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:
Inspection
1. Cooling fan relay
Inspect the cooling fan relay continuity.
Using an ohmmeter, check that there is continuity
between terminals 1 and 2.
If there is no continuity, replace the relay.
Check that there is no continuity between terminals
3 and 5.
If there is conti ...
Inspection procedure
Hint:
read freeze frame data using the hand–held tester or the obd ii scan tool.
Freeze frame data records the
engine conditions when a malfunction is detected. When troubleshooting, it is
useful for determining whether
the vehicle was running or stopped, the engine was warmed up or not, th ...
Inspection procedure
1 Inspect ecm(+b voltage)
Turn the ignition switch on.
measure the voltage between the terminals of the e4 and
e6 ecm connectors.
Standard:
2 Check harness and connector(ecm – body ground)
Disconnect the e4 ecm connector.
check the resistance between the wire ...