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:
Overhaul
1. Remove repair service starter kit
Remove the nut, then disconnect the lead wire from terminal
c.
Remove the 2 screws which are used to secure the repair
service starter kit to the starter drive housing.
remove the repair service starter kit.
remove the return ...
Replacement
1. Remove console box sub–assy rear
2. Remove parking brake lever sub–assy
Disconnect the parking brake switch connector from the
parking brake switch.
remove the lock nut and adjusting nut from the parking
brake cable assy no.1.
Remove the 2 bolts.
Usin ...
Inspection procedure
Hint:
if dtc p0441 (purge flow), p0446 (vsv for ccv or vsv for pressure
switching valve), p0451, p0452
or p0453 is output with dtc p0442 or p0456 , first troubleshoot
dtc p0441, p0446, p0451, p0452 or p0453. If no malfunction is detected,
troubleshoot dtc
p0442 or p0456 next.
...


