Lexus ES300 (2002 year). Service manual — part 309

F12707

GL1

GYAW

GL2

VYS

Forward

Rearward

Front

-

DIAGNOSTICS

ABS WITH EBD & BA & TRAC & VSC SYSTEM

05-355

508

2002 LEXUS ES300 REPAIR MANUAL (RM911U)

5

INSPECT YAWRATE SENSOR(INCLUDE 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

6

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

01-31

)

NG

END

OK

CHECK AND REPLACE SKID CONTROL ECU ASSY

R

F41989

ABS & Traction Actuator

Skid Control ECU

13

FSS

S5

S5

S5

S5

S5

S5

S5

S5

A5

A5

A5

A5

A5

A5

GSS

PMC

VCM

E2

PMC2

VCM2

E3

10

20

19

11

18

21

12

(Shielded)

(Shielded)

7

6

16

15

14

5

PMC

VCM

E2

PMC2

VCM2

E3

B

W

W

B

R

05-356

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DIAGNOSTICS

ABS WITH EBD & BA & TRAC & VSC SYSTEM

509

2002 LEXUS ES300 REPAIR MANUAL (RM911U)

DTC

C1246/46 MALFUNCTION IN MASTER CYLINDER

PRESSURE SENSOR

DTC

C1360/61 MALFUNCTION IN COMPARATIVE MASTER

CYLINDER PRESSRRE SENSOR

CIRCUIT DESCRIPTION

DTC No.

DTC Detecting Condition

Trouble Area

C1246/46

C1360/61

Either of the following 1., 2., 3., or 4. is detected:
1. At the vehicle speed of 7 km/h (4 mph) or more, master

cylinder pressure sensor does not change continues for

30 sec.

2. Interference occurs 7 times or more for 5 sec.

3. ECU terminal STP is OFF, and the condition that master

cylinder pressure sensor voltage becomes more than

0.86 V or less than 0.3 V continues for 5 sec. or more.

4. Master cylinder pressure sensor circuit is open or short

for 1.2 sec. or more.

Master cylinder pressure sensor

Master cylinder pressure sensor circuit

WIRING DIAGRAM

055W2-02

F40456

E3

PMC

VCM2

VCM E2

PMC2

-

DIAGNOSTICS

ABS WITH EBD & BA & TRAC & VSC SYSTEM

05-357

510

2002 LEXUS ES300 REPAIR MANUAL (RM911U)

INSPECTION PROCEDURE

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

1

READ VALUE OF HAND-HELD TESTER(MASTER CYLINDER PRESSURE
SENSOR OUTPUT VALUE)

(a)

Select the item ”MAS CYL PRESS 1, MAS CYL PRESS 2”in the DATA LIST and read its value dis-
played on the hand-held tester.

(b)

Check that the brake fluid pressure value of the master cylinder pressure sensor displayed on the
hand-held tester is changing when depressing the brake pedal.
OK: Brake fluid pressure value must be changing.

OK

Go to step 4

NG

2

INSPECT SKID CONTROL ECU TERMINAL VOLTAGE(PMC, PMC2 TERMINAL
VOLTAGE)

(a)

Install LSPV gauge to the front brake caliper bleeder plug
portion, and bleed air from LSPV gauge.

(b)

Start the engine and depress the brake pedal, then check
the relation between the fluid pressure and voltage of
PMC and E2, PMC2 and E3 terminals of the skid control
ECU with connector still connected.
OK:

Front brake caliper fluid pressure

Voltage

0 kPa (0 Kgf/cm

2

, 0 psi)

0.37 - 0.63 V

5,883 kPa (60 kgf/cm

2

, 853 psi)

1.57 - 1.83 V

11,768 kPa (120 kgf/cm

2

, 1,706 psi)

2.77 - 3.03 V

HINT:
Voltage between terminals VCM and E2, VCM2 and E3: 4.7 -
5.3 V

OK

Go to step 4

NG

3

CHECK HARNESS AND CONNECTOR(MASTER CYLINDER PRESSURE SENSOR
- SKID CONTROL ECU ASSY)

NG

REPAIR OR REPLACE HARNESS OR
CONNECTOR

OK

REPLACE ABS & TRACTION ACTUATOR ASSY

F40456

STP

05-358

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DIAGNOSTICS

ABS WITH EBD & BA & TRAC & VSC SYSTEM

511

2002 LEXUS ES300 REPAIR MANUAL (RM911U)

4

CHECK SKID CONTROL ECU TERMINAL VOLTAGE(STP TERMINAL)

(a)

Remove the skid control ECU with connectors still con-
nected.

(b)

Measure voltage between terminal STP of skid control
ECU and body ground when brake pedal is depressed.
OK: 8 - 14 V

(c)

Measure voltage between terminal STP of skid control
ECU and body ground when brake pedal is released.
OK: Below 1.5 V

NG

REPAIR OR REPLACE STOP LAMP SWITCH
CIRCUIT

OK

CHECK AND REPLACE SKID CONTROL ECU ASSY