Toyota Corolla (E120) 2002–2008 Repair Manual / Diagnostics / Sfi system / System voltage / Monitor description
Toyota Corolla (E120): Monitor description
The battery supplies electricity to the ecm even when the ignition switch is off. This electricity allows the ecm store data such as dtc history, freeze frame data, fuel trim values, and other data. If the battery voltage falls below a minimum level, the ecm will conclude that there is a fault in the power supply circuit. At the next engine start, the ecm will turn on the mil and a dtc will be set.

Monitor strategy

*1: The dtc is set immediately. The mil will be illuminated after the next engine start.
Typical enabling conditions

Typical malfunction thresholds

Wiring diagram

Other materials:
If the vehicle battery is discharged
The following procedures
may be used to start the
engine if the vehicle's battery
is discharged.
You can also call your Toyota
dealer or a qualified
repair shop.
Restarting the engine
If you have a set of jumper (or
booster) cables and a second
vehicle with a 12-volt battery,
you can jump start you ...
On–vehicle inspection
1. Inspect refrigerant pressure with manifold gauge set
this is a method in witch the trouble is located by using
a manifold gauge set. Read the manifold gauge pressure
when the these conditions are established.
Test conditions:
temperature at the air inlet with the switch set
...
Inspection procedure
1 Check d squib circuit(airbag sensor assy center – horn button
assy)
Disconnect the negative (–) terminal cable from the battery,
and wait at least for 90 seconds.
disconnect the connectors between the airbag sensor
assy center and the horn button assy.
release the airbag ...


