Lexus ES300 (2002 year). Manual - part 284

F41940

IG

Battery

I15
Ignition SW

W

B-G

ECU-IG

25

B-R

21

2E

5

2A

2

1

AM1

IG1

AM1

B-Y

2

2G

2

3

FL MAIN

2R

S1

ALT

1

Skid Control ECU 
with Actuator

Engine Room R/B

8

IA

4

2A

IG1 Relay

2

8

B-G

1

1

2

B-G

Driver Side J/B

W-B

-

DIAGNOSTICS

ABS WITH EBD SYSTEM

05-265

418

2002 LEXUS ES300 REPAIR MANUAL   (RM911U)

DTC

C1241/41 LOW BATTERY POSITIVE VOLTAGE OR

ABNORMALLY HIGH BATTERY POSITIVE
VOLTAGE

CIRCUIT DESCRIPTION

This is the power source for the ECU and hence for the CPU and ABS actuator.

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 IG voltage is 9.5 V or less, which continues for

10 sec. or more

2. When IG 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

055XR-02

F41241

ECU-IG

F13038

(+)

(-)

24

25

ON

2

05-266

-

DIAGNOSTICS

ABS WITH EBD SYSTEM

419

2002 LEXUS ES300 REPAIR MANUAL   (RM911U)

INSPECTION PROCEDURE

1

INSPECT FUSE(ECU-IG OF DRIVER SIDE J/B)

(a)

Remove the ECU-IG fuse from the driver side J/B.

(b)

Check the continuity of the ECU-IG fuse.
OK: Continuity

NG

REPLACE FUSE

OK

2

INSPECT BATTERY(TERMINAL VOLTAGE)

OK: 10 - 14 V

NG

CHECK AND REPLACE CHARGING SYSTEM

OK

3

CHECK VOLTAGE OF ECU IG POWER SOURCE

In case of using the hand-held tester:
(a)

Select the item ”IG VOLTAGE” in the DATA LIST and red its value displayed on the hand-held tester.

(b)

Check the voltage condition output from the ECU and displayed on the hand-held tester.
OK: ”Normal” is displayed.

In case of not using the hand-held tester:
(a)

Disconnect the skid control ECU connector.

(b)

Turn the ignition switch ON.

(c)

Measure the voltage between terminals 25 and 2 or 24 of
the skid control ECU connector.
OK: 10 - 14 V

OK

CHECK AND REPLACE BRAKE ACTUATOR
ASSY

NG

F13039

24

2

LOCK

-

DIAGNOSTICS

ABS WITH EBD SYSTEM

05-267

420

2002 LEXUS ES300 REPAIR MANUAL   (RM911U)

4

CHECK CONTINUITY(GND OF SKID CONTROL ECU CONNECTOR  -  BODY
GROUND)

(a)

Measure the resistance between terminals 2 and 24 of
the skid control ECU connector and the body ground.
OK: 1 

Ω

 or less

NG

CHECK AND REPAIR HARNESS AND
CONNECTOR

OK

CHECK AND REPLACE BRAKE ACTUATOR ASSY

F41974

STP

S13
Stop Light SW

2

19

S1

10

G-W

ST+

15

1

W-B

J12 
J/C

W

A

7

From Battery

7

2K

2G

2E

G-W

Driver Side J/B

2

Skid Control ECU 
with Actuator

BC

BE

2G

G-W

G-W

G-W

R12 
Rear Combination 
Light LH

2G

13

1

STOP

STOP

R14
Rear Combination 
Light RH

3

W-B

1

1

3

ST-

L4 
Light Failure Sensor

STOP

G-W

05-268

-

DIAGNOSTICS

ABS WITH EBD SYSTEM

421

2002 LEXUS ES300 REPAIR MANUAL   (RM911U)

DTC

C1249/49 OPEN CIRCUIT IN STOP LIGHT SWITCH

CIRCUIT

CIRCUIT DESCRIPTION

DTC No.

DTC Detection Condition

Trouble Area

C1249/49

ECU terminal IG voltage is 9.5 V to 18.5 V and ABS is in

non-operation, the open circuit of the stop light switch cir-

cuit continues for 0.3 sec. or more.

Stop lamp switch harness and connector

Stop light bulb

Stop light switch circuit

Stop lamp switch

WIRING DIAGRAM

055XS-02