Lexus ES300 (2002 year). Manual - part 344

F41651

SS2+

SS2-

A21

9

R

8

G

IF2

7

6

4

12

IG

ESS

1

2

B-R

W-B

A

J1 
J/C

IB

IA

Absorber Control ECU

Steering Sensor

To Ignition SW

A21

IF2

R

G

SS2+

SS2-

W-B

W-B

J4 
J/C

A

A

A

-

DIAGNOSTICS

ELECTRONIC MODULATED SUSPENSION SYSTEM

05-219

372

2002 LEXUS ES300 REPAIR MANUAL   (RM911U)

DTC

C1777/77 STEERING ANGLE SENSOR CIRCUIT

CIRCUIT DESCRIPTION

The steering sensor is mounted on the combination switch assy, and detects the steering wheel angle and
its direction.

DTC No.

DTC Detecting Condition

Trouble Area

C1777/77

Steering sensor system signal is abnormal.

Steering sensor

Steering angle sensor circuit

Absorber control ECU

WIRING DIAGRAM

056AE-01

C91403

F41638

+B (+)

GND (-)

A22

05-220

-

DIAGNOSTICS

ELECTRONIC MODULATED SUSPENSION SYSTEM

373

2002 LEXUS ES300 REPAIR MANUAL   (RM911U)

INSPECTION PROCEDURE

HINT:
Start the inspection from the step 1 in case of using hand-held tester and start from step 2 in case of not
using hand-held tester.

1

READ VALUE OF HAND-HELD TESTER

(a)

Connect the hand-held tester to the DLC3.

(b)

Turn the ignition switch to ON and push the hand-held tester main switch ON.

(c)

Select the item ”STEERING ANGLE” in the DATA LIST and read its value displayed on the hand-held
tester.

(d)

Check that the steering wheel turning angle value of the steering angle position sensor displayed on
the hand-held tester is changing when turning the steering wheel.
OK: 
Steering wheel turning angle value must be changing.

NG

CHECK AND REPLACE ABSORBER CONTROL
ECU(See page 

01-31

)

OK

2

INSPECT ABSORBER CONTROL ECU

(a)

Remove the absorber control ECU with the connector still
connected.

(b)

Turn the ignition switch to ON.

(c)

Measure voltage between terminal A22 -1 (+B) and A22
-  14 (GND) of the absorber control ECU.
OK: 
Voltage 10 - 14 V

NG

REPAIR OR REPLACE HARNESS OR
CONNECTOR

OK

F41640

ESS (-)

IG1 (+)

BAT (+)

C90512

ESS (-)

IG1 (+)

BAT (+)

SS2-

SS2+

F04441

(Reference)

3 ms

2,288 

µ

s

104 

µ

s

5 V

0 V

5 V

0 V

ÇÇ

ÇÇ

-

DIAGNOSTICS

ELECTRONIC MODULATED SUSPENSION SYSTEM

05-221

374

2002 LEXUS ES300 REPAIR MANUAL   (RM911U)

3

CHECK HARNESS AND CONNECTOR(STEERING SENSOR)

(a)

Disconnect the steering sensor connector.

(b)

Turn the ignition switch ON.

(c)

Measure voltage between terminal 1 (IG1) and 2 (ESS),
2 (ESS) and 9 (BAT) of the steering sensor harness side
connector.
OK: 
Voltage 10 - 14 V

NG

REPAIR OR REPLACE HARNESS OR
CONNECTOR

OK

4

INSPECT STEERING SENSOR

(a)

Disconnect the steering angle sensor connector.

(b)

Apply battery positive voltage between terminals 1 (IG1)
and 2 (ESS), 2 (ESS) and 9 (BAT).

(c)

Connect the oscilloscope to the terminals 4 (SS2+) and
12 (SS2-) of the steering angle sensor.

(d)

Turn the steering column shaft slowly and check the sig-
nal waveform.
OK:

HINT:
The above signal waveform does not repeat ON and OFF regu-
larly and this ON-OFF interval changes case by case according
to the data.

NG

REPLACE STEERING SENSOR

OK

CHECK AND REPLACE ABSORBER CONTROL ECU(See page 

01-31

)

F41652

Absorber Control ECU

TACH

E6

ECM

B-O

11

A21

5

TACH

05-222

-

DIAGNOSTICS

ELECTRONIC MODULATED SUSPENSION SYSTEM

375

2002 LEXUS ES300 REPAIR MANUAL   (RM911U)

DTC

C1779/79 CRANKSHAFT POSITION SENSOR CIRCUIT

DTC

C1797/97 CRANKSHAFT POSITION SENSOR CIRCUIT

CIRCUIT DESCRIPTION

The absorber control ECU receives the engine speed signal from the ECM.

DTC No.

DTC Detecting Condition

Trouble Area

C1779/79
C1797/97

With engine speed is less than 2,000 rpm, or any signal is
not input at all.

Crankshaft position sensor

Crankshaft position sensor circuit

ECM

Absorber control ECU

WIRING DIAGRAM

056AF-01