Toyota ZZT230 series, Repair Manual

Page: 372 / 821

)
)
)
m-1s1
DIAGNOSTICS
AUTOMATIC TRANSAXLE
(b) Clear the DTC.
The following operation will erase the DTC and freeze
frame data. Operating an OBO
II scan tool (complying
with SAE J1 978) or TOYOTA hand-held tester to erase
the codes.
(See the OBD II scan tool's instruction book for operating
instructions.)
NOTICE:
If the TOYOTA hand-held tester switches the ECM
from
Normal mode to Check mode or vice-versa, of If the lgnl·
lion switch Is turned from ON to ACC
or
OFF during chick
mode, the DTCs and freeze frame data
w
i l
l
be
erased.
4.
PROBLEM SYMPTOM CONFIRMATION
Taking into
consideration the results of the customer problem analysis, try to reproduce the symptoms of the
trouble. If the problem is that the transaxle does not up-shift, down-shift, or the shift point is too high or too
low,
conduct
the following road test to confirm the automatic shift schedule and simulate the problem symp­
toms.
5.
ROADTEST
NOTICE:
Perform the test at normal operating ATF temperature
50 - 80
'c
(122 - 176
'F).
(a)
D
position test
Shift into
the
0 position and fully depress the accelerator pedal and check the following points.
(1) Check up-shift operation.
Check to see that 1
�
2, 2
�
3 and 3 --t OlD up-shift takes place, and that the shift points con­
form to the automatic shift schedule (See page SS--41 ).
HINT:
•
OlD
Gear Up-shift Prohibition Control ( 1 . Coolant temp. is 60 "C (140 "F) or less. 2.
If
there is a 1 0
kmlh (6
mph) difference between the set cruise control speed and vehicle speed.)
•
010 Gear lock�p Prohibition Control (1. Brake pedal is depressed. 2. Coolant temp. is 60 "C
(140 'F) or less.)
HINT:
(2) Check for shift shock and slip.
Check for shock and slip at the
1
--t 2, 2 --t 3 and 3 --t OlD up-shifts.
(3) Check for abnormal noises and vibration.
Drive in the D position lock-up or OlD gear and check for abnormal noises and vibration.
The
check for the cause of abnormal noises and vibration must be done very thoroughly as it could also be
due to loss
of
balance in the differential torque converter clutch, etc.
(4) Check kick-<iown operation.
W
hi
l
e
ru n
n
i
n
g in the 0 position, 2nd, 3rd and 0/D gears, check to see that the possible kick-down
vehicle speed limits for 2 --t 1 , 3
--t
2 and OlD --t 3 kick-downs conform to those indicated on
the automatic shift schedule {See page SS--41 )
.
(5)
Check abnormal shock and slip at kick-down.
(6) Check the lock-up mechanism.
•
Drive in 0 position, OlD gear, at a steady speed (lock-up ON) of about 60 km/h (37 mph).
•
Lightly depress the accelerator pedal and check that the engine speed does not change
abruptly.
If there is a big jump
in
engine speed, there is no lock-up.