1991 LEXUS SC400 wiring

18. INSPECT SRS AIRBAGDriver Airbag:
Visually inspect the steering wheel pad (airbag and inflater).
wUse the diagnosis check to check if there are
abnormalities.
w Check that there are no cuts, cracks or noticeable color
changes on the surface of the steering wheel pad or in
the center groove of the pad.
w Remove the steering wheel pad from the vehicle and
check the wiring and steering wheel for damage and
corrosion due to rusting, etc.
If necessary, replace the steering wheel pad.
Front Passenger Airbag:
Visually inspect the front passenger airbag assembly (airbag
and inflater).
w Use the diagnosis check to check if there are
abnormalities.
w Check that there are no cuts, cracks or noticeable color
changes in the front passenger airbag door.
w Remove the front passenger airbag assembly from the
vehicle and check the wiring and front passenger airbag
door for damage and corrosion due to rusting, etc.
If necessary, replace the front passenger airbag assembly.
CAUTION:
w For removal and replacement of the steering wheel pad
or front passenger airbag assembly, see page RS±28 and
be sure to perform the operation in the correct order.
w Before disposing of the steering wheel pad or front
passenger airbag assembly must first be deployed by
using SST and wiring harness connector (See page
RS±28 ).
19. INSPECT STEERING GEAR HOUSING OIL
Check the steering gear housing for oil leakage.
MA±14
±
MAINTENANCE (1UZ ± FE)
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IDLE AND/OR 2,500 RPM HC/CO
CONCENTRATION CHECK METHOD
HINT: This check is used only to determine whether or not the
idle HC/CO complies with regulations.
1. INTIAL CONDITIONS (a) Engine at normal operating temperature.
(b) Air cleaner installed.
(c) All pipes and hoses of air induction system connected.
(d) All accessories switched OFF.
(e) All vacuum lines properly connected.
HINT: All vacuum hoses for EGR systems, etc. should be
properly connected.
(f) EFI system wiring connectors fully plugged.
(g) Transmission in neutral range.
(h) Tachometer and HC/CO meter calibrated at hand.
2. START ENGINE
3. RACE ENGINE AT 2,500 PRM FOR APPROX. 120 SECONDS
4. INSERT HC/CO METER TESTING PROBE INTO TAILPIPE AT LEAST 40 cm (1.3 ft)
5. CHECK HC/CO CONCENTRATION AT IDLE AND/OR 2,500 PRM
Complete the measuring within three times.
HINT: When performing the 2 mode (2,500 rpm and idle) test,
follow the measurement order prescribed by the regulations.
If the HC/CO concentration at 2,500 rpm does not comply
with regulations, try the following procedure.
Race the engine again at 2,500 rpm for approx. 1 minute and
quickly repeat steps 4 and 5 above.
This may correct the problem.
EM±28
±
ENGINE MECHANICAL Idle and/or 2,500 rpm HC/CO
Concentration Check Method
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35. DISCONNECT TRANSMISSION CONTROL RODRemove the nut, and disconnect the control rod from the shift
lever.
36. REMOVE ENGINE AND TRANSMISSION A SSEMBLY
FROM VEHICLE
(a) Attach the engine hoist chain to the engine hangers.
(b) Remove the two nuts holding the engine mounting insulators to the front suspension crossmember.
(c) Remove the four bolts, four nuts and rear engine mounting member. Disconnect the ground strap.
(d) Lift the engine out of the vehicle slowly and carefully.
NOTICE: Be careful not to hit the PS gear housing, neu-
tral start switch and ABS actuator.
(e) Make sure the engine is clear of all wiring, hoses and cables.
(f) Place the engine and transmission assembly onto the stand.
EM±128
±
ENGINE MECHANICAL Cylinder Block
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If there is no pressure, check the following parts:w Fuses
w EFI main relay
w Fuel pump ECU
w Fuel pump
w Engine & ECT ECU
w Wiring connections
2. CHECK FUEL PRESSURE (a) Check the battery voltage above 12 volts.
(b) Disconnect the cable from the negative (±) terminal ofthe battery.
CAUTION: Work must be started after approx. 20 se-
conds or longer from the time the ignition switch is
turned to the ºLOCKº position and negative (±) terminal
cable is disconnected from the battery.
(c) (Exc. USA Spec.) Remove the filter from the VSV (for EGR system).
(d) Remove the union bolt holding the LH deliver pipe to the
rear fuel pipe. Remove the two gaskets.
HINT:
w Put a suitable container or shop towel under the cold
start injector pipe.
w Slowly loosen the union bolt.
(e) Install the rear fuel pipe and SST (pressure gauge) to the LH delivery pipe with three new gaskets and the
union bolt.
SST 09268±45012
Torque: 39 N Vm (400 kgf Vcm, 29 ft Vlbf)
(f) Wipe off any splattered gasoline.
(g) (Exc. USA Spec.)
Reinstall the filter to the VSV.
(h) Using SST, connect terminals B and FP of the check (ºDIAGNOSISº) connector.
SST 09843±18020
(i) Reconnect the cable to the negative (±) terminal of the
battery.
FI±18
EFI SYSTEM
± Fuel System (Fuel Pump)
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Idle Speed Control (ISC) Valve
ON±VEHICLE INSPECTION
INSPECT ISC VALVE FOR OPERATING SOUNDCheck that there is a clicking sound immediately after stop-
ping the engine.
If the rpm operation is not as specified, check the ISC valve,
wiring and ECU.
FI±80
± Air Induction System (Idle Speed Control (ISC\
) Valve)EFI SYSTEM
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4. REMOVE CUP HOLDERUsing a screwdriver, pry out the rear side of the cup holder.
Remove the cup holder.
5. REMOVE UPPER REAR CONSOLE PANEL Using a screwdriver, pry out the console panel.
6. REMOVE UPPER CONSOLE PANEL (a) Remove the six mounting screws.
(b) Using a screwdriver, pry out the console panel.
7. REMOVE RADIO (a) Remove the five mounting bolts.
(b) Disconnect the wiring connectors and antenna cable,
and remove the radio.
8. DISCONNECT SUB±OXYGEN SENSOR CONNECTORS FI±119
EFI SYSTEM
± Electronic Control System (Sub±Oxygen Sensors)
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9. INSPECT HEATER RESISTANCE OF SUB±OXYGEN
SENSORS
Using an ohmmeter, measure the resistance between the ter-
minals +B and HT.
Resistance: 5.1±6.3
at 20 °C (68 °F)
If the resistance is not as specified, replace the sensor as
follows:
w Disconnect the grommet from the floor panel, and
pull out the wire of the sub±oxygen sensor from the
floor panel.
w Remove the sub±oxygen sensor.
w Install a new sub±oxygen sensor.
Torque: 44 N Vm (450 kgf Vcm, 33 ft Vlbf)
w Run the wire of the sub±oxygen sensor through the
hole in the floor panel.
10. RECONNECT SUB±OXYGEN SENSOR CONNECTORS
11. REINSTALL RADIO (a) Connect the wiring connectors and antenna cable.
(b) Install the radio with the five bolts.
12. REINSTALL UPPER REAR CONSOLE PANEL (a) Fit the console panel to the console box with five clips.
(b) Install the console panel with the six screws.
FI±120
EFI SYSTEM
± Electronic Control System (Sub±Oxygen Sensors)
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5. INSPECT FUEL PUMP ECU(a) Connect the cable to the negative (±) terminal of thebattery.
(b) Check the connector on the wiring harness side as shown in the chart.
Check forTester connectionConditionSpecified value
ContinuityE ± Ground±Continuity
ContinuityDI ± Ground±Continuity
VoltageFP GroundSudden racing12 ± 14 VVoltageFP ± GroundIdling8 ± 10 V
Voltage+ B ± GroundIG SW ON10 ± 14 V
VoltageFPC ± Ground
Sudden racing
(1,600 rpm or more)4 ± 6 VVoltageFPC Ground
Idling2.5 V
If circuit is as specified, replace the fuel pump ECU.
(c) Disconnect the cable from the negative (±) terminal of the battery.
6. RECONNECT FUEL PUMP ECU CONNECTOR
7. INSTALL QUARTER TRIM (a) Attach the upper side of the quarter trim to the quarterpanel.
(b) Install the quarter trim with the four clips.
FI±124
EFI SYSTEM
± Electronic Control System (Fuel Pump ECU)
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