Lexus ES300 (2002 year). Manual - part 345

F41637

TACH

A21

GND

F41641

GND

5 V / Division 10 ms / Division

Normal Signal Waveform

About
13 V

-

DIAGNOSTICS

ELECTRONIC MODULATED SUSPENSION SYSTEM

05-223

376

2002 LEXUS ES300 REPAIR MANUAL   (RM911U)

INSPECTION PROCEDURE

1

CHECK HARNESS AND CONNECTOR(ABSORBER CONTROL ECU - ECM)

(a)

Check for open and short circuit in harness and connector between terminal THCH of absorber control
and ECM (See page 

01-31

).

NG

REPAIR OR REPLACE HARNESS OR
CONNECTOR

OK

2

INSPECT ABSORBER CONTROL ECU(TACH OUTPUT)

(a)

Remove the absorber control ECU with connector still
connected.

(b)

Turn the ignition switch to ON.

(c)

Connect an oscilloscope to terminals A21 - 11 (TACH)
and A22 - 14 (GND) of the absorber control ECU harness
side connector.

(d)

With the engine idling, and check the signal waveform.
OK:
Signal wave form as shown in the illustration.

HINT:
As the engine speed becomes higher, the waveform cycle is
getting shorter.

NG

CHECK AND REPLACE ECM(See page 

01-31

)

OK

CHECK AND REPLACE ABSORBER CONTROL ECU(See page 

01-31

)

F41653

STP

2

A22

G-W

2G

19

7

1

2

W

To Battery

S15 
Stop Lamp Switch Assy

Driver Side J/B

Absorber Control ECU

G-W

2G

05-224

-

DIAGNOSTICS

ELECTRONIC MODULATED SUSPENSION SYSTEM

377

2002 LEXUS ES300 REPAIR MANUAL   (RM911U)

DTC

C1782/82 STOP LIGHT SWITCH CIRCUIT

CIRCUIT DESCRIPTION

When the brake pedal is depressed, the stop lamp goes on and the signal is input to the STP terminal of
absorber control ECU.

DTC No.

DTC Detecting Condition

Trouble Area

C1782/82

The signal from the stop lamp switch assy does not
change.

Stop lamp switch assy

Stop light switch circuit

Skid control ECU assy

Absorber control ECU

WIRING DIAGRAM

056AG-01

C91403

F41638

STP (+)

GND (-)

A22

C68829

F41663

-

DIAGNOSTICS

ELECTRONIC MODULATED SUSPENSION SYSTEM

05-225

378

2002 LEXUS ES300 REPAIR MANUAL   (RM911U)

INSPECTION PROCEDURE

1

CHECK STOP LAMP

(a)

Check that the stop lamp lights up when brake pedal is depressed and turns OFF when the brake pedal
is released.

NG

Go to step 3

OK

2

INSPECT ABSORBER CONTROL ECU

(a)

Remove the absorber control ECU with connectors still
connected.

(b)

Measure voltage between terminal A22 - 2 (STP) and
A22 - 14 (GND) of absorber control ECU when stop lamp
switch assy switch is ON and OFF.
OK:

Stop lamp switch assy

Voltage

ON

8 - 14

OFF

Below 1.5

NG

REPAIR OR REPLACE HARNESS OR
CONNECTOR

OK

CHECK AND REPLACE ABSORBER CONTROL ECU(See page 

01-31

)

3

INSPECT STOP LAMP SWITCH ASSY

(a)

Disconnect the stop lamp switch assy connector.

(b)

Measure the continuity between each terminal of the stop
lamp switch assy.
OK:

Terminal

Stop lamp switch assy

Specification

1 - 2

ON

Continuity

1 - 2

OFF

No continuity

3 - 4

ON

Continuity

3 - 4

OFF

No continuity

NG

REPLACE STOP LAMP SWITCH ASSY

OK

C91403

F41638

STP (+)

GND (-)

A22

05-226

-

DIAGNOSTICS

ELECTRONIC MODULATED SUSPENSION SYSTEM

379

2002 LEXUS ES300 REPAIR MANUAL   (RM911U)

4

INSPECT ABSORBER CONTROL ECU

(a)

Remove the absorber control ECU with connectors still
connected.

(b)

Measure voltage between terminal A22 - 2 (STP) and
A22 - 14 (GND) of absorber control ECU when stop lamp
switch assy switch is ON and OFF.
OK:

Stop lamp switch assy

Voltage

ON

8 - 14

OFF

Below 1.5

NG

REPAIR OR REPLACE HARNESS OR
CONNECTOR

OK

CHECK AND REPLACE ABSORBER CONTROL ECU(See page 

01-31

)