Lexus ES300 (1997 year). Service manual — part 438

I00314

R/F Switch

AUTO Switch

I00339

4 times

1 sec.

1 sec.

ON

OFF

Blinking Pattern

I00314

Code Display

I00314

Front DEF Switch

I00349

ECU–B

Engine Room J/B

–

DIAGNOSTICS

AIR CONDITIONING SYSTEM

DI–529

681

1997 LEXUS ES300 (RM511U)

3.

INDICATOR CHECK

(a)

Turn the ignition switch on while pressing the air condi-
tioning control AUTO switch and R/F switch simulta-
neously.

(b)

Check that the indicators light up and go off at second in-
tervals 4 times in succession.

HINT:

After the indicator check is completed, the system enters
the DTC begins automatically.

Press the OFF switch when desiring to cancel the check
mode.

4.

DTC CHECK (SENSOR CHECK)

(a)

Perform an indicator check. After the indicator check is
completed, the system enters the DTC check mode auto-
matically.

(b)

Read the code displayed on the panel. Refer to the list of
codes on page

DI–531

when reading the codes. (Trouble

code are output at the temperature display.)

(c)

If the slower display is desired, press the front DEF switch
and change it to stepped operation. Each time the front
DEF switch is pressed, the display changes by 1 step.

5.

CLEARING DTC

(a)

Pull out the ECU–B fuse in engine room J/B for 10 sec.
or longer to clear the DTC memory.

(b)

After reinserting the fuse, check that the normal code is
output.

I00314

R/F Switch

OFF Switch

DI–530

–

DIAGNOSTICS

AIR CONDITIONING SYSTEM

682

1997 LEXUS ES300 (RM511U)

6.

ACTUATOR CHECK

(a)

After entering the DTC check mode (Sensor Check
Mode) press the R/F switch.

(b)

Since each damper, motor and relay automatically oper-
ates at 1 second intervals beginning in order from 10 in
the temperature display, check the temperature and air
flow visually and by hand.
If the slower display is desired, press the DEF switch and
change it to step operation. Each time the DEF switch is
pressed, the display changes by 1 step.

HINT:

Code are displayed in order from the smaller to the larger
numbers.

To cancel the check mode, press the OFF switch.

Step

No

Display

Code

Conditions

No.

Code

Blower Motor

Air Flow Vent

Air Inlet Damper

Magnetic Clutch

Air Mix Damper

1

0

OFF

FACE

FRESH

OFF

Cool side

(0 % open)

2

1

1

FACE

FRESH

OFF

Cool side

(0 % open)

3

2

3

FACE

FRESH

ON

Cool side

(0 % open)

4

3

3

FACE

FRS/REC

ON

Cool side

(0 % open)

5

4

3

FACE

RECIRC

ON

Cool/Hot

(50 % open)

6

5

3

BI–LEVEL

RECIRC

ON

Cool/Hot

(50 % open)

7

6

3

FOOT

RECIRC

ON

Hot side

(100 % open)

8

7

3

FOOT

RECIRC

ON

Hot side

(100 % open)

9

8

3

FOOT/DEF

RECIRC

ON

Hot side

(100 % open)

10

9

5

DEF

RECIRC

ON

Hot side

(100 % open)

DI0D5–01

–

DIAGNOSTICS

AIR CONDITIONING SYSTEM

DI–531

683

1997 LEXUS ES300 (RM511U)

DIAGNOSTIC TROUBLE CODE CHART

If malfunction code is displayed during the DTC check (sensor check), check the circuit listed for that code
in the table below (Proceed to the page given for that circuit).

DTC No.

(See Page)

Detection Item

Trouble Area

Memory

00

Normal

–

–

11*

1

(

DI–537

)

Room temperature sensor circuit

Room temp. Sensor

ECU

Harness or connector between room temp. sensor and A/C

control assembly

(8.5 min. or more)

12*

2

(

DI–540

)

Ambient temperature sensor circuit

Ambient temp. Sensor

Harness or connector between ambient temp. sensor and

ECU

ECU

(8.5 min. or more)

13

(

DI–543

)

Evaporator temperature sensor circuit

Evaporator temp. Sensor

Harness or connector between evaporator temp. sensor and

ECU

ECU

(8.5 min. or more)

14

(

DI–546

)

Engine coolant temperature sensor cir-

cuit

Engine coolant temp. sensor

Harness or connector between engine coolant temp. sensor

and ECU

Harness or connector between ECM and A/C ECU

ECU

–

21*

3

(

DI 549

)

Solar sensor circuit (short)

Solar sensor

Harness or connector between solar sensor and ECU

(8.5 min. or more)

(

DI–549

)

Solar sensor circuit (open)

ECU

–

22*

4

(

DI–552

)

Compressor lock sensor circuit

Compressor Drive Belt

Compressor lock sensor

Compressor

Harness or connector between compressor and ECU, com-

pressor lock sensor

ECU

–

23

(

DI–554

)

Pressure sensor circuit

Pressure switch

Harness or connector between pressure switch and ECU

Refrigerant pipe line

ECU

–

31

(

DI–557

)

Air mix damper position sensor circuit

Air mix damper position sensor

ECU

Harness or connector between air mix damper position sen-

sor and ECU

(1 min. or more)

32

(

DI–560

)

Air inlet damper position sensor circuit

Air inlet damper position sensor

ECU

Harness or connector between air inlet damper position

sensor and ECU

(1 min. or more)

41

(

DI–557

DI–563

)

Air mix control servomotor

Air mix control servomotor

Air mix damper position sensor

Harness or connector between air mix damper servomotor

and ECU

ECU

(15 sec.)

42

(

DI–560

DI–566

)

Air inlet control servomotor

Air inlet control servomotor

Air inlet damper position sensor

Harness or connector between air inlet damper, servomotor

and ECU

ECU

(15 sec.)

DI–532

–

DIAGNOSTICS

AIR CONDITIONING SYSTEM

684

1997 LEXUS ES300 (RM511U)

HINT:

*

1:

If the room temp. is approx. –18.6

°

C (–3.7

°

F) or lower, trouble code 11 may be output even though

the system is normal.

*

2

: If the ambient temp. is approx. –52.9

°

C (–61.4

°

F) or lower, a malfunction code may be output even

though the system is normal.

*

3

: If the check is being performed in a dark place, DTC 21 (solar sensor circuit abnormal) could be

displayed.

*

4

:Compressor lock (DTC22) is indicated only for a current occurring malfunction (See page

DI–552

).

To confirm DTC 22, perform the following steps.
(1)

With the engine ON, enter the DTC check mode.

(2)

Press the F/R switch to enter actuator check mode, and set the operation to Step No.3.

(3)

Press the AUTO switch to return to DTC check mode.

(4)

The DTC is displayed after approx. 3 secs..

*

5

: The ECU memorizes the DTC of the respective malfunction it has occurred for the period of the time

indicated in the brackets.