key LEXUS SC400 1991 Service Owner's Manual

OKNG
OKNG
INSPECTION PROCEDURE
1Check door key lock and unlock switch.
C
OK
P1. Remove the door trim and service hole cover.
2. Disconnect the door ley lock and unlock switch con-
nector.
Check continuity between terminals 1, 2 and 3 of door
key lock and unlock switch is turned to the lock side, un-
lock side and not turned.
Replace door key lock and unlock switch.
2Check harness and connectors between ECU ans switch, switch and body ground (See page
IN±27 ).
Repair or replace harness or connector.
Proceed to next circuit inspection shown on ma-
trix chart (See page BE±371).
±
BODY ELECTRICAL SYSTEM Door Lock Control SystemBE±387
WhereEverybodyKnowsYourName

OKOK NG NG
Check key unlock warning switch.
Check harness and connectors between ECU and
key unlock warning switch, key unlock warning
switch and body ground (See page
IN±27).
Replace key unlock warning
switch.1
2
Proceed to next circuit inspection shown on
matrix chart (See page BE±371). Repair or replace harness or
connector.
WIRING DIAGRAM
Key Unlock Warning Switch Circuit
CIRCUIT DESCRIPTION
The key unlock warning switch goes on when the ignition key is inserted in the key cylinder and goes
off when the ignition key is removed.
The ECU operates the key confinement prevention function while the key unlo\
ck warning switch is on.
DIAGNOSTIC CHARTDIAGNOSTIC CHART
BE±388±
BODY ELECTRICAL SYSTEM Door Lock Control System
WhereEverybodyKnowsYourName

OKNG
OKNG
INSPECTION PROCEDURE
1Check key unlock warning switch.
C
OK
PDisconnect key unlock warning switch connector.
Check continuity between terminal 9 and 10 of key un-
lock warning switch connector, when the key is inserted
to the key cylinder or removed.
Replace key unlock warning switch.
2Check harness and connectors between ECU and key unlock warning switch, key un\
lock warn-
ing switch and body ground (See page IN±27).
Repair or replace harness or connector.
Proceed to next circuit inspection shown on ma-
trix chart (See page BE±371).
±
BODY ELECTRICAL SYSTEM Door Lock Control SystemBE±389
WhereEverybodyKnowsYourName

DESCRIPTION
The wireless door lock control system is to lock and unlock all the doors a\
t a distance, transmitting a weak radio
wave from a transmitter contained in the master ignition key.
The weak radio wave (coded differently for each key) is sent to the receiver via the rear window defo\
gger wiring.
For the function of the component parts of this system, refer to the circui\
t description in circuit inspection.
PARTS LOCATION
BE±440±
BODY ELECTRICAL SYSTEM Wireless Door Lock Control System
WhereEverybodyKnowsYourName

DESCRIPTION
The wireless door lock control system is to lock and unlock all the door\
s at a distance, transmitting a weak radio
wave from a transmitter contained in the master ignition key.
The weak radio wave (coded differently for each key) is sent to the receiver via the rear window defo\
gger wiring.
For the function of the component parts of this system, refer to the circui\
t description in circuit inspection.
PARTS LOCATION
BE±440±
BODY ELECTRICAL SYSTEM Wireless Door Lock Control System
WhereEverybodyKnowsYourName

CUSTOMER PROBLEM ANALYSIS CHECK SHEET
\
 
\

\
WIRELESS DOOR LOCK CONTROL System Check Sheet
Inspector 's
Name:
 


 


 

Registration No.
 


 Customer 's Name  Registration Year //
 


 


 

Frame No.
 


 


Date Vehicle
Brought In 

// 

Odometer Reading 


Km
Miles
 Date of Problem Occurrence\
 \
//
 

Frequency of Problem Occurrence
\
 
\

\

Constant  Sometimes ( times/per day, month)
 Once Only
 


Conditions at
 

Weather
\
 
\

\


Fine  Cloudy  Rainy  Snowy
 Various/Others
 


Conditions at
Time of Problem
Occurrence 

Outdoor Temperature
\
 
\

\


Hot  Warm  Cool
 Cold (Approx. 5F( 5C))
 


 

Place\
 
\

\

Everywhere  Specific Locality ( )
 

Date Transmitter Battery Last Replaced\
 
\

\
//
 \
 \

Whole wireless door lock control system does not operate
\

Whole wireless door lock control system does not operate.
 


\
 
\

\

Only door unlock operation is not possible.
 \
 \
Only door lock operation is not possible.
 


\
 
\

\

Only key confine prevention function is not possible.
 \
 \
 Wireless door lock function operates even when each door is opened.
 




\
 
\


\

\


Wireless door lock function incorrectly.
(Although one door is unlocked, when the transmitter
switch is pressed, all doors unlock.)
 





When RH door is unlocked.
 When LH door is unlocked.
 








\
 
\


\


\


\

\


Others
Problem Symptom
BE±444±
BODY ELECTRICAL SYSTEM Wireless Door Lock Control System
WhereEverybodyKnowsYourName

PRECHECK TYPE I
In cases where the wireless door lock control system fails to operate only\
at a specific locality, perform this check
at that locality.
Open the driver's door
(Other doors remain closed).Using the door lock control switch, perform
ªlock, unlockº
*1 operation 10 times within 30
seconds.
How many times in 10 seconds is ªlock, un-
lockº
*1 operation performed automatically by
the ECU?
Noise is being produced at that locality.
*3
Vehicle is now receiving signals from a
transmitter of another vehicle (during
transmission from transmitter of another
vehicle).
Malfunction on vehicle side
(Proceed to Matrix Chart of Problem
Symptom on page
BE±454).
Does not
operate
2 times
3 times
Normal
*2
*1: Performing lock and unlock once counts as one time.
*2: If noise is not constantly produced at the locality being used and inspect\
ion is performed on an occasion when there is no noise, then it may happen that the system is judged normal.\
*3: If the conclusion is that noise is produced in the locality the vehicle is\
used, then transmitter use is limited in that locality. Limitations on usage are described below.
HINT:
Because the transmitter uses weak electromagnetic waves, it is easily affected by noise, so remote control with-
in the normal range becomes difficult.
To reduce the influence of noise, bring the transmitter as close as possib\
le to the back window glass (antenna
section), or touch (ground) the grooved key tip of the transmitter to\
the door key cylinder and then operate the
transmitter switch; this should make door lock remote control operation possible.
If door lock remote control operation is still not possible, insert the \
key in the door key cylinder and press the
transmitter switch.
±
BODY ELECTRICAL SYSTEM Wireless Door Lock Control SystemBE±445
WhereEverybodyKnowsYourName

Open the driver's door
(Other doors remain closed).
Using the door lock control switch, perform
ªlock, unlockº
*1 operation 10 times with in
30 seconds.
Soon (less than 2 secs.) after performing
the above, continue to press the transmitter
switch for 10 seconds. How many times does ªlock, unlockº *1 op-
eration of all doors occur during the time the
transmitter is operated (approx. 10 secs.)? Malfunction on vehicle side
(Proceed to Matrix Chart of Problem
Symptom on page
BE±454).
Wrong transmitter parts (exclusive code
does not match).
[Replace transmitter and ROM in ECU.
(See page BE±449)]
Transmitter fault
(Inspect transmitter on page BE±447).
Close all doors.
Tune the FM radio to 94.9 MHz.
Inspect transmitter (See page BE±447).
Do all doors lock and unlock?
Is there noise on the radio while the trans-
mitter switch is being pushed? *2 Malfunction on antenna curcuit
(Inspect antenna circuit on page
BE±448).
Malfunction on vehicle side
(Proceed to Matrix Chart of Problem
Symptom on page BE±454).
3 times
2 timesDoes not
operate
YESYES
NO
NO Once

Disconnect the antenna cable from the ECU, directly insert
the transmitter (grooved section of key) and press the trans-
mitter switch. In this case do not let the transmitter come in
contact with the ECU case (because the transmitter will be
grounded).
PRECHECK TYPE II
Perform this check in cases where the wireless door lock control system fails t\
o operate anywhere.
*1: Performing lock and unlock once counts as one time.
*2: In some localities, inspection cannot be carried out because the local FM \
radio broadcast is also at 94.9 MHz. When this occurs, perform inspection using a portable radio in a place \
indoors free from the influence
of FM broadcasts.
BE±446
±
BODY ELECTRICAL SYSTEM Wireless Door Lock Control System
WhereEverybodyKnowsYourName

PARTS REPLACEMENT
WIRELESS DOOR LOCK ECU REMOVAL
AND INSTALLATION
1. REMOVE WIRELESS DOOR LOCK ECU(a) Remove the rear seat.
(b) Remove the RH quarter trim panel.
(c) Disconnect the connectors.
(d) Remove the ECU.
2. INSTALL WIRELESS DOOR LOCK ECU For installation, follow the removal procedure in reverse.
WIRELESS DOOR LOCK ECU AND
TRANSMITTER REPLACEMENT
Disassembly and assembly of the wireless door lock ECU
and transmitter includes details of spare parts and replace-
ment procedure for defective parts found through trouble-
shooting.
Each part is a precision electronic component so handle with
care.
Destroy old ROM and transmitter to prevent reuse.
1. SPARE PARTS AND REPLACEMENT PROCEDURE FOR MALFUNCTIONING PARTS
(For malfunctioning transmitter)
(a) Prepare the new transmitter (with ROM).
(b) Remove the ECU from the vehicle.
(c) Remove the ROM from the ECU.
(d) Install the new ROM into the ECU.
(e) Install the ECU into the vehicle.
(f) Check that door lock remote control operation works.
(g) Cut the new key to the shape of the replaced key.
(For non±functioning battery)
(a) Prepare new battery (with O±ring).
(b) Remove battery and O±ring from transmitter.
(c) Install new battery and O±ring into transmitter.
±
BODY ELECTRICAL SYSTEM Wireless Door Lock Control SystemBE±449
WhereEverybodyKnowsYourName

Terminals of ECU
WIRING DIAGRAM
No.SymbolTerminal NameNo.SymbolTerminal Name
W8±1+BPower SourceW8±6KSWKey Unlock Warning Switch
W8±2LSWD1Door Unlock Detection Switch LHW8±7EGround
W8±3LSWPDoor Unlock Detection Switch RHW8±8
W8±4UL1Door Key Lock and Unlock SwitchW8±9LSWD2Door Lock Motor LH
W8±5L1Door Key Lock and Unlock SwitchW8±10DSWDDoor Open Detection Switch
BE±452±
BODY ELECTRICAL SYSTEM Wireless Door Lock Control System
WhereEverybodyKnowsYourName