Lexus ES300 (1997 year). Manual - part 31

I01450

Condition: Insufficient cooling

I01393

Condition : Does not cool

–

AIR CONDITIONING

AIR CONDITIONING SYSTEM

AC–7

1564

1997 LEXUS ES300   (RM511U)

(8)

Expansion valve improperly

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)

Defective compression compressor

Symptom seen in 

refrigeration system

Probable cause

Diagnosis

Remedy



 Pressure too high on low and

high pressure sides



 Pressure too low on high pres-

sure side

Internal leak in compressor



 Compression defective



 Valve leaking or broken sliding

parts

Repair or replace compressor

N14519

Drain Hose

AC–8

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AIR CONDITIONING

AIR CONDITIONING SYSTEM

1565

1997 LEXUS ES300   (RM511U)

3.

INSPECT IDLE–UP SPEED

(a)

Warm up engine

(b)

Inspect idle–up speed when the these conditions are es-
tablished.
Test conditions:



Blower speed control set at ”HI”



Temperature control set at ”MAX COOL”



A/C switch ON



Put gear shift in neutral

Magnetic clutch condition

Idle speed

Magnetic clutch not engaged

700 

±

 50 rpm

Magnetic clutch engaged

700 

±

 50 rpm

If idle speed is not as specified, check IAC valve and air intake
system.

4.

INSPECT FOR LEAKAGE OF REFRIGERANT

(a)

Perform under these conditions:



Stop engine



Secure good ventilation (If not, the gas leak detec-
tor may react to volatile gases which are not refrig-
erant, such as evaporated gasoline or exhaust
gas.)



Repeat the test 2 or 3 times



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

2

, 57 – 85 psi)

(b)

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

HINT:



After the blower motor is stopped, leave the A/C unit for
more than 15 minutes.



Expose the gas leak detector sensor the under the drain
hose.



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

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

If gas leak is not detected through the drain hose, remove
the blower linear controller from the A/C unit. Then insert
the gas leak detector sensor into the unit and perform the
test.

N14517

Gas Leak
Detector

Pressure
Switch

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AIR CONDITIONING

AIR CONDITIONING SYSTEM

AC–9

1566

1997 LEXUS ES300   (RM511U)

(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.

HINT:
Make sure that there is no dirt on joints.

AC09E–01

N13795

Quick Disconnect
 adapter

Charging Hose

Service Valve

N13794

Vacuum Pump

Vacuum Pump Adapter

N13791

Manifold 
Gauge Set

High Pressure 
Service Valve

Low Pressure 
Service Valve

Vacuum Pump 
Adapter

AC–10

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AIR CONDITIONING

AIR CONDITIONING SYSTEM

1567

1997 LEXUS ES300   (RM511U)

EVACUATING

1.

CONNECT QUICK DISCONNECT ADAPTER TO
CHARGING HOSES

2.

REMOVE CAPS FROM SERVICE VALVES ON RE-
FRIGERANT LINES

3.

SET ON MANIFOLD GAUGE SET

(a)

Close both hand valves of manifold gauge set.

(b)

Connect the quick disconnect adapter to the service
valves.

4.

EVACUATE AIR FROM REFRIGERATION SYSTEM

(a)

Connect the vacuum pump adapter to the vacuum pump.

(b)

Connect the center hose of the manifold gauge set to the
vacuum pump adapter.

(c)

Open both the high and low hand valves and run the vacu-
um pump.

(d)

After 10 minutes or more, check that the low pressure
gauge indicates 750 mmHg (30 in.Hg) or more.

HINT:
If the reading is not 750 mmHg (30 in.Hg) or more, close both
hand valves of manifold gauge set and stop the vacuum pump.
Check the system for leaks and repair as necessary.
(e)

Close both the high and low hand valves and stop the vac-
uum pump.

(f)

Leave the system in this condition for 5 minutes or more
and check that there is no gauge indicator.