Toyota Corolla (E120) 2002–2008 Repair Manual / Diagnostics / Sfi system / Fuel pump control circuit / Circuit description
Toyota Corolla (E120): Circuit description
In the diagram below, when the engine is cranked, current flows from terminal st2 of the ignition switch to the starter relay coil and also current flows to terminal sta of the ecm (sta signal).
When the sta signal and ne signal are input to the ecm, tr is turned on, current flows to the coil of the circuit opening relay, the relay switches on, power is supplied to the fuel pump and the fuel pump operates.
While the ne signal is generated (engine running), the ecm keeps tr on (circuit opening relay on) and the fuel pump also keeps operating.
Wiring diagram
Other materials:
Instrument panel
Engine switch
Starting the engine/changing the positions*1
Starting the engine/changing the modes*2
Emergency stop of the engine
When the engine will not start
Warning messages
Shift lever
Changing the shift position
Precautions for towing
When the shift lever does not move
Meters
Read ...
Check dlc3
The vehicle’s ecm uses the iso 9141–2 for communication
protocol. The terminal arrangement of the dlc3 complies
with sae j1962 and matches the iso 9141–2 format.
Hint:
if the display shows unable to connect to vehicle
when you have connected the cable of the obd ii scan tool or
the h ...
Circuit description
The ecm compares the two waveforms of the heated oxygen sensors located
before and after the catalyst
to determine whether or not the catalyst performance has deteriorated.
Air–fuel ratio feedback compensation keeps the waveform of the heated oxygen
sensor in front of the catalyst
alterna ...