Toyota Corolla (E120) 2002–2008 Repair Manual / Diagnostics / Sfi system / Coolant thermostat (coolant
temperature below thermostat
regulating temperature)
Toyota Corolla (E120): Coolant thermostat (coolant temperature below thermostat regulating temperature)
Dtc p0128 coolant thermostat (coolant temperature below thermostat regulating temperature)
Hint
: this is the purpose of the ”thermostat” malfunction detection.
Other materials:
Inspection procedure
1 Check p/t squib(lh) circuit(airbag sensor assy center – front seat
outer belt assy lh)
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 seat belt pretensio ...
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 supplyin ...
Inspection procedure
1 Check security indicator light
Set the system in 30 seconds after filliping the security indicator to
check if the alarm is triggered.
2 Check glass breakage sensor ecu (glass breakage sensor)
Check the continuity and voltage of the glass breakage
sensor ecu, as shown in th ...