Lexus ES300 (2002 year). Manual - part 307

F43003

1 (+)

11 (-)

9 (+)

2 (-)

3 (+)

F04441

(Reference)

3 ms

2,288 

µ

s

104 

µ

s

5 V

0 V

5 V

0 V

ÇÇ

ÇÇ

-

DIAGNOSTICS

ABS WITH EBD & BA & TRAC & VSC SYSTEM

05-347

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2002 LEXUS ES300 REPAIR MANUAL   (RM911U)

3

INSPECT STEERING SENSOR

(a)

Remove the steering wheel and column lower cover (See
page 

50-8

).

(b)

Disconnect the steering angle sensor connector.

(c)

Apply battery positive voltage between terminals 1 and 2,
2 and 9.

(d)

Connect the oscilloscope to the terminals 3 and 11 of the
steering angle sensor.

(e)

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 SKID CONTROL ECU ASSY

F41986

Skid Control ECU

GL1

GL2

YAW

GYAW

YSS

W

B-Y

3

Passenger Side J/B

Battery

IA

FL MAIN

3B

6

4

2R

B-G

4

2

AM1

IG1

IG1

VYS

GL1

GL2

YAW2

VYS

GYAW

5

1

2

2E

2L

2A

2A

8

2

2

8

2

1

8

5

Y

L

W

R

B

S6

S6

S6

S6

S6

S6

S7

1

1

1

2

ALT

Engine Room R/B

B-G

W-B

B-R

3B

ECU-IG

AM1

I14
Ignition SW

IG Relay

Driver Side J/B

21

22

10

1

20

3

7

W

68

27

W

(Shielded)

S6

16

YD

Y1 
Yaw Rate Sensor

G

6

YD

05-348

-

DIAGNOSTICS

ABS WITH EBD & BA & TRAC & VSC SYSTEM

501

2002 LEXUS ES300 REPAIR MANUAL   (RM911U)

DTC

C1232/32 MALFUNCTION IN DECELERATION SENSOR

DTC

C1244/44 OPEN OR SHORT IN DECELERATION

SENSOR CIRCUIT

CIRCUIT DESCRIPTION

This sensor detects deceleration on the vehicle. The sensor signal is used in ABS & BA & TRAC & VSC
control. If the sensor functions abnormally, the ABS warning light comes on.

DTC No.

DTC Detecting Condition

Trouble Area

C1232/32

While vehicle speed becomes 0 km/h (0 mph) from 30 km/h
(18 mph), and the condition that GL1 and GL2 signals of
ECU terminals did not change 40 mV or less continued in a
sequence 16 times.

C1244/44

Either of the following 1., 2., 3. or 4. is detected:
1. The condition that ECU terminals GL1 and GL2 values

are 1.5G or less or 1.5G or more continues for 1.2 sec.

or more.

2. The condition that the deceleration sensor terminal VGS

voltage is 4.4 V or less or 5.6 G or more continues for

1.2 sec. or more.

3. At the vehicle speed of 0 km (0 mph), after the differ-

ence of output value between deceleration sensor termi-

nals GL1 and GL2 becomes 0.6 G or more, and the

condition that does not become 0.4 G or less continues

for 60 sec. or more.

4. Deceleration sensor signal momentary open occurs for

7 times or more.

Deceleration  sensor

Deceleration  sensor  circuit

WIRING DIAGRAM

052B3-03

F12707

GL1

GYAW

GL2

VYS

Forward

Rearward

Front

-

DIAGNOSTICS

ABS WITH EBD & BA & TRAC & VSC SYSTEM

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2002 LEXUS ES300 REPAIR MANUAL   (RM911U)

INSPECTION PROCEDURE

1

CHECK HARNESS AND CONNECTOR(YAW RATE SENSOR (DECELERATION
SENSOR) - SKID CONTROL ECU ASS)(See page 

01-31

)

NG

REPAIR OR REPLACE HARNESS OR
CONNECTOR

OK

2

INSPECT YAWRATE SENSOR(DECELERATION SENSOR)

(a)

Remove the consol box.

(b)

Connect 3 dry batteries of 1.5 V in series.

(c)

Connect VYS terminal to the batteries’ positive (+) termi-
nal, and GYAW terminal to the batteries’ negative (-) ter-
minal. Apply about 4.5 V between VYS and GYAW termi-
nals.

NOTICE:
Do not apply voltage of 6 V or more to terminals VYS and
GYAW.
(d)

Check the output voltage of GL1 and GL2 terminals when
the sensor is tilted forward and rearward.
OK:

Symbols

Condition

Standard Value

GL1

Horizontal

About 2.3 V

GL1

Lean forward

0.4 V - about 2.3 V

GL1

Lean rearward

About 2.3 V - 4.1 V

GL2

Horizontal

About 2.3 V

GL2

Lean forward

About 2.3 V - 4.1 V

GL2

Lean rearward

0.4 V - about 2.3 V

HINT:

If the sensor is tilted too much it may show the wrong val-
ue.

If dropped, the sensor should be replaced with a new one.

The sensor removed from the vehicle should not be
placed upside down.

NG

REPLACE YAWRATE SENSOR

OK

CHECK AND REPLACE SKID CONTROL ECU ASSY

F41987

Skid Control ECU

Passenger Side J/B

Battery

2

S8

GND1

3

15

22

IA

Engine Room R/B

Driver Side J/B

I14 
Ignition SW

27

7

S7

FL MAIN

B-R

IG1

AM1

IG1

3

W-B

ALT

B-G

4

W

1

2

5

2

S5

S5

S8

GND2

GND3

GND4

6

2L

8

2A

2

2

2E

8

2R

2A

AM1

ECU-IG

IG Relay

B-Y

B-G

W-B

1

1

W-B

W-B

W-B

3B

68

3B

2

1

W

ED

EA

05-350

-

DIAGNOSTICS

ABS WITH EBD & BA & TRAC & VSC SYSTEM

503

2002 LEXUS ES300 REPAIR MANUAL   (RM911U)

DTC

C1241/41 LOW BATTERY POSITIVE VOLTAGE OR

ABNORMALLY HIGH BATTERY POSITIVE
VOLTAGE

CIRCUIT DESCRIPTION

DTC No.

DTC Detection Condition

Trouble Area

C1241/41

Condition 1. or 2. is detected:

1. Vehicle speed is at 3 km/h (1.9 mph) or more and ECU

terminal IG1 voltage is 9.5 V or less, which continues for

10 sec. or more

2. When IG1 terminal voltage is less than 9.5 V, there is

open circuit in the motor relay or

 

in the solenoid relay, or

the solenoid circuit malfunction.

Power source harness and connector

Battery

Charging system

Power source circuit

WIRING DIAGRAM

055W0-02