Toyota Corolla (E120): Circuit description
When driving uphill under cruise control, in order to reduce the number of shifting due to on–off overdrive operation and to provide smooth driving, when down shifting in the electronically controlled transmission occurs, a signal to prevent upshift until the end of the uphill slope is sent from the cruise control ecu assy to the electronically controlled transmission.
Terminal ect of the cruise control ecu assy detects the shift change signal (output to electronically controlled transmission no.2 Solenoid) from the ecm.
If the vehicle slows down, also when terminal ect of the cruise control ecu assy receives down shifting signal, it sends a signal from terminal od to ecm to cut overdrive until the end of the uphill slope, and the number of gear shifts are reduced and gear shift points in the electronically controlled transmission are changed.
Wiring diagram

Other materials:
Toyota Safety Sense 3.0
The Toyota Safety Sense 3.0
consists of the driving
assist systems and contributes
to a safe and comfortable
driving experience:
WARNING
■Toyota Safety Sense 3.0
The Toyota Safety Sense 3.0
operates under the assumption
that the driver will drive safely,
and is designed to help reduce
the impact t ...
Exterior
Doors
Locking/unlocking
Opening/closing the side windows
Locking/unlocking by using the mechanical key*1
Warning messages
Trunk
Opening from inside
Opening from outside
Warning messages
Outside rear view mirrors
Adjusting the mirror angle
Folding the mirrors
Defogging the mirrors*2
...
Inspection procedure
1 Inspect shift solenoid valve(s2)
Remove the shift solenoid valve s2.
measure the resistance according to the value(s) in the
table below.
Standard:
Connect the positive (+) battery lead to the solenoid connector
terminal, and the negative (–) battery lead to the
so ...


