Toyota Celica 1993 AT200 series Repair Manual page 295

A X - 1 6
A U T O M A T I C T R A N S A X L E _ T R O U B L E S H O O T I N G
AX
D I A G N O S I S S Y S T E M
' t . o E s c R r P T t o N
( a ) A s e l f - d i a g n o s i s f u n c t i o n i s b u i l t i n t o t h e e l e c t r i c a l
control system. Warning is indicated by the overdrive
OFF indicator,
H I N T : W a r n i n g a n d d i a g n o s t i c c o d e s c a n b e r e a d o n l y
when ths overdrive switch is ON. lf OFF, the overdrive
O F F r n d r c a t o r i s l i t c o n t i n u o u s l v a n d w i l l n o t b l i n k .
lf a malfunction occurs within tha speed sensors
or solenoids, the overdrive OFF light will blink to
warn the driver.
However, there will be no warning of a malfunc-
tion with lock - up solenoid.
The diagnostic code can be read by the number
of blinks of the overdrive OFF indicator whsn
t e r m i n a l s T E 1 a n d E 1 a r e s h o r t - c i r c u i t e d . ( S e e
p a g e A X - 1 7 )
.
The throttlo position sonsor or brake signal are
not indicated, but inspection can be made by
checking the voltage at terminal TT of the check
connoctor.
. The signals to each gear can be checked by
measuring ths voltage at torminal TT of tho
check con nector while driving.
The diagnostic (malfunction) code is retained in
m€mory by the ECU and dua to back - up voltage, is
not canceled out when th6 ongin€ is turned OFF.
Consequently, after repair, it is necessary to turn the
ignition switch OFF and remove th6 EFI fuse (15 A) or
disconnect the ENGINE and ECT ECU conn6ctor to
cancel out the diagnostic (malfunction) code. (See
p a g e A X - l 8 )
H I N T :
.
Low battory voltage will cause faulty operation
of the diagnosis systom. Th€refore, always check
ths battery first.
.
Uso a voltmeter and ohmmeter that have an im-
pedance of at least 1 0 k Q,/V.
CHECK O/D OFF INDICATOR LIGHT
Turn the ignition switch ON.
The OrzD OFF light will coma on when the O/D switch
i s p l a c e d a t O F F .
When the O/D switch is s€t to ON. the O,zD OFF light
should go out.
lf the O/D OFF light flashes when th6 O/D switch is
s6t to ON, the electronic control system is faulty,
(b)
2 .
(a)
(b)
d
t l
'1
ON
o / D
OFF
:o /D"
^ O F F ^
I v t
@?:g
q
OFF
(c)