Lexus RX300 (MCU15). Manual — part 262

DI–280

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DIAGNOSTICS

ABS & BA & TRC & VSC SYSTEM

LEXUS RX300 (RM785E)

INSPECTION PROCEDURE

1

Check for open and short circuit in harness and connector between steering
angle sensor and skid control ECU (See page IN–32).

NG

Repair or replace harness or connector.

OK

Check and replace skid control ECU.

F13429

Ignition Switch

Instrument Panel J/B

Skid Control ECU

Battery

W

4

2

B–Y

B–R

W–L

W–B

W–B

1C

II1

6

1

6

IG1

GND4

GND3

GND1

ECU–IG

AM1

W

J9
Junnction
Connector

W–B

GND2

1A

5E

11

1

8

17

W–B

W–B

Instrument Panel J/B

A22

31

1

2

7

1C

10

1D

A22

A22

A21

6

A21

IG

IF

A

7

5D

Fusible Link
Block
ALT

J/B No.5

W–B

W–B

5

3

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DIAGNOSTICS

ABS & BA & TRC & VSC SYSTEM

DI–281

LEXUS RX300 (RM785E)

DTC

Always ON*

Malfunction in ECU

*: ABS warning light

CIRCUIT DESCRIPTION

DTC No.

DTC Detecting Condition

Trouble Area

Always ON

Either of the following 1., 2. or 3. is detected:

1. Voltage of ECU terminal IG1 remains at more than 17 V.

2. The ECU connectors are off from the ECU.

3. There is a malfunction in the ECU internal circuit.

S Battery

S Charging system

S Power source circuit

S Skid control ECU

HINT:
There is a case that hand–held tester cannot be used when ECU is abnormal.

WIRING DIAGRAM

DI1GP–06

DI–282

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DIAGNOSTICS

ABS & BA & TRC & VSC SYSTEM

LEXUS RX300 (RM785E)

INSPECTION PROCEDURE

1

Check that the ECU connectors are securely connected to the ECU.

NO

Connect the connector to the ECU.

YES

2

Is DTC output?

Check DTC on page DI–205.

YES

Repair circuit indicated by the code output.

NO

3

Does ABS warning light go off?

YES

Check for open and short circuit in harness and
connector between ECU–IG fuse and ECU
(See page IN–32).

NO

4

Check battery voltage.

CHECK:
Check the battery voltage.
OK:

Voltage: 10 – 16 V

NG

Check and repair the charging system
(See page CH–2).

OK

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DIAGNOSTICS

ABS & BA & TRC & VSC SYSTEM

DI–283

LEXUS RX300 (RM785E)

5

Check operation of the ABS warning light.

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

Connect the hand–held tester to the DLC3.

(b)

Turn the ignition switch ON, and push the hand–held tester main switch ON.

(c)

Select the ACTIVE TEST mode on the hand–held tester.

CHECK:
Check that ”ON” and ”OFF” of the ABS warning light can be shown on the combination meter by the hand–
held tester.
In case of not using the hand–held tester:
PREPARATION:
(a)

Turn the ignition switch OFF.

(b)

Disconnect the connector from the skid control ECU.

(c)

Turn the ignition switch ON.

CHECK:
Check the ABS warning light goes off.

OK

Check and replace skid control ECU.

NG

Check for short circuit in harness and connector between combination meter and skid control
ECU, combination meter and DLC3 (See page IN–32).
Check ABS solenoid relay circuit (See page DI–237).