

>> 1. Back flush heater core.

2. Drain the water from the system.

3. Refill system with new engine coolant. Refer to

CO-11, "Changing Engine Coolant"

.

4. GO TO 10 to retest.

10.

CHECK HEATER HOSE TEMPERATURES

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

2. Touch both the inlet and outlet heater hoses. The inlet hose should be hot and the outlet hose should be

warm.

Is the inspection result normal?

YES

>> System OK.

NO

>> Replace heater core. Refer to

VTL-15, "Removal and Installation"

.

11.

CHECK WATER VALVE

Check the operation of the water valve. Refer to

HAC-142, "Water Valve Diagnosis Procedure"

.

Is the inspection result normal?

YES

>> System OK.

NO

>> Replace water valve.