1991 LEXUS SC400 EFI

FuseCheck forTester ConnectionConditionSpecified value
HTRVoltage(15)±GroundConstantBattery voltage
DEF(17)±Ground
DOME(24)±Ground
EFI(26)±Ground
HAZ±HORN(28)±Ground
RADIO NO. 1(30)±Ground
TEL(32)±Ground
ALT±S(34)±Ground
TRAC(36)±Ground
HEAD (RH±LWR)(38)±GroundLight control switch turned to TAIL or
HEAD (LH±LWR)(40)±GroundHEAD and *ENGINE running
HEAD (RH±UPR)(44)±GroundLight control switch turned to HEAD and
HEAD (LH±UPR)(46)±Grounddimmer switch turned to HI or FLASH
If the circuit is not as specified, refer to BE±15 wiring diagram
and inspect the circuits connected to other parts.
2. INSPECT RELAY CIRCUIT Remove the relay from the relay block and inspect the con-
nector on relay block side as shown.
RelayCheck forTester connectionConditionSpecified value
EFIVoltage(4)±GroundConstantBattery voltage
ST(10)±Ground
(11)±Ground
DIM(15)±GroundLight control switch turned to TAIL or HEAD
(16)±Groundand *Engine running
IG2(18)±GroundConstant
HTR(24)±Ground
(25)±Ground
H±LP(28)±Ground
(30)±Ground
DEF(34)±Ground
(35)±Ground
If the circuit is not as specified, refer to BE±15 wiring diagram
and inspect circuits connected to other parts.
BE±22
±
BODY ELECTRICAL SYSTEM Power Source
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ANTI±LOCK BRAKE SYSTEM (ABS)
BR0EU±04
DESCRIPTION

ABS is a brake system which controls the brake cylinder hydraulic pressure \
to all 4 wheels during sudden
braking and braking on slippery road surfaces, preventing the wheels from locki\
ng. ABS provides the
following benefits:
(1) Enables steering round an obstacle with a greater degree of certai\
nty even when panic braking.
(2) Enables stopping during panic braking while keeping the effect upon stability and steerability to a mini-
mum, even on curves.

In case a malfunction occurs, a diagnosis function and fail±safe system have been adopted for the ABS.
SYSTEM PARTS LOCATION
BR02L±05
BR±52±
BRAKE SYSTEM ANTI±LOCK BRAKE SYSTEM (ABS)
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ON±VEHICLE INSPECTION
1. INSPECT BATTERY SPECIFIC GRAVITY ANDELECTROLYTE LEVEL
(a) Check the specific gravity of each cell.
Standard specific gravity:
1.27±1.29 when fully charged at 20 5C (68 5F)
If gravity is less than specification, charge the battery.
(b) Check the electrolyte quantity of each cell.
If insufficient, refill with distilled (or purified) water.
HINT: Check the indicator as shown in the illustration.
2. CHECK BATTERY TERMINALS, FUSIBLE LINKS AND FUSES
(a) Check that the battery terminals are not loose orcorroded.
(b) Check the fusible links and fuses for continuity.
H±fuse: ALT 150A AM1 100A
AM2 30A
M±fuse: IG SW 40A
Fuse: IGN 7.5A ENGINE 7.5A
INJ 30A
3. INSPECT DRIVE BELTHINT: A belt tensioner is used, so checking the belt tension
is not necessary.
(a) Visually check the drive belt for excessive wear, frayedcords, etc.
If necessary, replace the drive belt.
HINT:
w Cracks on rib side of a drive belt are considered
acceptable. If the drive belt has chunks missing from the
ribs, it should be replaced.
w The drive belt tension can be released by turning the
belt tensioner counterclockwise. The pulley bolt for the
belt tensioner has a left±hand thread.
±
CHARGING SYSTEM On±Vehicle InspectionCH±5
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CodeMaterial
name Heat*
resistant
temperature
limit
°C (°F) Resistance to
alcohol or gasoline Notes
PMMA Polymethyl
Methacrylate 80
(176) Alcohol is harmless if applied only
for short time in small amounts.
Avoid dipping or immers-
ing in alcohol, gasoline,
solvents, etc.
POM Polyoxymethylene
(Polyacetal) 100
(212) Alcohol and gasoline are
harmless.
Most solvents are
harmless.
PP Polypropylene 80
(176) Alcohol and gasoline are
harmless.
Most solvents are
harmless.
PPO Modified
Polyphenylene
Oxide
100
(212) Alcohol is harmless. Gasoline is harmless if
applied only for quick
wiping to remove
grease.
PS Polystyrene 60
(140) Alcohol and gasoline are harm-
less if applied only for short time
in small amounts. Avoid dipping or immers-
ing in alcohol, gasoline,
solvents, etc.
PUR Polyurethane 80
(176) Alcohol is harmless if applied only for
very short time in small amounts (e.g.,
quick wiping to remove grease).
Avoid dipping or immers-
ing in alcohol, gasoline,
solvents, etc.
PVC Polyvinylchloride
(Vinyl) 80
(176) Alcohol and gasoline are harmless if
applied only for short time in small
amounts (e.g., quick wiping to remove
grease). Avoid dipping or immers-
ing in alcohol, gasoline,
solvents, etc.
SAN Styrene
Acrylonitrile 80
(176) Alcohol is harmless if applied only
for short time in small amounts
(e.g., quick wiping to remove
grease).
Avoid dipping or immers-
ing in alcohol, gasoline,
solvents, etc.
SMC Sheet
Moulding
Compound
180
(356) Alcohol and gasoline are
harmless.
Avoid alkali
TPO Thermoplastic
Olefine 80
(176) Alcohol is harmless.
Gasoline is harmless if applied only
for short time in small amounts.
Most solvents are harm-
less but avoid dipping in
gasoline, solvents, etc.
TPU Thermoplastic
Polyurethane 80
(176) Alcohol is harmless if applied only for
very short time in small amounts (e.g.,
quick wiping to remove grease).
Avoid dipping or immers-
ing in alcohol, gasoline,
solvents, etc.
UP Unsaturated
Polyester 11 0
(233) Alcohol and gasoline are
harmless.
Avoid alkali
* Temperatures higher than those listed here may result in material deforma\
tion during repair.
PLASTIC BODY PARTSPP-3
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Butt Weld
INSTALLATION
Butt Weld
1. Temporarily install the new parts and check thefit of the front door.
BODY PANEL REPLACEMENTRE-33
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FOAMED MATERIAL APPLICATION AREAS
The sections shown in the figure below are
filled with foamed material to provide noise
insullation.
After repairing these sections or their periph-
eries, refill with foamed material.
HINT:1. Use the service holes located on the reverse side of the body panel to refillwith foamed material.
2. When handling foamed material, follow the directions of the material's manufac-
turer.
APPENDIXAP-4
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1. Before temporarily installing the new parts,apply body seater to the wheel arch.
HINT:
1) Apply body sealer about 5 mm (0.20 in.) from the flange, avoiding any oozing.
2) Apply sealer evenly, about 3 - 4 mm (0.12 - 0.16 in.) in diameter.
3) For other sealing points, refer to section AR.
RE 42 BODY PANEL REPLACEMENT-Rear Body Components
INSTALLATION
Butt Weld
Body Sealer
Butt Weld
Body Sealer
about 5 mm
2. Temporarily install the new parts and check thefit of the front door, luggage compartment door
and rear combination light.
3. Apply foamed material to the pillar section.
HINT: For the foamed material application areas, refer to page AP-00.
INSTALLATION DIAGRAM
Describes in detail installation of the new parts involving repair by we\
lding and/or cutting,
but excluding painting.
INSTALLATION GUIDE
Provides additional information to more efficiently help you perform the installation.
SYMBOLS
See page IN-4.
ILLUSTRATION OF WELD POINTS
Weld method and panel position symbols.
See page IN-5.
INTRODUCTIONIN-3
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INSTALLATION
PRE-WELDING MEASUREMENTS
Always take measurements
before installing underbody
or engine components
to insure correct assembly.
After installation, confirm
proper fit.POST-WELDING REFINISH-
ING
1. Always check the welded
spots to insure they are
secure.
2. When smoothing out the weld spots with a disc
grinder, be careful not to
grind off too much as this
would weaken the weld.
WELDING PRECAUTIONS
1. The number of welding spots
should be as follows.
Spot weld: 1.3 x No. of
manufacturer's spots.
Plug weld: More than No. of
manufacturer's plugs.
WRONG
OKAYWRONG
2. Plug welding should be done
with a MIG (Metal Inert Gas)
welder. Do not gas weld or
braze panels at areas other
than specified.
Safety Glass
Body
Measurement
Diagrams
SPOT WELDING PRECAUTIONS
SPOT WELD LOCATIONS
Try to avoid welding over
previous spots. 1. The shape of the welding
tip point has an effect on
the strength of the weld.
2. Always insure that the seams and welding tip are
free of paint.
Old
Spot
Locations New Spot
Locations
Tip Cutter
INTRODUCTIONIN-13
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