ect LEXUS SC300 1991 Service Repair Manual

OKNG
OKNG
6Check voltage between terminal M±REL of engine (& ECT) ECU connector and\
body ground.
C
OK
PTurn ignition switch on.
Measure voltage between terminal M±REL of engine
(& ECT) ECU connector and body ground.
Voltage: 10 ± 14 V
Check and replace engine (& ECT) ECU.
7Check EFI fuse.
C
OK
PRemove EFI fuse from R/B No. 2.
Check continuity of EFI fuse.
Continuity
Check for short in all the harness and components
connected to EFI fuse (See attached wiring diagram).
TR±124
±
ENGINE TROUBLESHOOTING Circuit Inspection
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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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OK
NG
Type I
NG
Type II
NG
OK
OKNG
INSPECTION PROCEDURE
1Check output condition of diag. code 51.
C
P(2) Connect terminals TE2 and E1 of TDCL.
(2) Turn ignition switch on.
(2) Crank the engine.
(2) Connect terminal TE1 and E1 of TDCL.
Check if diagnostic code ª51º is output when then shift
level is in the P and D shift positions.
Result:
Go to step 2.
Go to step 3.
Proceed to next circuit inspection shown on ma-
trix chart (See page TR±35).
2
Check for open in harness and connector between engine & ECT ECU and neutral \
start switch
(See page IN±27).
Check and replace engine & ECT ECU.
Repair or replace harness or connector.
3Check neutral start switch (See page AT±100).
Replace neutral start switch.
Check and replace engine & ECT ECU.
±
ENGINE TROUBLESHOOTING Circuit InspectionTR±123
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VALVE CLEARANCE ADJUSTING TOOL SETPage 1 of 1
The Valve Lifter Press has undergone two modifications that will improve service procedures
on UZ and VZ series engines.
1. Due to space limitations on these engines, the thickness of the valve li\
fter press jaws and its connecting rivet have been reduced. This reduction will allow pr\
oper
compression of the cam follower and spring without the tool slipping out\
of position.
2. The front jaw angle on the valve lifter press has also been modified. Th\
is change will allow easier installation of the tool between the camshaft and the follo\
wer, and also
provide improved leverage for the compression of the cam follower and sp\
ring.
The updated tool set, Part Number 09248±55020, supersedes your previous \
09248±55010
tool set. This new tool set will service all current Lexus engines.
SST'S/SSI'S
001
OCTOBER 11, 1991
ALL MODELS
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TROUBLE SHOOTING:
Use the matrix chart below as a guide to repairs. Verify necessary inputs to the A/C Control Assembly from
the vehicle prior to disassembly. Use the repair manual, A/C system section, to validate such as B+, IL\
L+,
ground, etc.. SUSPECT AREA
SYMPTOM Control Switch Indicator Panel Control Lamp Circuit
Night Illumination does not come on
LCD back lighting does not come on
Indicator lamps of all switches are off
Indicator lamp of all switches are on
LCD is faulty
NOTE: If symptoms still exist after the suspect areas have been tested and fou\
nd not to be
faulty, replace the amplifier.
1LCD illumination bulbs are not serviceable, Control Switch must be repla\
ced if illumination
does not occur.
AIR CONDITIONING CONTROL DISASSEMBLY
:
1. Remove Air Conditioning Control Assembly.
2. Separate Control Panel from case. a. Cut the cloth tape on both sides of the case (See Fig. 2).
1992 - 1995 SC 300/400 A/C CONTROL ASSEMBLY SERVICE PARTS Page 2 of 6
Bulb Switch


1




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1992 - 1995 SC 300/400 A/C CONTROL ASSEMBLY SERVICE PARTSPage 3 of 6
AIR CONDITIONING CONTROL DISASSEMBLY (Cont'd):
b. Remove 2 screws and release the 6 clips to separate the Control Panel from the case.
c. Disconnect 2 connectors to separate the Control Panel from the case.
d. Remove the wire harness (See Fig. 5).
3. Remove Control Switch. a. To replace the Control Switch remove 2 screws and release 4 clips (See Fig. 6).
b. Separate Control Switch from face plate.
4. Replace the Night Illumination Bulb. Using a flat±bladed screwdriver, remove and
replace the Night Illumination Bulb.
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1992 - 1995 SC 300/400 A/C CONTROL ASSEMBLY SERVICE PARTSPage 4 of 6
INSPECTION PROCEDURE:
1. Bulb Circuit:
Bulb Inspection ± Perform the following test
on suspect Night Illumination Bulbs. Check
for continuity as shown. Replace the bulb if
there is no continuity.

Bulb Circuit Inspection ± Verify continuity
between terminals 22 and 24. If there is
no continuity, replace Control Switch.
2. Switch Circuit:
Switch Continuity Inspection ± Check that there
is continuity between the terminals while the
switch is pressed.
If there is no continuity between even one pair
of terminals, replace the Control Switch.
SWITCH
A/C
MODE/R>
MODE/L<
REAR - DEF
FRONT - DEF FRESH
RECIRC OFF
FAN - DOWN FAN - UP 13 - 17
13 - 16
13 - 15
12 - 17
12 - 16
12 - 15
12 - 14
11 - 17
11 - 16
11 - 15
INSPECTION
TERMINALS
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1992 - 1995 SC 300/400 A/C CONTROL ASSEMBLY SERVICE PARTSPage 5 of 6
INSPECTION PROCEDURE (Cont'd):
3. Indicator Lamp Circuit: Connect two 1.5 v dry cell
batteries in series. Using the
table, check that each suspect
indicator lamp illuminates.
NOTE: Since the indicator lamps
are LEDs, do not mix the ª+º
and ª±º terminals of the test
batteries or apply power to
them for more than 3 seconds
at a time.
If a suspect LED does not illuminate
when tested, replace the Control Switch.
INDICATOR
A/C
REAR - DEF
FRONT - DEF FRESH
RECIRC TERMINAL TO
CONNECT ª+º
10
20
20
19
19 TERMINAL TO
CONNECT ª-º
18
18
8
18 8
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TSIB
IntroductionA musty odor may be emitted from the air conditioning system of some vehicles which are
usually operated in areas with high temperature and humidity. It is most noticeable when
the air conditioner is first turned ªONº after the vehicle has bee\
n parked for several hours.
The odor could result from one or more of the following conditions:
1. Blockage of the evaporator housing drain pipe, resulting in the build up of cond\
ensation.
2. Microbial growth in the evaporator, arising from dampness in the evaporator housing
where the cooling air flow is dehumidified.
To address excessive air conditioning evaporator odor, check the evaporator housing drain
pipe for blockage. If no problems are found, the evaporator and housing\
should be cleaned
and disinfected using the general procedure given on page 2, and the model \
specific
procedure on the pages indicated in the Table of Contents at the bottom of this page.
Affected While this procedure may be used on any Lexus vehicle, this bulletin giv\
es details
Vehicles specifically for the '92±'96 ES 300, all GS 300, '93±'94 LS 400, all SC 300/400 and the\
LX 450.
Tools &
PART NUMBER DESCRIPTION OF TOOLS & MATERIALS QUANTITY SOURCE
Materials08821±00810±01 Spray Gun Kit 1 OTC 08821±00811±01 Spray Gun (replacement) (1) OTC
08821±00812±01 Spray Gun Nozzle (replacement) (1) OTC
08821±00813±01 Freshener Mixing Container (replacement) (1) OTC
08821±00801±DS Air Conditioning Freshener 1 per vehicle TMS
CAUTION:
Wear safety glasses, protective mask, and gloves while working with the
freshener.
Warranty
OPCODE DESCRIPTION TIME OPN T1 T2
Information
N/A No applicable warranty information ± ± ± ±
Table ofMODEL PAGE MODEL PAGE MODEL PAGE MODEL PAGE
Contents
ES 300 3 GS 300 5 LS 400 7
GENERAL 2
SC 300 9 SC 400 9 LX 450 11
General Procedure applies to all models and model years.
The Specific Model Sections cover only the listed ªaffected models.º
HEATING & AIR CONDITIONING
September 12, 1997
Title:
AIR CONDITIONING EVAPORATOR ODOR
Models:
'92±96 ES 300, '93±'94 LS 400,
All GS 300, SC 300/400, LX 450.
Page 1 of 11
AC001±97
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