LEXUS SC400 1991 Service Repair Manual

ECM DATA MONITOR BY USING LEXUS
HAND±HELD TESTER
AT0RE±01
1. Hook up the LEXUS hand±held tester to the DLC2.
2. Monitor the ECM data by following the prompts on thetester screen.
HINT: LEXUS hand±held tester has a ªSnapshotº function
which records the monitored data.
Please refer to the LEXUS hand±held tester operator's
manual for further details.
ECM TERMINAL VALUES
MEASUREMENT BY USING LEXUS
BRAKE±OUT BOX AND LEXUS
HAND±HELD TESTER
AT0RF±01
1. Hook up the LEXUS brake±out box and LEXUShand±held tester to the vehicle.
2. Read the ECM input/output values by following the
prompts on the tester screen.
HINT: LEXUS hand±held tester has a ªSnapshotº function.
This records the measured values and is effective in the diag-
nosis of intermittent problems.
Please refer to the LEXUS hand±held tester/LEXUS brake±
out box operator's manual for further details.
AT±40
±
A304E (1UZ±FE) AUTOMATIC TRANSMISSION TROUBLESHOOTING
WhereEverybodyKnowsYourName

PROBLEM SYMPTOM CONFIRMATION
AT09U±07
Taking into consideration the results of the customer problem analysis, try to\
reproduce the symptoms of
the trouble. If the problem is that the transmission does not up±shift, \
does not down±shift, or the shift point
is too high or too low, conduct the following road test referring to the automatic shift schedu\
le and simulate
the problem symptoms.
ROAD TEST
AT09V±05NOTICE: Perform the test at normal ATF operating temperature
50±80 5C (122±176 5F).
1. D POSITION TEST (NORM AND PWR PATTERN)
Shift into the D position and fully depress the accelerator ped-
al and check the following points:
(a) Check up±shift operation
1" 2, 2 "3 and 3 "O/D up±shift takes place, and shift point
should conform to those shown in the automatic shift sched-
ule (See page AT±45)
Conduct a test under both Normal and Power patterns.
HINT:
w O/D up±shift or lock±up will not occur when the engine
coolant temp. is below 60
C (140
F) and speed is under
60 km/h (37 mph), or if there is a 10 km/h (6 mph)
difference between the set cruise control speed.
w 3rd up±shift or lock±up will not occur when engine
coolant temp. is below 35
C (95
F) and speed is under
40 km/h (25 mph).
(b) Check for shift shock and slip. In the same manner, check the shock and slip at the 1 "2,
2 " 3 and 3 "O/D up±shifts.
±
A304E (1UZ±FE) AUTOMATIC TRANSMISSION TROUBLESHOOTINGAT±41
WhereEverybodyKnowsYourName

(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
±
A304E (1UZ±FE) AUTOMATIC TRANSMISSION TROUBLESHOOTING
WhereEverybodyKnowsYourName

(c) Check for abnormal noise during acceleration anddeceleration, and for shock at up±shift and down±shift.
3. L POSITION TEST Shift into the 2 position and fully depress the accelerator ped-
al and check the following points:
(a) Check no up±shift While running in the L position, check to see that there is no
up±shift to 2nd gear.
(b) Check engine braking While running in the L position, release the accelerator pedal
and check the engine braking effect.
(c) C h e c k f o r a bnormal noise during acceleration and
deceleration.
4. R POSITION TEST Shift into the R position and fully depress the accelerator ped-
al and check for slipping.
CAUTION: Before conducting this test ensure that the test area
is free from personnel and obstructor.
±
A304E (1UZ±FE) AUTOMATIC TRANSMISSION TROUBLESHOOTINGAT±43
WhereEverybodyKnowsYourName

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
±
A304E (1UZ±FE) AUTOMATIC TRANSMISSION TROUBLESHOOTING
WhereEverybodyKnowsYourName

AT09W±09
AUTOMATIC SHIFT SCHEDULE
SHIFT POINT
NORM Mode (Kick±down foot switch activated)
 Shift position Shifting point Vehicle speed km/h (mph)
  Throttle valve fully opened 1"2 67±71 (42±44)
  2"3 118±124 (73±77)
 Dposition 3"O/D 170±177 (106±110)
 
D position
 O/D"3 164±170 (102±106)
  3"2 105±111 (65±69)
  2"1 53±57 (33±35)
  Throttle valve fully opened 1"2 67±71 (42±44)
 2 position 3"2 106±112 (66±70)
  2"1 53±57 (33±35)
 Lposition Throttle valve fully opened 3"2 104±109 (65±68)
 
L position
 2"1 57±63 (35±39)
NORM Mode (Kick±down foot switch deactivated)
 Shift position Shifting point Vehicle speed km/h (mph)  Throttle valve fully opened 1"2 67±71 (42±44)  2"3 118±124 (73±77)  3"O/D 155±161 (96±100) 
Dposition
 O/D"3 128±134 (79±83) D position 3"2 71±75 (44±47)  2"1 10±13 (6±8)  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)
PWR Mode (Kick±down foot switch activated)
 Shift position Shifting point Vehicle speed km/h (mph)  Throttle valve fully opened 1"2 67±71 (42±44)
  2"3 116±124 (73±77)
 
Dposition
 3"O/D 179±186 (111±116)
 D position O/D"3 164±170 (102±106)
  3"2 105±111 (65±69)
  2"1 53±57 (33±35)
  Throttle valve fully opened 1"2 67±71 (42±44)
 2 position 3"2 106±112 (66±70)
  2"1 53±57 (33±35)
 
Lposition
 Throttle valve fully opened 3"2 104±109 (65±68)
 L position 2"1 57±63 (35±39)
±
A304E (1UZ±FE) AUTOMATIC TRANSMISSION TROUBLESHOOTINGAT±45
WhereEverybodyKnowsYourName

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
±
A304E (1UZ±FE) AUTOMATIC TRANSMISSION TROUBLESHOOTING
WhereEverybodyKnowsYourName

AT00S±01
PRELIMINARY CHECK
1. CHECK FLUID LEVELHINT:
wDrive the vehicle so that the engine and transmission
are at normal operating temperature.
Fluid temp.: 70±80 5C (158±176 5F)
w Only use the COOL range on the dipstick as a rough
reference when the fluid is replaced or the engine does
not run.
(a) Park the vehicle on a level surface and set the parking brake.
(b) With the engine idling and the brake pedal depressed, shift the shift lever into all positions from P to L position and return
to P position.
(c) Pull out the transmission dipstick and wipe it clean.
(d) Push it back fully into the tube.
(e) Pull it out and check that the fluid level is in the HOT range. If the level is at the low side, add fluid.
Fluid type:
ATF TYPE T±II or Equivalent
NOTICE: Do not overfill.
2. CHECK FLUID CONDITION If the fluid smells burnt or is black, replace it.
3. REPLACE TRANSMISSION FLUID
(a) Remove the drain plug and drain the fluid.
(b) Reinstall the drain plug securely.
(c) With the engine OFF, add new fluid through the oil filler tube.
Fluid type:
ATF TYPE T±II or Equivalent
Capacity:
Total: 8.2 liters (8.7 US qts, 7.2 lmp. qts)
Drain and refill: 1.9 liters (2.0 US qts, 1.7 lmp. qts)
(d) Start the engine and shift the shift lever into all positions fromP to L position and then shift into P position.
(e) With the engine idling, check the fluid level. Add fluid up to the
COOL level on the dipstick.
±
A304E (1UZ±FE) AUTOMATIC TRANSMISSION TROUBLESHOOTINGAT±47
WhereEverybodyKnowsYourName

(f) Check the fluid level at the normal operating temperature70±80
C (158±176
F) and add as necessary.
NOTICE: Do not overfill.
4. CHECK FLUID LEAKS
Check for leaks in the transmission.
If there are leaks, it is necessary to repair or replace O±rings,
seal packings, oil seals, plugs or other parts.
5. INSPECT AND ADJUST THROTTLE CABLE
(a) Remove the 2 bolts, nut and throttle body cover.
(b) Check that the throttle valve is fully closed.
(c) Check that the inner cable is not slack.
(d) Measure the distance between the outer cable end and stopper on the cable.
Standard distance:
0±1 mm (0±0.04 in.)
If the distance is not standard, adjust the cable by the adjust-
ing nuts.
(e) Install the throttle body cover, and two bolts and nut.
6. INSPECT AND ADJUST SHIFT LEVER POSITION When shifting the shift lever from the N position to other posi-
tions, check that the lever can be shifted smoothly and accu-
rately to each position and that the position indicator correctly
indicates the position.
If the indicator is not aligned with the correct position, carry
out the following adjustment procedures:
(a) Loosen the nut on the control shaft lever.
(b) Push the control shaft lever fully rearward.
(c) Return the control shaft lever 2 notches to N position.
(d) Set the shift lever to N position.
(e) While holding the shift lever lightly toward the R position side,
tighten the shift lever nut.
(f) Start the engine and make sure that the vehicle moves forward when shifting the lever from the N to D position and
reverses when shifting it to the R position.
AT±48
±
A304E (1UZ±FE) AUTOMATIC TRANSMISSION TROUBLESHOOTING
WhereEverybodyKnowsYourName

7. INSPECT AND ADJUST PARK/NEUTRAL POSITION
SWITCH
Check that the engine can be started with the shift lever only
in the N or P position, but not in other positions.
If not as started above, carry out the following adjustment
procedure:
(a) Loosen the park/neutral position switch bolt and set the shift lever to the N position.
(b) Align the groove and neutral basic line.
(c) Hold in position and tighten the bolt.
Torque: 12 N Vm (125 kgf Vcm, 9 ft Vlbf)
For continuity inspection of the park/neutral position switch,
see page AT±106.
8. INSPECT IDLE SPEED
Idle speed:
650 RPM (In N position and air conditioner OFF)
±
A304E (1UZ±FE) AUTOMATIC TRANSMISSION TROUBLESHOOTINGAT±49
WhereEverybodyKnowsYourName