Toyota Corolla (E120) 2002–2008 Repair Manual / Diagnostics / Sfi system / Stop light switch circuit / Circuit description
Toyota Corolla (E120): Circuit description
This signal is used to detect that the brakes have been applied. The stp signal voltage is the same as the one supplied to the stop lights.
The stp signal is used mainly to control the fuel cut–off engine speed (the fuel cut–off engine speed is reduced slightly when the vehicle is braking.).
Wiring diagram

Other materials:
How to proceed with troubleshooting
The hand–held tester can be used at step 3, 4, 6, 9.
1 Vehicle brought to workshop
2 Customer problem analysis
3 Connect the obd ii scan tool or hand–held tester to dlc3
4 Check and clear dtc and freeze frame data
5 Visual inspection
6 Setting the check mode diagnosis
7 Proble ...
Circuit description
Refer to dtc p0120
Dtc no.
Dtc detection condition
Trouble area
P0121
The following condition is met 4 times. After the vehicle speed
has exceeded 19 mph (30 km/h) once, the throttle position
sensor output value is out of normal range when the throttle
...
Circuit description
Shifting from 1st to o/d is performed in combination with on and off of the
shift solenoid valve s1 and s2
controlled by ecm. If an open or short circuit occurs in either of the solenoid
valves, the ecm controls the
remaining normal solenoid valve to allow the vehicle to be operated smoothly
...


