Lexus RX300 (MCU15). Manual - part 255

DI–252

–

DIAGNOSTICS

ABS & BA & TRC & VSC SYSTEM

LEXUS RX300   (RM785E)

DTC

C1223 / 43

ABS Control System Malfunction

CIRCUIT DESCRIPTION

DTC No.

DTC Detecting Condition

Trouble Area

C1223 / 43

ABS control system is abnormal.

ABS control system

INSPECTION PROCEDURE

1

Check the DTC for the ABS (See page DI–205).

*1

Repair ABS control system according to the
code output.

*2

Check for ECU connected to malfunction in-
dicator light.

*1: Output NG code
*2: Malfunction indicator light remains ON

DI1H3–09

F02660

Engine and ECT ECU

Skid Control ECU

E10

NEO

7

A22

16

NEO

L–O

–

DIAGNOSTICS

ABS & BA & TRC & VSC SYSTEM

DI–253

LEXUS RX300   (RM785E)

DTC

C1224 / 44

NE Signal Circuit

CIRCUIT DESCRIPTION

The skid control ECU receives engine revolution speed signals (NE signals) from the engine and ECT ECU.

DTC No.

DTC Detecting Condition

Trouble Area

C1224 / 44

At vehicle speed of 30 km/h (19 mph) or more, when data

receiving from the engine and ECT ECU is in normal condi-

tion, and open or short circuit for engine revolution signal

circuit continues for 10 sec. or more.

S NEO circuit

S Engine and ECT ECU

WIRING DIAGRAM

DI1H4–10

F02807

ON

NEO

(+)

(–)

F03007

(Reference)

3 – 6 V

Below 1 V

DI–254

–

DIAGNOSTICS

ABS & BA & TRC & VSC SYSTEM

LEXUS RX300   (RM785E)

INSPECTION PROCEDURE

1

Check for open and short circuit in harness and connector between terminal
NEO of skid control ECU and terminal NEO of engine and ECT ECU 
(See page IN–32).

NG

Repair or replace harness and connector.

OK

2

Check voltage between terminals NEO of skid control ECU and body ground.

PREPARATION:
(a)

Remove skid control ECU with connectors still con-
nected.

(b)

Turn ignition switch ON.

CHECK:
Measure voltage between terminal NEO of skid control ECU
and body ground for the engine conditions below.
OK:

Engine condition

Voltage

OFF (IG ON)

3 – 6 V or below 1 V

ON (Idling)

3 – 6 V ↔ below 1 V (Pulse)

NG

Check and replace skid control ECU or engine
and ECT ECU.

OK

If the same codes is still output after the DTC is deleted, check the contact condition of each con-
nection.

F13428

IG

SS1+

SS1–

ESS

14

ECU–IG

1C

23

A23 SS1+

4

SS1–

Instrument Panel J/B

ALT

Skid Control ECU

B–R

Steering Angle Sensor

2

6

3

2

LG–B

LG

1

B–Y

W–L

IG

AM1

1D

10

A23

7

Ignition Switch

1C

6

2

1

1

1A

W

Instrument Panel J/B

5

3

FL Block

Battery

J9
Junction
Connector

A

W–B

IG1 AM1

W

–

DIAGNOSTICS

ABS & BA & TRC & VSC SYSTEM

DI–255

LEXUS RX300   (RM785E)

DTC

C1231 / 31

Steering Angle Sensor Circuit

CIRCUIT DESCRIPTION

DTC No.

DTC Detecting Condition

Trouble Area

C1231 / 31

The condition that the data is not transmitted to the steering

angle sensor continues for more than 1.2 sec.

S Steering angle sensor

S Steering angle sensor circuit

WIRING DIAGRAM

DI1H5–06