Lexus SC300 / Lexus SC400. Manual - part 4

FRONT AIRBAG SENSOR

1. 

Never reuse the front airbag sensors involved in a collision
when the airbag has deployed. (Replace both the left and
right airbag sensors.)

2. 

Install the front airbag sensor with the arrow on the sensor
facing toward the front of the vehicle.

3. 

The front airbag sensor set bolts have been anti–rust treated.
When the sensor is removed, always replace the set bolts
with new ones.

4. The 

front 

airbag 

sensor 

is 

equipped 

with 

an 

electrical

connection check mechanism. Be sure to lock this
mechanism securely when connecting the connector. If the
connector is not securely locked, a malfunction code will be
detected by the diagnosis system (See page 

AB–10

).

SPIRAL CABLE (IN COMBINATION
SWITCH)

The steering wheel must be fitted correctly to the steering column
with the spiral cable at the neutral position; otherwise cable dis-
connection and other troubles may result. Refer to page 

AB–15

of this manual concerning correct steering wheel installation.

STEERING WHEEL PAD (WITH AIRBAG)

1. 

When removing the steering wheel pad or handling a new
steering wheel pad, it should be placed with the pad top
surface facing up.
In this case, the twin–lock type connector lock lever should
be in the locked state and care should be taken to place it so
the connector will not be damaged. And do not store a steer-
ing wheel pad on top of another one. (Storing the pad with its
metallic surface up may lead to a serious accident if the air-
bag inflates for some reason.)

2. 

Never measure the resistance of the airbag squib. (This
may  cause the  airbag to  deploy,  which  is  very
dangerous.)

IN–10

–

INTRODUCTION

Precautions for Vehicles Equipped with SRS Airbag

3. 

Grease should not be applied to the steering wheel pad and
the pad should not be cleaned with detergents of any kind.

4. 

Store the steering wheel pad where the ambient temperature
remains below 93

C (200

F), without high humidity and

away from electrical noise.

5.  When using electric welding, first disconnect the airbag

connector (yellow color and 2 pins) under the steering
column near the combination switch connector before
starting work.

6. 

When disposing of a vehicle or the steering wheel pad
alone, the airbag should be deployed using an SST
before disposal (See  page 

AB–91

). Perform the

operation in a place away from electrical noise.

CENTER AIRBAG SENSOR ASSEMBLY

The connector to the center airbag sensor assembly should be
connected or disconnected with the sensor mounted on the floor.
If the connector is connected or disconnected while the center air-
bag sensor assembly is not mounted to the floor, it could cause un-
desired ignition of the airbag system.

WIRE HARNESS AND CONNECTOR

The airbag system’s wire harness is integrated with the cowl wire
harness assembly. The wires for the airbag wire harness are en-
cased in a yellow corrugated tube. All the connectors for the sys-
tem are also a standard yellow color. If the airbag system wire har-
ness becomes disconnected or the connector becomes broken
due to an accident, etc., repair or replace it as shown on page

AB–22

.

–

INTRODUCTION

Precautions for Vehicles Equipped with SRS Airbag

IN–11

PRECAUTIONS FOR VEHICLES
EQUIPPED WITH A CATALYTIC
CONVERTER

CAUTION: If large amounts of unburned gasoline flow into the
converter, it may overheat and create a fire hazard. To prevent
this, observe the following precautions and explain them to
your customer.
1. 

Use only unleaded gasoline.

2. 

Avoid prolonged idling.
Avoid running the engine at idle speed for more than 20 min-
utes.

3. 

Avoid spark jump test.
(a) Perform spark jump test only when absolutely

necessary. Perform this test as rapidly as possible.

(b)  While testing, never race the engine.

4. 

Avoid prolonged engine compression measurement.
Engine compression tests must be done as rapidly as pos-
sible.

5. 

Do not run engine when fuel tank is nearly empty.
This may cause the engine to misfire and create an extra load
on the converter.

6.  Avoid coasting with ignition turned off and prolonged

braking.

7. 

Do not dispose of used catalyst along  with parts
contaminated with gasoline or oil.

IN–12

–

INTRODUCTION

Precautions for Vehicles Equipped with a Catalytic
Converter

PRECAUTIONS FOR VEHICLES
EQUIPPED WITH TRACTION
CONTROL (TRAC) SYSTEM

When using a rear wheel two–wheel drum tester such as a
speedometer tester or chassis dynamometer, etc., or jacking up
the rear wheels and driving the wheels, always push in the TRAC
cut (”TRAC OFF”) switch and turn the TRAC system OFF.

CONFIRM TRAC SYSTEM IS OFF
1. 

Press the TRAC cut (”TRAC OFF”) switch.

2. 

Check that the TRAC OFF indicator light comes on when the
TRAC system is turned off by the TRAC cut switch.

HINT: The TRAC indicator light should always operate right after
the engine is restarted.

3. Begin 

measurements.

4. 

Press the TRAC cut switch again to change the TRAC to
operative and check that the TRAC OFF indicator light goes
off.

HINT: The TRAC indicator light blinks when the TRAC system is
operative.

–

INTRODUCTION

Precautions for Vehicles Equipped with Traction Cotnrol
(TRAC)System

IN–13