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:
Although system is powered,cd cannot be played
Wiring diagram
Inspection procedure
1 Check if a proper cd is inserted
Check that a proper cd is inserted.
Make sure that the cd is a normal audio cd, and that there is no
deformation, flaw, stain, burr
and other defects on the cd.
Standard: normal audio cd.
Reference:
...
Precaution
1. Notices when checking
power door lock/unlock function:
the wireless remote control function operates only when the following 3
conditions are met.
No key is inserted into the ignition key cylinder.
All the doors are closed. However, doors can be unlocked even wh ...
Terminals of ecu
Oscilloscope wave (*1)
Hint:
terminal: od – gnd
gauge set: 5 v / div, 50 ms / div
condition: during cruise control driving o/d switch on.
...


