1991 LEXUS SC400 relay

OKNG
OKNG
8Check EFI main relay.
C
OK
P
OK
C
Remove EFI main relay.
Check continuity between terminals of EFI main relay
shown below.
1. Apply battery positive voltage between terminals 1and 3.
2. Check continuity between terminals 2 and 4.
Replace EFI main relay.
9Check for open and short in harness and connector between terminal M±REL of\
engine (& ECT)
ECU and body ground (See page IN±27).
Repair or replace harness or connector.
Check and repair harness or connector between
EFI fuse and battery.
±
ENGINE TROUBLESHOOTING Circuit InspectionTR±125
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Neutral Start Switch Circuit
CIRCUIT DESCRIPTION
The neutral start switch goes on when the shift lever is in the N or P shif\
t position. When it goes on the terminal
NSW of the ECU is grounded to body ground via the starter relay and theft deterrent ECU\
, thus the terminal
NSW voltage becomes 0V. When the shift lever is in the D, 2, L or R position, the neutral start\
switch goes off,
so the voltage of ECU terminal NSW becomes battery voltage, the voltage of the ECU internal power source.
If the shift lever is moved from the N range to the D range, this signal\
is used for air±fuel ratio correction and
for idle speed control (estimated control), etc.
When the neutral start switch is off, code º51º is output in the test mode diagnosis. (This is not a\
bnormal.)
DIAGNOSTIC CHARTDIAGNOSTIC CHART
HINT: This diagnosis chart is based on premise that the engine is cranked norm\
ally. If the engine is notcranked, proceed to the matrix chart of problem symptoms on page TR±35.
Check output condition of diag. code 51.
Proceed to next circuit inspection shown
on matrix chart (See page TR±35).
Check for open in harness and connector
between neutral start switch and ECU.
Repair or replace harness or connector.
Check and replace ECU.
Check and replace ECU.
Replace neutral start switch.Check neutral start switch (See page
AT±100 ).
TR±122
±
ENGINE TROUBLESHOOTING Circuit Inspection
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11 8
WIRELESS DOOR LOCK REMOTE CONTROL
7 6 10 542931
2 1
2
1E
11
1D
84
1J
1
1B
5
1I
64
1H
13
1D10 3E
7
3A 6
2
3
BY17
IP 1 20
BX1
2 BX1 11 BX1 8 BX19BX116 BX1 15 BX1 3
I8
I15
I7
B4 B7
9
10
6 3 6
3
BL IF IJ IP1
15
E KSW DSW D L1 LSWD1
UL1 LSWD2 LSWP
P±B
W±L
G± W
G±Y
L±W
W±B
W±B
W±B
W±B
W±B G±L
R±L
R
R
R
R±L
P±B
W±L L±W
G±W G±Y
G±W L±W G±Y
G±Y
G±W G±L
R±W Y
G±LY
W±B
G±L
R±W
R±W
W±B
W±B
W±B
W±B
W±B W±B
FROM POWER SOURCE SYSTEM
(
SEE PAGE 56 )
10A
DOME
+B
WIRE LES S DOOR LOCK E CU
WIRE LES S DOOR LOCK
MAIN SW
UNLOCK WARNING SW
[IGNITION SW]
DOOR OPEN
DE TE CTION SW LH
DOOR OPEN
DE TE CTION SW RH
INTEGRATION
RELAY DIODE
TO DOOR LOCK
AND UNLOCK SW LH
TO DOOR LOCK
AND UNLOCK SW RH
W8
I15
D10
D11
W7
2
1
4
6 IF2
15
IP 1
19
G±Y
G±W
I15
G±Y
TO DOOR LOCK
AND UNLOCK SW RH
IP1
8
G±Y
G±Y
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120
WIRELESS DOOR LOCK REMOTE CONTROL
DOOR LOCK CONTROL (LOCK AND UNLOCK) IS PERFORMED BY REMOTE CONTROL, WI\
THOUT THE IGNITION KEY INSERTED IN
THE DOOR KEY CYLINDER, USING LOW±POWER RADIO WAVES EMITTED BY A TRANSMITTER BUILT INTO IGNITION KEY.
1. WIRELESS DOOR LOCK OR UNLOCK NORMAL OPERATION
WITH THE WIRELESS DOOR LOCK MAIN SW ON, THE IGNITION KEY NOT INSERTED INTO THE IGNITION KEY CYLINDER (UNLOCK
WARNING SW OFF) AND ALL THE DOORS COMPLETELY CLOSED, WHEN THE SWITCH (TRANSMITTER) ON THE IGNITION KEY IS
PUSHED, THE WIRELESS DOOR LOCK ECU RECEIVES THE ELECTRICAL WAVES FROM THE IGNITION KEY (TRANSMITTER),
CAUSING IT TO OPERATE.
AS A RESULT, THE ECU JUDGES WHETHER THE DOOR IS LOCKED OR UNLOCKED BASED ON THE SIGNAL FROM THE DOOR LOCK
MOTOR, AND SENDS A SIGNAL TO THE DOOR LOCK ECU TO SWITCH THE CONDITION FROM LOCK TO UNLOCK OR VICE VERSA,
CAUSING THE DOOR LOCK MOTOR TO OPERATE (FOR THE CURRENT FLOW DURING LOCK AND UNLOCK REFER TO THE DOOR
LOCK CONTROL SYSTEM.)
2. AUTO LOCK OPERATION
AFTER PUSHING THE IGNITION KEY SWITCH (TRANSMITTER) TO UNLOCK ALL THE DOORS, IF A DOOR IS NOT OPENED WITHIN 30
SECONDS, ALL OF THE DOORS ARE AUTOMATICALLY LOCKED AGAIN.
3. WIRELESS DOOR LOCK STOP FUNCTION
IF A DOOR IS OPEN (DOOR COURTESY SW ON), A SIGNAL IS INPUT FROM THE DOOR OPEN COURTESY SW TO THE WIRELESS
DOOR LOCK ECU, STOPPING WIRELESS DOOR LOCK OR UNLOCK.
IF THE IGNITION KEY IS IN THE IGNITION KEY CYLINDER (UNLOCK WARNING SW ON), THE UNLOCK WARNING SWITCH INPUT A
SIGNAL TO THE WIRELESS DOOR LOCK ECU, STOPPING WIRELESS DOOR LOCK OR UNLOCK.
4. DOOR LOCK MOTOR PROTECTIVE FUNCTION
IF THE DOOR LOCK OR UNLOCK CONDITION DOES NOT CHANGE AFTER WIRELESS DOOR L\
OCK OR UNLOCK OPERATION, THE
DOOR LOCK ECU SENDS CURRENT TEN TIMES TO THE DOOR LOCK MOTOR. IF THE DOOR LOCK CONDITION STILL HAS NOT
CHANGED AS A RESULT THE WIRELESS DOOR LOCK ECU STOPS RECEPTION AND STOPS DOOR LOCK AND UNLOCK FUNCTION.
BY MANUALLY OPERATION THE DOOR LOCK OR UNLOCK, THE STOP CONDITION OF THE WIRELESS DOOR LOCK FUNCTION IS
RELEASED.
D10, D11 DOOR OPEN DETECTION SW LH, RH
3±6 : CLOSED WITH DOOR OPENED
I15 UNLOCK WARNING SW [IGNITION SW]
10±9 : CLOSED WITH IGNITION KEY IN CYLINDER
W 8 WIRELESS DOOR LOCK ECU
1±GROUND: APPROX. 12 VOLTS WITH WIRELESS DOOR LOCK MAIN SW ON
7±GROUND: ALWAYS CONTINUITY
10±GROUND: CONTINUITY WITH EACH DOOR OPENED
6±GROUND: CONTINUITY WITH IGNITION KEY IN CYLINDER
: PARTS LOCATION
CODESEE PAGECODESEE PAGECODESEE PAGE
D1030I1529W 729
D1130T 929W 831
: RELAY BLOCKS
CODESEE PAGERELAY BLOCKS (RELAY BLOCK LOCATION)
219ENGINE COMPARTMENT LEFT
423LEFT KICK PANEL (J/B NO.1 LEFT)
: JUNCTION BLOCK AND WIRE HARNESS CONNECTOR
CODESEE PAGEJUNCTION BLOCK AND WIRE HARNESS (CONNECTOR LOCATION)
1B20ENGINE ROOM MAIN WIRE
1D20FRONT DOOR LH WIRE
1E20INSTRUMENT PANEL WIRE
1H
1I20COWL WIRE1J20COWL WIRE
1K
3A22INSTRUMENT PANEL WIRE3E22INSTRUMENT PANEL WIRE
SYSTEM OUTLINE
SERVICE HINTS
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202
WIPER AND WASHER
IFM
1 2
M 1
23 6 5
+1 B +S
+2
OFF
INT
LOW/MIST
HIGH
WASHER
INT TIME
IE1
4
A
13
A7
A
14 B
17
B8
A
6 IE 1
3
1K
6
1J
1 1H
16
L
R±L L±R
L±W
W±B
G±O L
R±L G±O
L
L
L
L
L±R
L
L±W
W±B
W±B
W±B
WIPER AND WASHER SW
(
W/ WIPER RELAY )
[COMB. SW] FROM POWER SOURCE SYSTEM
(
SEE PAGE 56 )
20A
WIPER
WIPER MOTOR W5
C15 , C 1 6
BA
WASHER
MOTOR W2
WIPER RELAY I7
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203
WITH THE IGNITION SW TURNED ON, THE CURRENT FLOWS TO TERMINAL (A)14 OF THE WIPER AND WASHER SW, TERMINAL 2 OF
THE WASHER MOTOR AND TERMINAL 6 OF THE WIPER MOTOR THROUGH THE WIPER FUSE.
1. LOW SPEED POSITION
WITH WIPER SW TURNED TO LOW POSITION, THE CURRENT FLOWS FROM TERMINAL (A)14 OF THE WIPER AND WASHER SW "
TERMINAL (B)8 " TERMINAL 3 OF THE WIPER MOTOR " TERMINAL 1 " TO GROUND AND CAUSES TO THE WIPER MOTOR TO RUN
AT LOW SPEED.
2. HIGH SPEED POSITION
WITH WIPER SW TURNED TO HIGH POSITION, THE CURRENT FLOWS FROM TERMINAL (A)14 OF THE WIPER AND WASHER SW "
TERMINAL (A)7 " TERMINAL 2 OF THE WIPER MOTOR " TERMINAL 1 " TO GROUND AND CAUSES TO THE WIPER MOTOR TO RUN
AT HIGH SPEED.
3. INT POSITION
WITH WIPER SW TURNED TO INT POSITION, THE RELAY OPERATES AND THE CURRENT WHICH IS CONNECTED BY RELAY
FUNCTION FLOWS FROM TERMINAL (A)14 OF THE WIPER AND WASHER SW " TERMINAL (A)6 " TO GROUND . THIS FLOW OF
CURRENT OPERATES THE INTERMITTENT CIRCUIT AND THE CURRENT FLOWS FROM TERMINAL (A)14 OF THE WIPER AND
WASHER SW " TERMINAL (B)8 " TERMINAL 3 OF THE WIPER MOTOR " TERMINAL 1 " TO GROUND AND FUNCTIONS.
THE INTERMITTENT OPERATION IS CONTROLLED BY A CONDENSER'S CHARGED AND DISCHARGED FUNCTION INST\
ALLED IN
RELAY AND THE INTERMITTENT TIME IS CONTROLLED BY A TIME CONTROL SW TO CHARGE THE CHARGING TIME OF THE
CONDENSER.
4. MIST POSITION
WITH WIPER SW TURNED TO MIST POSITION, THE CURRENT FLOWS FROM TERMINAL (A)14 OF THE WIPER AND WASHER SW "
TERMINAL (B)8 " TERMINAL 3 OF THE WIPER MOTOR " TERMINAL 1 " TO GROUND AND CAUSES TO THE WIPER MOTOR TO RUN
AT LOW SPEED.
5. WASHER CONTINUOUS OPERATION
WITH WASHER SW TURNED TO ON, THE CURRENT FLOWS FROM TERMINAL 2 OF THE WASHER MOTOR " TERMINAL 1 "
TERMINAL (A)13 OF THE WIPER AND WASHER SW " TERMINAL (A)6 " TO GROUND AND CAUSES TO THE WASHER MOTOR TO
RUN. AND WINDOW WASHER IS JET. THIS CAUSES THE CURRENT TO FLOW WASHER CONTINUOUS OPERATION CIRCUIT IN
TERMINAL (A)14 OF THE WIPER AND WASHER SW " TERMINAL (B)8 " TERMINAL 3 OF THE WIPER MOTOR " TERMINAL 1 TO
GROUND AND FUNCTION.
C15(B), C16(A) WIPER AND WASHER SW [COMB. SW]
(A) 6±GROUND : ALWAYS CONTINUITY
(A) 14±GROUND : APPROX. 12 VOLTS WITH IGNITION SW AT ON POSITION
(B) 8±GROUND : APPROX. 12 VOLTS WITH WIPER AND WASHER SW AT LOW OR MIST POSITION
APPROX. 12 VOLTS EVERY APPROX. 1 TO 10 SECONDS INTERMITTENTLY WITH WIPER SW AT INT POSITION
(B) 17±GROUND : APPROX. 12 VOLTS WITH IGNITION SW ON UNLESS WIPER MOTOR AT STOP POSITION
(A) 7±GROUND : APPROX. 12 VOLTS WITH IGNITION SW ON AND AFTER WIPER SW OFF UNTIL WIPER MOTOR STOPS
W 5 WIPER MOTOR
6±5 : CLOSED UNLESS WIPER MOTOR AT STOP POSITION
SYSTEM OUTLINE
SERVICE HINTS
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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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144
ABS (ANTI±LOCK BRAKE SYSTEM)
M
A
11
MR A
4
R± A
5
SR
A
6 SFL
A
12 SRR
A
8 AST
A
9 MT
B
1 SFR
B
16 PKB
B
2 GND
B
13 GND
B
1B 4 B
3B 2B5
A 4
A 3
A 1 2 1
IG1
19
IO1
5IO1 7
EB EA 16 22 23 11
EB1
6IK1 10
IJ
EA 1
34
3 2
16
1
4
2
IK2
25 IK2 2
IE1
1
IE2
12
2 1
E10
I23I25
E9
2
6 6
666
66
66
6
B
10
WA
B
6
TS
5
6
E12 L
P±B
V±Y
L±W
L±W L
W
V±YL
W± B L±W V±YY±L
R
R
R
B±R
B±R
B±R
P±B
V
L
L
L V
L V±Y
V
R±Y
Y
B±Y P
L±W Y±G
R±W R±W
W±B
W±B
R±W
R±W
B
B
W±B
W±B W±B
W±B W±B
L±WL
W± B
SFR SFL SRR AST MT
BS
BM
GND WA
TS TC
WB
BATTERY ABS ECU
(
W/O TRACTION CONTROL )
R
120A ALT
60A ABS NO. 1
ABS MOTOR
RELAY
ABS ACTUATOR
RELAY
CHECK
CONNECTOR
FUSE BLOCK
R±W
DIODE
(FOR PARKING BRAKE )
BRAKE FLUID
LEVEL SW
PARKING
BRAKE
SW
ABS ACTUATOR
(
CANA DA )
( USA )
B1
D2
A4 , A33
P3
A2 2
,A23
B
BA A
C3
F9 SHORT PIN
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