Toyota Celica Supra 1986 Service And Repair Manual page 291

AT-16 AUTOMATIC TRANSMISSION - Electric Cont rol
~
Trouble No. 4 No u p-shift to o verd rive (After w orm-up)
ll
Road test while shifting manually with ECT ECU
No
coMector
pulled
out. Is there overdrive up·shift in 0
Fautty transmission
range w hen stlif'ilng from L to 2 to 0?
Yes
'
~
.u.
'"' ECT ECU connect or, and
lo -
7V
• Faulty
while driving does DG terminal voltage
•
•
1
rise from
OV
to
7V
in sequence?
"
0 - SV
ov
•
0 -
3V
There is 1 2V between ECT ECU terminals)
2 and GNO when 0
I
Yes
I
No
There is 12V between ECT ECU
terminals
l ~nd
GNO
0
No !Yes
•
neutral start
circuit
•
neutral start switch
I
Try another ECT ECU
Is voltage between terminals
00:~
and GNO as
•
Faulty 00 switch
follows? I
No
harness
00 switch turn ON: 12V (Aisin) or 5V (Oenso•
• Faulty 00 switch
00 , turn OFF: OV
• DO off light ooen
I
I
Yes '
' '
'
•check 00 cutout signan
'
..
:
Is voltage between terminals 00 and GNO as follows?
!
Approx.
SV IDenso) or 12V (Aisin)
Yes
(coolant temp. above 70°C or 158°F) Try onother ECT ECU
I
No
(Check 00 cutout signal)
Is
IECU
Yes
~.
olt•
I
oo,
and GND normal with the cruise
cruise control
connector .. n ..
A
out?
No
Faulty engine ECU
'
($hort circuit in ECT w ire harness
'
or EFI water sensor bad)
.