Toyota Corolla (E120) 2002–2008 Repair Manual / Diagnostics / Supplemental restraint system / Airbag sensor assy malfunction / Circuit description
Toyota Corolla (E120): Circuit description
The airbag sensor assy center consists of a airbag sensor assy center, safing sensor, drive circuit, diagnosis circuit and ignition control, etc.
It receives signals from the airbag sensor, judges whether or not the srs must be activated, and detects diagnosis system malfunction.
Dtc b1100/31 is recorded when occurrence of a malfunction in the airbag sensor assy center is detected.

Inspection procedure
Hint
: when a malfunction code other than code b1100/31 is displayed at the same time, first repair the malfunction indicated by the malfunction code other than code b1100/31.
Other materials:
Automatic transaxle fluid (atm)
On–vehicle inspection
1. Check the fluid level
Hint:
drive the vehicle so that the engine and transaxle are at normal
operating temperature.
Fluid temperature: 70 – 80 °c (158 – 176 °f)
park the vehicle on a level surface and set the parking
brake.
with the engin ...
Circuit description
The ignition switch provides circuit power and the ecm provides the circuit
ground that illuminates the mil.
Mil operation is checked visually:
it should be illuminated when the ignition is first turned on. If the mil is off
all of the time or on all of the time,
use the procedure below to ...
Inspection procedure
1 Check ignition or starter switch assy
Check the ignition switch, as shown in the illustration and
table.
Standard:
2 Check fuse (ecu–b)
Remove the fuse from the instrument panel j/b.
check the continuity of the fuse.
Standard: continuity
3 Check relay (m ...


