Toyota Tundra. Manual — part 2432

Fig. 147: Checking Refrigerant Pressure
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

2. The A/C system periodically changes between normal and improper function due to moisture

in the refrigerant system.

Fig. 148: Checking Refrigerant Pressure - Moisture In Refrigerant System
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

SYMPTOM DIAGNOSIS CHART

3. The A/C system does not function effectively due to insufficient cooling.

Symptoms

Probable Cause

Diagnosis

Corrective Actions

During operation,
pressure on low
pressure side
cycles between
normal and
vacuum

Moisture in refrigeration
system freezes at
expansion valve orifice,
causing temporary stop
of cycle. However,
when melted, normal
state is restored.



Drier is overly
saturated



Moisture in
refrigeration system
freezes at expansion
valve orifice and
blocks refrigerant
circulation

1. Replace cooler

drier

2. Remove

moisture from
cycle by
repeatedly
evacuating air

3. Supply

appropriate
volume of new
refrigerant

2009 Toyota Tundra

2009 HVAC Air Conditioning - Tundra

Fig. 149: Checking Refrigerant Pressure - Insufficient Cooling
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

SYMPTOM DIAGNOSIS CHART

4. The A/C system does not function effectively due to poor circulation of the refrigerant.

Fig. 150: Checking Refrigerant Pressure - Poor Circulation Of Refrigerant
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

SYMPTOM DIAGNOSIS CHART

Symptoms

Probable

Cause

Diagnosis

Corrective Actions



Pressure low on
both low and
high pressure
sides



Cooling
performance
insufficient

Gas leakage
from
refrigeration
system



Insufficient
refrigerant



Refrigerant
leakage

1. Check for gas leakage and

repair if necessary

2. Supply appropriate

volume of new refrigerant

3. If indicated pressure value

close to 0 when connected
to gauge, create vacuum
after inspecting and
repairing the location of
leakage

Symptoms

Probable Cause

Diagnosis

Corrective

Actions



Pressure low on both low
and high pressure sides



Frost exists on piping from
condenser to A/C unit

Refrigerant flow obstructed
by dirt in condenser

Condenser
clogged

Replace
condenser

2009 Toyota Tundra

2009 HVAC Air Conditioning - Tundra

5. The A/C system does not function or functions intermittently because the refrigerant does not

circulate.

Fig. 151: Checking Refrigerant Pressure - Refrigerant Does Not Circulate
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

SYMPTOM DIAGNOSIS CHART

6. The A/C system does not function effectively due to overcharged refrigerant or insufficient

cooling of the condenser.

Fig. 152: Checking Refrigerant Pressure - Overcharged Refrigerant Or Insufficient

Symptoms

Probable Cause

Diagnosis

Corrective Actions



Vacuum indicated on
low pressure side, and
extremely low
pressure indicated on
high pressure side



Frost or condensation
seen on piping on both
sides of condenser or
expansion valve



Refrigerant flow
obstructed by
moisture or dirt in
refrigeration
system



Refrigerant flow
obstructed by gas
leakage from
expansion valve

Refrigerant
does not
circulate

1. Check expansion

valve refrigerant

2. Clean expansion

valve by
blowing air

3. Replace

condenser

4. Evacuate air and

charge
appropriate
volume of new
refrigerant

5. For gas leakage

from expansion
valve, replace
expansion valve

2009 Toyota Tundra

2009 HVAC Air Conditioning - Tundra

Cooling Of Condenser
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

SYMPTOM DIAGNOSIS CHART

7. The A/C system does not function due to air in the refrigeration system.

Fig. 153: Checking Refrigerant Pressure - Air In Refrigeration System
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

HINT:

These gauge indications occur when the refrigeration system opens and the refrigerant is
charged without vacuum purging

SYMPTOM DIAGNOSIS CHART

Symptoms

Probable Cause

Diagnosis

Corrective Actions

Pressure
extremely high
on both low and
high-pressure
sides



Excessive
refrigerant



Cooling
performance of
condenser
insufficient



Condenser is
dirty



Condenser fan
motor is
malfunctioning



Excessive
refrigerant

1. Clean condenser

2. Check condenser fan

motor operation

3. If 1 and 2 normal,

check the amount of
refrigerant and
supply appropriate
volume of
refrigerant

CAUTION: The low-pressure piping may be very hot and cause

serious burns.

Symptoms

Probable

Cause

Diagnosis

Corrective Actions



Pressure extremely
high on both low and
high-pressure sides



Low-pressure piping

Air in
refrigeration
system



Air in
refrigeration
system



Vacuum
purging

1. Check if

compressor oil is
dirty or
insufficient

2. Evacuate air and

2009 Toyota Tundra

2009 HVAC Air Conditioning - Tundra