ABS LEXUS SC400 1991 Service Repair Manual

46
POWER SOURCE (Current Flow Chart)*1: USA
*2: CANADA
60
216
226
192178
226 90 144 134 216 102 202
208
212 90
167
A2 A15 C6 B2
B1
A10 A14 A12 A17A13 A23 A24 A25 A32 C11 B3 B4 B6 C3 C10C7
A21
Blower Resistor Auto Antenna Motor
And Relay A/C Magnetic Clutch
Alternator
A/C Control Assembly
A/C Power Transistor
A/T Indicator Light
(for Shift Lever) A/C Control SW and
Radio SWABS ECU
ABS and Traction ECUBrake Fluid Level SW
Blower Motor
Center Airbag Assembly Check Connector
Cornering Light LH
Cigarette Lighter Back±Up Light SW Buckle SW LHABS and Traction ECUCornering Light RH
190
226 22690
126
226 10168
134
144
178


* These are the page numbers of the first page on which the related system\
is shown.
The part indicated is located somewhere in the system, not necessarily o\
n the page indicated here. *Page Nos. of
Related Systems
Parts
Code or
Location
CB or Fuse
50A DEFOG
30A DOOR
30A POWER
15A STOP
15A ECU±B
10A MIR±HTR
10A HEATER
20A TURN
20A WIPER
10A GAUGE
15A ECU±IG
7.5A ENGINE
7.5A IGN
15A CIG
7.5A RADIO No.2
15A TAIL
7.5A PANEL
7.5A ST
15A TEL
10A DOME
20A RADIO No.1
25A HAZ±HORN
30A EFI
7.5 ALT SENCING
15A HEAD LH*1
15A HEAD RH*1
15A HEAD LH±LWR*2
15A HEAD RH±LWR*2
15A HEAD LH±UPR
15A HEAD RH±UPR
60A HEATER
7.5A TRAC
15A SEAT±HTR
Location
[LOCATION](1): J/B No. 1 (See page 20)(2): R/B No. 2 (See page 19)(3): R/B No. 4 (See page 23)
20
19 22
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47
216182
216
178
216
129 104 144 10260
90
216 62
68
11 2
148
104
111 200 148 148 190
D1
C16 C24
C15 C19 C23 C22
C12
C13
C14C14
C13
C12
Airbag W arning Light
Charge Warning Light
Dimmer SW [Comb. SW]Cruise Control Indicator Light
[Comb. Meter]A/T Indicator Light
[Comb. Meter]
Combination Meter
Rear Lights Warning Light Turn Signal Indicator Light
[Comb. Meter] High Beam Indicator Light
[Comb. Meter]
Check Engine Warning Light
Open Door Warning Light
Traction Indicator Light
ABS Warning Light
[Comb. Meter] Seat Belt Warning LightABS Warning Light and T raction
Off Indicator Light [Comb. Meter]
Coolant Level Warning LightCruise Control ECU Turn Signal SW
[Comb. SW]
Wiper and Washer SW
[Comb. SW]
Choke Coil
Crutch Start SW
Cruise Control Clutch SW
Diode (for Brake Fluid Level)Light Control SW
[Comb. SW] Horn SW [Comb. SW]Combination MeterCornering Light SW
[Comb. SW]
C12 80
82
216
216 216 98
86
216134
216
216 216 184
216
80
90
102 80
90
102
68
94
134
148
216
(4)
: R/B No. 5 (See page ) 22
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56
POWER SOURCE
AM2 AM1
ACC
IG 1
IG 2
321 6 411
ST1
1B
2
1J 5
1J 6
1J 3
1J 8 1K
13
1K 4
1J
4
1B
4
1J
7 I24
I33
I11 P
N 2
3
IE1
16
IJ16
3421314 59 7
116
W
WB
B
B
B±R
B±W B±W
W±L
B
B±O P±L B
B
B
W±L R
W±R
W±R
B
W±R Y
W±L
W±R
W
W±R
B±Y
B±W P±L
B±O
B±W
B±W
B±W
B±WW
B±R
15A ECU±B
15A STOP
30A POWER
30A DOOR
TAILLIGHT
RELAY 15A TAIL
7. 5A PANEL BATTERY
15A ECU±IG
7. 5A ENGINE
20A W IPER
10A GAUGE 20A TURN
10A HEATER
7. 5A ST
7. 5A IGN 15A CIG
7. 5A RADIO NO. 2
40A
IGSW
NEUTRAL
START SW
TO ENGINE AND ECT ECUTO CRUISE CONTROL ECU
TO ABS ACTUATOR RELAY,
ABS MOTOR RELAY AND
TRACTION BRAKE
ACTUATOR RELAYTO ALTERNATOR º Bº
IGNITION SW
FUSE BLOCK
TO TRACTION MOTOR RELAY100A AM1
60A ABS NO. 1
30A INJ
120A ALT 30A AM2
30A ABS NO. 2 60A MAIN
F9
N1
I15
5
1 3
2
2
6
3 4 1
5
1 2IJ2
8 B
B±W
B
B
(
M/T )
(
M/T )
C23
CLUTCH START SW
(
A/T )
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11
FINDING A SHORT CIRCUIT
(a) Remove the blown fuse and disconnect all loads of thefuse.
(b) Connect a test bulb in place of the fuse.
(c) Establish conditions in which the test bulb comes on.
Example: ± Ignition SW on
± Ignition SW and SW 1 on
± Ignition SW, SW 1 and Relay on (Connect theRelay) and SW 2 off (or Disconnect SW 2)
(d) Disconnect and reconnect the connectors while watching the test bulb.
The short lies between the connector where the test
bulb stays lit and the connector where the bulb goes
out.
(e) Find the exact location of the short by lightly shaking the problem wire along the body.
CAUTION:
(a) Do not open the cover or the case of the ECU unlessabsolutely necessary. (If the IC terminals are touched,
the IC may be destroyed by static electricity.)
(b) When replacing the internal mechanism (ECU part) of the digital meter, be careful that no part of your body or
clothing comes in contact with the terminals of leads
from the IC, etc. of the replacement part (spare part).
DISCONNECTION OF MALE AND FEMALE
CONNECTORS
To pull apart the connectors, pull on the connector itself, not the
wire harness.
HINT: Check to see what kind of connector you are disconnecting
before pulling apart.
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15
ABBREVIATIONS
DISCONNECTION AND CONNECTION OF BOLT
TYPE CONNECTORS
For engine and ECT ECU in this vehicle, connectors are used
which require a bolt built into the connector to be screwed down to
securely connect the connector.
1. Disconnect the connectorAfter completely loosening the bolt, the two parts of the
connector can be separated.
NOTICE:
Do not pull the wire harness when disconnecting the
connector.
2. Connect the connector
NOTICE:
Before connecting the connector, always check that the
terminals are not bent or damaged.
(a) Match the guide section of the male connectorcorrectly with the female connector, then press them
together.
(b) Tighten the bolt. Make sure the connectors are completely connected,
by tightening the bolt until there is a clearance of less
than 1 mm (0.04 in.) between the bottom of male
connector and the end of female connector.
ABBREVIATIONS
The following abbreviations are used in this manual.
A/C = Air Conditioning O/D = Overdrive
ABS = Anti±Lock Brake System R/B = Relay Block
A/T = Automatic Transmission RH = Right±Hand
CB = Circuit Breaker SRS = Supplement Restraint System
COMB. = Combination SW = Switch
ECT = Electronic Controlled Transmission TDCL = Total Diagnostic Communication Link
ECU = Electronic Control Unit TEMP. = Temperature
EGR = Exhaust Gas Recirculation TRAC = Traction Control
FL = Fusible Link VSV = Vacuum Switching Valve
ISC = Idle Speed Control W/ = With
J/B = Junction Block W/O = Without
LH = Left-Hand
* The titles given inside the components are the names of the terminals (ter\
minal codes) and are not treatedas being abbreviations.
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