Toyota Sequoia (2005). Manual — part 936

I01389

Condition: Insufficient cooling

I01449

Condition: Does not cool (Cools from time to time in some cases)

AC–6

–

AIR CONDITIONING

AIR CONDITIONING SYSTEM

3733

(4)

Poor circulation of refrigerant

Symptom seen in

refrigeration system

Probable cause

Diagnosis

Remedy

Pressure low on both low and

high pressure sides

Frost on tube from receiver to

unit

Refrigerant flow obstructed by dirt

in receiver

Receiver clogged

Replace receiver

(5)

Refrigerant does not circulate

Symptom seen in

refrigeration system

Probable cause

Diagnosis

Remedy

Vacuum indicated on low pres-

sure side, very low pressure indi-

cated on high pressure side

Frost or dew seen on piping on

both sides of receiver/ drier or ex-

pansion valve

Refrigerant flow obstructed by

moisture or dirt in refrigeration sys-

tem

Refrigerant flow obstructed by

gas leakage from expansion valve

Refrigerant does not circulate

(1) Check expansion valve

(2) Clean out dirt in expansion

valve by blowing with air

(3) Replace receiver

(4) Evacuate air and charge new

refrigerant to proper amount

(5) For gas leakage from expan-

sion valve, replace expansion

valve

I22614

Condition: Insufficient cooling

Single A/C:

Dual A/C:

I22614

Condition: Insufficient cooling

Single A/C:

Dual A/C:

NOTE: These indications
are shown when the refrig-
eration system has been
opened and the refrigerant
has been charged without
vacuum purging.

–

AIR CONDITIONING

AIR CONDITIONING SYSTEM

AC–7

3734

(6)

Refrigerant overcharged or insufficient cooling of
condenser

Symptom seen in

refrigeration system

Probable cause

Diagnosis

Remedy

Pressure too high on both low

and high pressure sides

No air bubbles seen through the

sight glass even when the engine

rpm is lowered

Unable to develop sufficient per-

formance due to excessive refrig-

erant

Insufficient cooling of condenser

Excessive refrigerant in

cycle

→

refrigerant overcharged

Condenser cooling

insufficient

→

condenser fins

clogged or cooling fan faulty

(1) Clean condenser

(2) Check cooling fan with fluid

coupling operation

(3) If (1) and (2) are in normal

state, check amount of refrigerant

and charge proper amount of re-

frigerant

(7)

Air present in refrigeration system

Symptom seen in

refrigeration system

Probable cause

Diagnosis

Remedy

Pressure too high on both low

and high pressure sides

The low pressure piping hot to

the touch

Bubbles seen in sight glass

Air in refrigeration system

Air present in refrigeration sys-

tem

Insufficient vacuum purging

(1) Check compressor oil to see if

it is dirty or insufficient

(2) Evacuate air and charge new

refrigerant

I22614

Condition: Insufficient cooling

Single A/C:

Dual A/C:

I22615

Condition: Does not cool

Single A/C:

Dual A/C:

AC–8

–

AIR CONDITIONING

AIR CONDITIONING SYSTEM

3735

(8)

Expansion valve malfunction

Symptom seen in

refrigeration system

Probable cause

Diagnosis

Remedy

Pressure too high on both low

and high pressure sides

Frost or large amount of dew on

piping on low pressure side

Trouble in expansion valve

Excessive refrigerant in low

pressure piping

Expansion valve opened too

wide

Check expansion valve

Replace if defective

(9)

Insufficient compressor compression

Symptom seen in

refrigeration system

Probable cause

Diagnosis

Remedy

Pressure too high on both low

and high pressure sides

Pressure too low on high pres-

sure side

Internal leak in compressor

Low compression

Leak from valve or broken sliding

parts

Repair or replace compressor

–

AIR CONDITIONING

AIR CONDITIONING SYSTEM

AC–9

3736

3.

INSPECT IDLE–UP SPEED

(a)

Warm up the engine.

(b)

Inspect idle–up speed when the following conditions are
established.

Warm up engine

Blower speed control switch at ”HI” position

A/C switch ON

Temperature control dial at ”COOL” position

Magnetic clutch condition

Idle–up speed

Magnetic clutch not engaged

700

±

50 rpm

Magnetic clutch engaged

780

±

50 rpm

If idle speed is not as specified, check the Idle control system.
4.

INSPECT FOR LEAKAGE OF REFRIGERANT

(a)

Perform under the following conditions:

Stop the engine.

Secure good ventilation (If not, the gas leak detec-
tor may react to volatile gases witch are not refriger-
ant, such as evaporated gasoline and exhaust gas.)

Repeat the test 2 or 3 times.

Make sure that there is some refrigerant remaining
in the refrigeration system.
When the compressor is OFF: approx. 392 to 588
kPa (4 to 6 kgf/ cm

2

, 57 to 85 psi)

(b)

Bring the gas leak detector close to the drain hose before
performing the test.

HINT:

After the blower motor stopped, leave the cooling unit for
more than 15 minutes.

Bring the gas leak detector sensor under the drain hose.

When bringing the gas leak detector close to the drain
hose, make sure that the gas leak detector does not react
to the volatile gases.

If such reaction is unavoidable, the vehicle must be lifted up.
(c)

If gas leak is not detected on the drain hose, remove the
blower motor linear controller from the cooling unit. Then
insert the gas leak detector sensor into the unit and per-
form the test.

(d)

Disconnect the connector and leave the pressure switch
for approx. 20 minutes. Then bring the gas leak detector
close to the pressure switch and perform the test.

(e)

Bring the gas leak detector close to the refrigerant lines
and perform the test.