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:
Air bag sensor front lh
Components
Replacement
Hint: components:
1. Precaution
2. Disconnect battery negative terminal
3. Remove air bag sensor front lh
Disconnect the connector from the airbag sensor front
lh.
remove the 2 bolts and airbag sensor front lh.
4. Inspect air bag sensor front lh
...
Inspection procedure
1 Check wire harness(dlc3 – airbag sensor assy center)
Turn the ignition switch to the lock position.
disconnect the aribag sensor assy center connector.
measure the resistance according to the value(s) in the
table below.
Standard:
2 Check wire harness(cg of dl ...
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.
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