Toyota Corolla (E120) 2002–2008 Repair Manual / Diagnostics / Sfi system / Ecm power source circuit / Circuit description
Toyota Corolla (E120): Circuit description
When the ignition switch is turned on, battery positive voltage is applied to the coilwhich closes the contacts of the efi main relay (marked: efi) and supplies power to terminal +b of the ecm.
This signal causes current to flow to the coil, closing the contacts of the efi relay and supplying power to terminal +b of the ecm.
If the ignition switch is turned off, the ecm continues to switch on the efi relay for a maximum of 2 seconds for the initial setting of the isc valve.
Wiring diagram

Other materials:
Ecm/pcm processor
Dtc p0606 ecm/pcm processor
Monitor description
The ecm continuously monitors its internal circuits. This self–check insures
that the ecm is functioning properly.
If a malfunction is detected, the ecm will set the appropriate dtc and
illuminate the mil.
The two cpus, main and sub cpu i ...
Circuit description
Refer to dtc p0115
Dtc no.
Dtc detection condition
Trouble area
P0116
If engine coolant temperature (ect) was between 35 c (95 °F)
and 60 c (140 °F) when starting the engine, and also conditions
(a) and (b) are met:
vehicle has run with acceleration an ...
Engine mechanical
Service data
Torque specification
...


