Toyota Corolla (E120) 2002–2008 Repair Manual / Diagnostics / Toyota vehicle intrusion protection system / Horn relay circuit / Circuit description
Toyota Corolla (E120): Circuit description
When the tvip system is transferred from the armed state to the alarm sounding state, the tvip ecu switches on the horn relay so that it can sound the horns. The horn sounds in 0.4 Seconds interval.
Wiring diagram

Other materials:
Check mode procedure
Hint:
hand–held tester only:
compared to the normal mode, the check mode has more sensing
ability to detect malfunctions. Furthermore, the same diagnostic
items which are detected in the normal mode can also be
detected in the check mode.
1. Check mode procedure(using the hand–held tester) ...
Overhaul
Hint: components:
1. Drain manual transaxle oil (m/t transaxle)
torque: 39.2 Nvm (400 Kgf·cm, 29 ft·lbf)
2. Drain automatic transaxle fluid (a/t transaxle)
torque: 17.5 Nvm (178 Kgf·cm, 13 ft·lbf)
3. Remove front wheel
4. Remove engine under cover lh
5. Remove front axle hub lh nut
...
Source voltage drop
The srs is equipped with a voltage–increase circuit (dc–dc converter) in the
airbag sensor assy center
in case the source voltage drops.
When the battery voltage drops, the voltage–increase circuit (dc–dc converter)
functions to increase the
voltage of the srs to normal voltage.
...


