Lexus ES300 (1997 year). Manual — part 446

BE3840

I00331

I00338

ON

SG(–)

TPI(+)

–

DIAGNOSTICS

AIR CONDITIONING SYSTEM

DI–561

713

1997 LEXUS ES300 (RM511U)

INSPECTION PROCEDURE

1

Check voltage between terminals TPI and SG of A/C control assembly connector.

PREPARATION:
(a)

Remove A/C control assembly with connectors still con-
nected (See page

BO–79

).

(b)

Turn ignition switch ON.

CHECK:
Press REC/FRS switch to change air inlet between fresh and
recirculation air, and measure voltage between terminals TPI
and SG of A/C control assembly when the air inlet servomotor
operates.
OK:

REC/FRS Switch

Voltage

REC

3.5 – 4.5 V

FRS

0.5 – 1.8 V

HINT:
As the air inlet control servomotor is moved from REC side to
FRS side, the voltage decreases gradually without interruption.

NG

Go to step 2.

OK

Proceed to next circuit inspection shown on matrix chart (See page

DI–535

). However, if DTC 32

or 42 is displayed, check and replace A/C control assembly.

I00361

FRS

REC

1

2

3

4

5

6

7

DI–562

–

DIAGNOSTICS

AIR CONDITIONING SYSTEM

714

1997 LEXUS ES300 (RM511U)

2

Check air inlet damper position sensor.

PREPARATION:
(a)

Remove air inlet control servomotor (See page

AC–70

).

(b)

Disconnect air inlet control servomotor connector.

CHECK:
Measure resistance between terminals 4 and 5 of air inlet con-
trol servomotor connector.
OK:

Resistance: 4.2 – 7.8 k

Ω

CHECK:
While operating air inlet control servomotor as in the procedure
on page , measure resistance between terminals 3 and 4 of air
inlet control servomotor connector.
OK:

Resistance:

Damper Position

Resistance

REC side

3.4 – 6.4 k

Ω

FRS side

0.76 – 1.4 k

Ω

HINT:
As the air inlet control servomotor is moved from REC side to
FRS side, the voltage decreases gradually without interruption.

NG

Replace air mix control servomotor.

OK

3

Check harness and connector between A/C control assembly and air inlet con-
trol servomotor (See page

IN–27

).

NG

Repair or replace harness or connector.

OK

Check and replace A/C control assembly.

I00363

From HEATER Fuse

J20

B

B

J21

J/C

26

A13

L–B

9

A13

AMH

AMC

8

A13

G–R

P

2

1

Air Mix Control
Servomotor

W–B

W–B

J/C

A

A

II

A/C Control Assembly

A13

14

GND

L–B

–

DIAGNOSTICS

AIR CONDITIONING SYSTEM

DI–563

715

1997 LEXUS ES300 (RM511U)

DTC

41

Air Mix Control Servomotor Circuit

CIRCUIT DESCRIPTION

This air mix control sevomotor is controlled by the A/C control assembly and moves the air mix damper to
the disired position.

DTC No.

Detection Item

Trouble Area

41

Air mix damper position sensor value does not change even if

A/C control assembly operates air mix control servomotor.

Air mix control sevomotor

Air mix damper position sensor

Harness or connector between A/C control assembly and air

mix control servomotor, air mix damper position sensor.

A/C control assenbly.

WIRING DIAGRAM

DI0DH–01

AC3022

I00362

COOL

HOT

1

2

1

2

DI–564

–

DIAGNOSTICS

AIR CONDITIONING SYSTEM

716

1997 LEXUS ES300 (RM511U)

INSPECTION PROCEDURE

1

Actuator check

PREPARATION:
(a)

Warm up the engine.

(b)

Set to the actuator check mode (See page

DI–528

).

(c)

Press the DEF switch and change it to step operation.

CHECK:
Press the DEF switch and check the operation of the air mix
damper and the condition of the blower.
OK:

Display Code

Air Mix Damper

Condition

0 – 3

0 % (Fully closed)

Cool air comes out

4 – 5

50 %

6 – 9

100 % (Fully opened)

Warm air comes out

OK

Proceed to next circuit inspection shown on
matrix chart (See page

DI–535

).

NG

2

Check air mix control servomotor.

PREPARATION:
Remove ari mix control servomotor (See page

AC–73

).

CHECK:
Connect positive (+) lead to terminal 1 and the negative (–) lead
to terminal 2.
OK:

The lever turns smoothly to HOT side.

CHECK:
Connect negative (–) lead to terminal 1 and positive (+) lead to
terminal 2.
OK:

The lever turns smoothly to HOT side.

NG

Repair or replace harness or connector.

OK