Lexus ES300 (2002 year). Manual - part 343

F41642

Driver Side J/B:

FAN RLY
Fuse

C91403

F41638

+B (+)

GND (-)

A22

-

DIAGNOSTICS

ELECTRONIC MODULATED SUSPENSION SYSTEM

05-215

368

2002 LEXUS ES300 REPAIR MANUAL   (RM911U)

INSPECTION PROCEDURE

1

INSPECT SOURCE VOLTAGE

(a)

Check the battery positive voltage.
OK:
Voltage: 10 - 14 V

NG

REPLACE BATTERY

OK

2

INSPECT FUSE(FAN RLY)

(a)

Remove the FAN RLY fuse from the driver side J/B.

(b)

Check continuity of FAN RLY fuse.
OK: 
Continuity

NG

INSPECT FOR SHORT CIRCUIT IN ALL
HARNESSES AND COMPONENTS
CONNECTED TO FAN RLY FUSE

OK

3

INSPECT ABSORBER CONTROL ECU

(a)

Remove the absorber control ECU with connectors still
connected.

(b)

Turn the ignition switch to ON, measure voltage between
terminals A22 - 1 (+B) and A22 - 14 (GND) of the absorb-
er control ECU connector.
OK: 
Voltage: 10 - 14 V

OK

CHECK AND REPLACE ABSORBER CONTROL
ECU(See page 

01-31

)

NG

C91692

F41639

GND

A22

05-216

-

DIAGNOSTICS

ELECTRONIC MODULATED SUSPENSION SYSTEM

369

2002 LEXUS ES300 REPAIR MANUAL   (RM911U)

4

CHECK HARNESS OR CONNECTOR(ABSORBER CONTROL ECU - BODY
GROUND)

(a)

Disconnect the absorber control ECU connectors.

(b)

Turn the ignition switch to ON.

(c)

Measure resistance between terminal A22 - 14 (GND)
and body ground.
OK: 
Continuity

NG

REPAIR OR REPLACE HARNESS OR
CONNECTOR

OK

CHECK AND REPLACE ABSORBER CONTROL ECU(See page 

01-31

)

F41650

Absorber Control ECU

A22 FRO

17

25

GR-R

IF2

J5 
J/C

B

(*1)

(*2)

IF8

3

S7

13

20

S1

Skid Control ECU Assy

Skid Control ECU Assy

*1: w/ VSC 
*2: w/o VSC

GR-R

B

GR-R

GR-R

FRO

FRO

(*2)

GR-R

GR-R

-

DIAGNOSTICS

ELECTRONIC MODULATED SUSPENSION SYSTEM

05-217

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2002 LEXUS ES300 REPAIR MANUAL   (RM911U)

DTC

C1776/76 RIGHT FRONT SPEED SENSOR CIRCUIT

DTC

C1794/94 RIGHT FRONT SPEED SENSOR CIRCUIT

CIRCUIT DESCRIPTION

The speed sensor detects the wheel speed and transmits the appropriate vehicle speed signal to the absorb-
er ECU through the skid control ECU assy.

DTC No.

DTC Detecting Condition

Trouble Area

C1776/76

Right front speed sensor circuit malfunction

Right front speed sensor

Right front speed sensor circuit

C1794/94

Right front speed signal 20 km/h (12 mph) or more

Right front s eed sensor circuit

Skid control ECU assy

Absorber control ECU

WIRING DIAGRAM

056AD-01

05-218

-

DIAGNOSTICS

ELECTRONIC MODULATED SUSPENSION SYSTEM

371

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 turn the hand-held tester main switch to ON.

(c)

Select the item ”WHEEL SPD FR” in the DATA LIST and read its value displayed on the hand-held
tester.

(d)

Check that there is no difference between the speed value output from the speed sensor displayed
by the hand-held tester and the speed value displayed by the speedometer when driving the vehicle.
OK:
There is almost no difference in the displayed speed value.

HINT:
There is tolerance of 

10 % in the speedometer indication.

OK

CHECK AND REPLACE ABSORBER CONTROL
ECU(See page 

01-31

)

NG

2

CHECK DIAGNOSTIC CODE OUTPUT

(a)

Check that DTC for ABS output the normal code.

NG

REPAIR CIRCUIT INDICATED BY OUTPUT
CODE

OK

3

CHECK HARNESS OR CONNECTOR(ABSORBER CONTROL ECU - SKID
CONTROL ECU ASSY)

(a)

Check for open and short circuit in harness and connector between absorber control ECU and skid
control ECU assy (See page 

01-31

).

NG

REPAIR OR REPLACE HARNESS OR
CONNECTOR

OK

CHECK AND REPLACE ABSORBER CONTROL ECU(See page 

01-31

)