lock LEXUS SC400 1991 Service Manual PDF

(c) Check for abnormal noise and vibration.Run at the D position lock±up or O/D gear and check for ab-
normal noise and vibration.
HINT: The check for the cause of abnormal noise and vibra-
tion must be performed very thoroughly care as it could also
be due to loss of balance in the propeller shaft, differential,
torque converter clutch, etc..
(d) Check kick±down operation While running in the D position, 2nd, 3rd and O/D gears,
check to see that the possible kick±down vehicle speed limits
for 2 "1, 3 "2 and O/D "3 kick±downs conform to those indi-
cated on the automatic shift schedule. (See page AT±45)
(e) Check abnormal shock and slip at kick±down.
(f) Check the lock±up mechanism. (1) Drive in D position, O/D gear, at a steady speed (lock±upON) of about 58 km/h (36 mph).
(2) Lightly depress the accelerator pedal and check that the engine RPM does not change abruptly.
If there is a big jump in engine RPM, there is no lock±up.
2. 2 POSITION TEST Shift into the 2 position and fully depress the accelerator ped-
al and check the following points:
(a) Check up±shift operation Check to see that the 1 "2 up±shift takes place and that the
shift point conforms to that shown on the automatic shift
schedule. (See page AT±45)
HINT:
w There is no O/D up±shift and lock±up in the 2 position.
(b) Check engine braking While running in the 2 position and 2nd gear, release the ac-
celerator pedal and check the engine braking effect.
AT±42
±
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5. P POSITION TESTStop the vehicle on a gradient (more than 5
) and after shift-
ing into the P position, release the parking brake. Then check
to see that the parking lock pawl holds the vehicle in place.
AT±44
±
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PWR Mode (Kick±down foot switch deactivated)
Shift positionShifting pointVehicle speed km/h (mph)  Throttle valve fully opened 1"2 67±71 (42±44)  2"3 118±124 (73±77)  3"O/D 179±186 (111±116) 
Dposition
 O/D"3 149±155 (93±96) D position 3"2 95±100 (59±62)  2"1 22±26 (14±16)  Throttle valve fully closed 3"O/D 32±35 (20±22)  O/D"3 23±26 (14±16)  Throttle valve fully opened 1"2 67±71 (42±44) 
2 position
 3"2 106±112 (66±70)  2"1 10±13 (6±8) 
Lposition
 Throttle valve fully opened 3"2 104±109 (65±68) L position 2"1 57±63 (35±39)
LOCK±UP POINT
NORM Mode
 D position km/h (mph) 
Lock±upON
 
Lock±upOFF Throttle valve opening 5% Lock±up ON Lock±up OFF
 *3rd Gear 83±88 (52±55) 77±82 (48±51)
 O/D Gear 56±60 (35±37) 53±57 (33±35)
*: O/D Switch OFF
PWR Mode
D position km/h (mph)Lock±upONLock±upOFF Throttle valve opening 5%Lock±up ONLock±up OFF
 *3rd Gear 83±88 (52±55) 77±82 (48±51)
 O/D Gear 56±60 (35±37) 53±57 (33±35)
*: O/D Switch OFF
HINT:
(1) There is no lock±up in the 2 and L positions.
(2) In the following cases, the lock±up will be released regardless\
of the lock±up pattern.

When the throttle valve is completely closed.

When the brake light switch is ON.
(3) Shift up to 3rd will not occur when the engine coolant temp. is below 3\
5 C (95 F) and the vehicle speed
is below 40 km/h (25 mph).
(4) Shift±up to O/D will not occur when the engine coolant temp. is\
below 60 C (140 F) and the vehicle
speed is below 63 km/h (39 mph).
(5) During cruise control operation, the shift pattern is fixed in NOR\
M. And when the vehicle speed drops to 10 km/h (6 mph) or more below the cruise control set vehicle speed, s\
hift down from O/D to 3rd
occurs.
(6) The kick±down foot switch turns ON when the accelerator pedal i\
s depressed further with the throttle valve already fully open.
AT±46
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MANUAL SHIFTING TEST
AT0QV±01
HINT: With this test, it can be determined whether the trouble
is within the electrical circuit or is a mechanical problem in the
transmission.
1. DISCONNECT SOLENOID WIRE
2. INSPECT MANUAL DRIVING OPERATION Check that the shift and gear positions correspond with the
table below.
 Shift Position Gear Position
 D PositionO/D 2 Position3rd L Position1st 

R PositionReverse
 P PositionPawl Lock
HINT: If the L, 2 and D position gear positions are difficult to
distinguish, perform the following road test.
w
While driving, shift through the L, 2 and D positions.
Check that the gear change corresponds to the shift
position.
If any abnormality is found in the above test, the problem is
in the transmission itself.
3. CONNECT SOLENOID WIRE
4. CANCEL OUT DIAGNOSTIC TROUBLE CODE (See page AT±39)
±
A304E (1UZ±FE) AUTOMATIC TRANSMISSION TROUBLESHOOTINGAT±59
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DTC61No.2 Vehicle Speed Sensor Circuit
CIRCUIT DESCRIPTION
The No.2 speed sensor detects the rotation speed of the transmission output shaft and sends signals to the
ECM. The ECM determines the vehicle speed based on the these signals. An AC voltage i\
s generated in the
No.2 vehicle speed sensor coil as the rotor mounted on the output shaft rota\
tes, and this voltage is sent to the
ECM.
The gear shift point and lock±up timing are controlled by the ECM based \
on the signals from this vehicle speed
sensor and the throttle position sensor signal.
If the No.2 vehicle speed sensor malfunctions, the ECM uses input signals \
from the No.1 vehicle speed sensor
as a back±up signal.
DTC No.DTC Detecting ConditionTrouble Area
61
All conditions below are detected 500 times or more
continuously.
2 trip detection logic*
(a) No No.2 vehicle speed sensor signal in 4 No.1 ve-
hicle speed sensor signal pulses.
(b) Vehicle speed: 5.6 MPH (9 km/h) or more for
at least 4 secs.
(c) Park/neutral position switch:
OFF (Other than P or N position)

No. 2 vehicle speed sensor

Harness or connector between No.2 vehicle
speed sensor and ECM.

ECM
*: See page AT±62
Reference

Waveform between terminals SP2+ and SP2± when vehicle speed is approx.\
37 MPH (60km/h).
AT±86
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DTC62, 63No. 1, No. 2 Solenoid Valve Circuit
CIRCUIT DESCRIPTION
Shifting from 1st to O/D is performed in combination with ON and OFF of the No. \
1 and No. 2 solenoid valves
controlled by ECM. If an open or short circuit occurs in either of the solenoid valves\
, the ECM controls the remain-
ing normal solenoid to allow the vehicle to be operated smoothly (Fail saf\
e function.
Fail Safe Function
If either of the solenoid valve circuits develops a short or an open, th\
e ECM turns the other solenoid ON and
OFF to shift to the gear positions shown in the table below. The ECM also turns the lock±up solenoid valve OFF
at the same time. If both solenoids malfunction, Hydraulic control cannot \
be performed electronically and must
be done manually.
Manual shifting as shown in the following table must be done. (In the case of \
a short circuit, the ECM stops send-
ing current to the short circuited solenoid).
 

Position
 

NORMAL
 

NO. 1 SOLENOID
MALFUNCTIONING 

NO. 2 SOLENOID
MALFUNCTIONING 

BOTH SOLENOIDS
MALFUNCTIONING
 Position Solenoid valve Gear Solenoid valve Gear Solenoid valve Gear Gear when shift selectoris
  No. 1 No. 2 Gear No. 1 No. 2 Gear No. 1 No. 2 Gear 
Gear when shift selectorismanually operated
  ON OFF 1st x ON 3rd ON x 1st O/D
 D ON ON 2nd x ON 3rd OFF x O/D O/D
  OFF ON 3rd x ON 3rd OFF x O/D O/D
  OFF OFF O/D x OFF O/D OFF x O/D O/D
  ON OFF 1st x ON 3rd ON x 1st 3rd
 2 (S) ON ON 2nd x ON 3rd OFF x 3rd 3rd

()
OFFON3rdxON3rdOFFx3rd3rd 
L
 ON OFF 1st x OFF 1st ON x 1st 1st L ON ON 2nd x ON 2nd ON x 1st 1st
x: Malfunctions
Check the No. 1 solenoid when diagnostic trouble code 62 is output and check t\
he No. 2 solenoid when diagnos-
tic trouble code 63 is output.
DTC No.DTC Detecting ConditionTrouble Area
62, 63

Solenoid resistance of 8
or less is detected (*)
8 times or more when solenoid is energized.

Solenoid resist ance of 100 k
or more is detected
(*) 8 times or more when solenoid is not energized.
Solenoid valve.

Harness or connector between solenoid and
ECM.

ECM
(*) If the above failures are detected less than 8 times, the ECM memo\
rizes the malfunction code but the O/D
OFF indicator light doesn't blink. AT±90
±
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DTC64No. 3 Solenoid Valve Circuit
(For Lock±up Control Pressure Modulation)
CIRCUIT DESCRIPTION
The No. 3 solenoid valve is provided for lock±up operations.
The lock±up operation pressure is controlled by the linear sole-
noid for smooth engagement.
The amount of current flow to the solenoid is controlled by the
duty ratio (See page AT±82) of ECM output signal. The higher
the duty ration becomes, the higher the lock±up hydraulic pres-
sure becomes during the lock±up operation. If the malfunction
occurs in this circuit and diagnostic trouble code 64 is stored in
memory, the O/D OFF indicator light does not blink.
DTC No.DTC Detecting ConditionTrouble Area
64
All conditions below are detected for 1 sec. or more.
2 trip detection logic*
(a) ECM outputs duty signal to No. 3 solenoid in 90%
or higher duty ration.
(b) Current to No. 3 solenoid: 450
100 mA or less.
 No. 3 solenoid valve
 Harness or connector between No. 3 sole-
noid valve and ECM.
 ECM
*: See page AT±62
Reference
 Waveform between terminals SLU± and E
1 when lock±up function is not operated.
Reference
 Waveform between terminals SLU± and E
1 when lock±up function is operated.
AT±94±
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AT±66BE
IN±33
WIRING DIAGRAM
Stop Light Switch Circuit
CIRCUIT DESCRIPTION
The purpose of this circuit is to prevent the engine from stalling, while d\
riving in lockup condition, when
brakes are suddenly applied.When the brake pedal is operated, this switch sends a signal to ECM. Then
the ECM cancels operation of the lockup clutch while braking is in progress\
.
DIAGNOSTIC CHARTDIAGNOSTIC CHART
AT±108±
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AT±66
IN±33
WIRING DIAGRAM
Pattern Select Switch Circuit
CIRCUIT DESCRIPTION
The ECM memory contains the shift programs for the NORMAL and POWER pattern\
s, 2 position and L
position and the lock±up patterns. Following the programs corresponding to the\
signals from the pattern
select switch, the park/neutral position switch and other various sensor\
s the ECM switches the solenoid
valves ON and OFF, thereby controlling the transmission gear change and the lock±up cl\
utch operation.
DIAGNOSTIC CHARTDIAGNOSTIC CHART
AT±110±
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SERVICE SPECIFICATIONS
SERVICE DATA
AT0GH±02 Line pressure (wheel locked)\
 \

 \
 \
382±441 kPa 3.9±4.5 kgf/cm255±64 psi
 Engine idling D position\
 \

 \
 \
637±716 kPa 6.5±7.3 kgf/cm292±104 psi
 R position\
 \

\
1,265±1,402 kPa 12.9±14.3 kgf/cm2183±203 psi AT stall (Throttle valve opened) D position\
 \

 \
 \
1,726±2,060 kPa 17.6±21.0 kgf/cm2250±298 psi R position\
 \

 ECM SLN termina lNot ground\
 \
177±255 kpa 1.8±2.6 kgf/cm226±37 psi
 Ground\
 \
0
 Engine stall revolution\
 \
2,200+150 RPM
 Time lag N position " D position\
 \
Less than 1.2 seconds
 N position " R position\
 \
Less than 1.5 seconds
 Engine idle speed (Cooling fan and A/C OFF
)N position\
 \
650 RPM
 \
 \
Boot end face and inner cable stopper Throttle cable adjustment (Throttle valve fully closed)\
 \

 \
 \
0±1 mm 0±0.04 in.
 Torque converter clutch installing (Correct distance)\
 \
17.1mm 0.673 in.
 Drive plate runout Limit\
 \
0.20 mm 0.0079 in.
SHIFT POINT (Kick±down foot switch activated)
 Shift position Shifting point Vehicle speed km/h (mph)2
  Throttle valve fully opened 1"2 67±71 (42±44)
  2" 3 118±124 (73±77)
  3" O/D (NORM) 170±177 (106±110)
  3" O/D (PWR) 179±186 (111±116)
 D position (NORM or PWR) O/D "3 164±170 (102±106)
  3" 2 105±111 (65±69)  2" 1 53±57 (33±35) 

2 iti
 

Throttle valve fully opened 1
"2
 

67±71 (42±44)
 2 position
(NORM or PWR) 3
" 2 106±112 (66±70)
 
(NORM or PWR)
 2" 1 53±57 (33±35)
 L position Throttle valve fully opened 3 "2 104±109 (65±68)
 
L osition
(NORM or PWR) 2" 1 57±63 (35±39)
±
A340E (1UZ±FE) AUTOMATIC TRANSMISSION SERVICE SPECIFICATIONSAT±121
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