Toyota Corolla (E120): Circuit description
The srs warning light is located on the combination meter.
When the srs is normal, the srs warning light lights up for approx. 6 Seconds after the ignition switch is turned from the lock position to on position, and then turns off automatically.
If there is a malfunction in the srs, the srs warning light lights up to inform the driver of the abnormality.
When terminals tc and cg of the dlc3 are connected, the dtc is displayed by blinking the srs warning light.
Wiring diagram

Other materials:
Data list/active test
1. Data list
Hint:
using the data list displayed by the hand–held tester or the obd ii scan tool,
you can read the value of
the switches, sensors, actuators and so on without parts removal. Reading the
data list as a first step
of troubleshooting is one method to shorten diagnostic time.
...
Inspection procedure
1 Inspect dlc3 terminal voltage
Turn the ignition switch to on.
measure voltage between terminals 13 (tc) and 4 (cg) of
dlc3.
Ok:
voltage: 10 – 16 v
2 Check harness and connector(between cruise control ecu assy
and dlc3)
Check for open and short circuit in harness ...
General information
There are many ecu controlled systems used in the corolla. In general, ecu
controlled system are considered
to be very intricate and require a high level of technical knowledge and expert
skill to troubleshoot.
The fact is, however, that if you proceed by inspecting the circuits one by one, ...


