LEXUS SC400 1991 Service Repair Manual

BE±292
BE±29 4
BE±29 8
BE±30 0
BE±30 2
BE±30 4
BE±30 6
IN±32
See tilt and telescopic section on page SR±28
See tilt and telescopic section on page SR±28
See tilt and telescopic section on page SR±28
HINT:
w
If the instruction ºProceed to next circuit inspection shown on matrix \
chartº is given in the flow chart for each
circuit, proceed to the circuit with the next highest number in the table to con\
tinue the check.
w If the trouble still reappears even though there are no abnormalities in a\
ny of the other circuits, then check
and replace the driver's seat ECU as the last step.
±
BODY ELECTRICAL SYSTEM Power Seat Control System (Driver's Seat)BE±277
WhereEverybodyKnowsYourName

LOCATION OF CONNECTORS
Location of Connectors in Engine Compartment
BE±278±
BODY ELECTRICAL SYSTEM Power Seat Control System (Driver's Seat)
WhereEverybodyKnowsYourName

Location of Connectors in Body
±
BODY ELECTRICAL SYSTEM Power Seat Control System (Driver's Seat)BE±279
WhereEverybodyKnowsYourName

Location of Connectors in Instrument Panel
BE±280±
BODY ELECTRICAL SYSTEM Power Seat Control System (Driver's Seat)
WhereEverybodyKnowsYourName

±
BODY ELECTRICAL SYSTEM Power Seat Control System (Driver's Seat)BE±281
WhereEverybodyKnowsYourName

Location of Connectors in Seat
BE±282±
BODY ELECTRICAL SYSTEM Power Seat Control System (Driver's Seat)
WhereEverybodyKnowsYourName

±
BODY ELECTRICAL SYSTEM Power Seat Control System (Driver's Seat)BE±283
WhereEverybodyKnowsYourName

CIRCUIT INSPECTION
+B Power Source Circuit
CIRCUIT DESCRIPTION
This is the power source for motors such as the slide motor and reclining mo\
tor.
DIAGNOSTIC CHARTDIAGNOSTIC CHART
Check Door fuse.NG
Check for short in all harness and
components connected to the
DOOR fuse (See attached wiring
diagram).
Check voltage between terminals +B, +B2
and GND of ECU connector. OK
OKProceed to next circuit inspection
shown on matrix chart (See page
BE±276
).
Check continuity between terminal GND
of ECU connector and body ground. NG
NGRepair or replace harness or
connector.
OK
Check and repair harness or connector
between ECU and battery.
WIRING DIAGRAM
BE±284±
BODY ELECTRICAL SYSTEM Power Seat Control System (Driver's Seat)
WhereEverybodyKnowsYourName

OKNG
NGOK
OKNG
INSPECTION PROCEDURE
1Check DOOR fuse.
Check for short in all the harness and components con-
nected to the DOOR fuse (See attached wiring diagram).
2Check voltage between terminals +B, +B2 and GND of ECU connector.
C
OK
PRemove ECU with connectors still connected.
Measure voltage between terminals +B, +B2 and GND
of ECU connector.
Voltage: 10 ± 14 V
Proceed to next circuit inspection shown on matrix chart
(See page BE±276.)
3Check continuity between terminal GND of ECU connector and body ground.
C
OK
Measure resistance between terminal GND of ECU and
body ground.
Resistance: 1
or less.
Repair or replace harness or connector.
Check and repair harness or connector between
ECU and battery.
±
BODY ELECTRICAL SYSTEM Power Seat Control System (Driver's Seat)BE±285
WhereEverybodyKnowsYourName

WIRING DIAGRAM
ECU Power Source Circuit
CIRCUIT DESCRIPTION
This circuit provides power for ECU operation and is also the power source f\
or the sensors.
DIAGNOSTIC CHARTDIAGNOSTIC CHART
Check DOME fuse.NGCheck for short in all the harness
and components connected to
DOME fuse.
(See attached wiring diagram).
OK
Check voltage between terminals SYSB
and SGND of ECU connector. Proceed to next circuit inspection
shown on matrix chart
(See page
BE±276).
Check continuity between terminal SGND
of ECU connector and body ground. OK
NG
OK NG
Replace or repair harness or
connector.
Check and repair harness or connector
between ECU and battery.
BE±286±
BODY ELECTRICAL SYSTEM Power Seat Control System (Driver's Seat)
WhereEverybodyKnowsYourName