Lexus SC300 / Lexus SC400. Service manual — part 313

Fuel Pump ECU

Auto Antenna Motor and Relay

Power Seat ECU
(For Passenger’s Seat)

Power Seat ECU
(For Driver’s Seat)

CD Automatic Changer

Wireless Door Lock ECU

Moon Roof Control Relay

Locations of ECUs (Cont’d)

Many ECUs are mounted in this vehicle.
Take the following precautions during body repair to prevent damage to the ECUs.

Before starting electric welding operations, disconnect the negative (-) terminal cable from the battery.
When the negative (-) terminal cable is disconnected from the battery, memory of the clock and audio
systems will be cancelled. So before starting work, make a record of the contents memorized by each
memory system. Then when work is finished, reset the clock and audio systems as before.
When the vehicle has tilt and telescopic steering, power seat and outside rear view mirror, which are all
equipped with memory function, it is not possible to make a record of the memory contents.
So when the operation is finished, it will be necessary to explain this fact to the customer, and request
the customer to adjust the features and reset the memory.

Do not expose the ECUs to ambient temperatures above 80

°

C (176

°

F).

NOTICE: If it is possible the ambient temperature may reach 80

°

C (176

°

F) or, more, remove the ECUs

from the vehicle before starting work.

Be careful not to drop the ECUs and not to apply physical shocks to them.

5. COMPONENTS ADJACENT TO THE BODY PANELS

Various types of component parts are mounted directly on or adjacently to the body panels.
Strictly observe the following precautions to prevent damaging these components and the body panels
during handling.

Before repairing the body panels, remove their adjacent components or apply protective covers over
the components.

Before prying components off using a screwdriver or a scraper, etc., attach protective tape to the tool
tip or blade to prevent damaging the components and the body paint.

Before removing components from the outer surface of the body, attach protective tape to the body to
ensure no damage to painted areas.
HINT: Apply touch-up paint to any damaged paint surfaces.

Before drilling or cutting sections, make sure that there are no wires, hoses, etc., on the reverse side.

INTRODUCTION

IN-9

GENERAL REPAIR INSTRUCTIONS

Work Precautions

SAFETY
1.

Before performing repair work, check
for fuel leaks. If a leak is found, be sure
to close the opening totally.

2.

If it is necessary to use a frame in the
area of the fuel tank, first remove the
tank and plug the fuel line.

VEHICLE PROTECTION
When welding, protect the
painted surfaces, windows,
seats and carpet with heat
resistant, fire-proof covers.

SAFETY
Never stand in direct
line with the chain when
using a puller on the
body or frame, and be
sure to attach a safety
cable.

WRONG

Glass Cover

Safety Cable

Seat Cover

WRONG

SAFETY WORK CLOTHES

HAND TOOLS
Keeping your hand tools in
neat order improve your
work efficiency.

In addition to the usual mechanic’s wear, cap and safety shoes,
the appropriate gloves, head protector, glasses, ear plugs, face
protector, dust-prevention mask, etc. should be worn as, the
situation demands.

Dust-
Prevention
Mask

Welder’s
Glasses

Ear
Plugs

Body
Mechanic
Stand

Face
Protector

Head
Protector

Eye
Protector

Welder’s
Gloves

Safety
Shoes

INTRODUCTION

IN-10

Proper and Efficient Work Procedures

REMOVAL

NUMBER OF SPOT WELDS AND PANEL POSITIONS
The number of spot welds and the panel positions to be
removed are shown for your reference.
HINT: See ”Symbols ” on page

IN-4

,

5

.

PRE-REMOV AL MEASURING
Before removal or cutting
operations, take measurements
in accordance with the dimen-
sion diagram. Always use a
puller to straighten a damaged
body or frame.

REMOVAL of ADJACENT COMPONENTS
When removing adjacent components, ap-
ply protective tape to the surrounding body
and your tools to prevent damage.
HINT: See ”Handling Precautions on
Related Components ” on page

IN-9

.

PRECAUTIONS FOR DRILLING OR
CUTTING
Check behind any area to be drilled or
cut to insure that there are no hoses,
wires, etc., that may be damaged.
HINT: See ”Handling Precautions on
Related Components ” on page

IN-9

.

CUTTING AREA
Always cut in a straight
line and avoid reinforced
areas.

Cutting Okay

Corners

Reinforcement

WRONG

INTRODUCTION

IN-11

Thickness of
welded portion

Size of plug hole

1.0 (0.04) under

5 (0.20)

φ

over

1.0 (0.04) - 1.5 (0.06)

6.5 (0.26)

φ

over

1.5 (0.06) over

8 (0.31)

φ

over

REFERENCE:

mm (in.)

PREPARATION FOR INSTALLATION

SPOT WELD POINTS

APPLICATION OF WELD-THROUGH PRIMER
(SPOT SEALER)

Less than
3 mm

Remove the paint from
the portion of the new
parts and body to be
welded, and apply
weld-through primer.
HINT: See ”ANTI-
RUST TREATMENT ”
on page

AR-9

.

When welding panels with a
combined thickness of over
3 mm (0.12 in.), use a MIG
(Metal Inert Gas) welder for
plug welding.
HINT: Spot welding will not
provide sufficient durability
for panels over 3 mm (0.12
in.) thick.

Air Saw

WRONG

Puncher

20 - 30 mm

Overlap

ROUGH CUTTING OF JOINT
For joint areas, rough
cut the new parts, leaving
20 - 30 mm (0.79 - 1.18 in.)
overlap.

MAKING HOLES FOR PLUG WELDING
For areas where a spot welder cannot
be used, use a puncher or drill to make
holes for plug welding.

INTRODUCTION

IN-12