Toyota 4A-FE Repair Manual page 119

Fl-50
EFI SYSTEM - Troubleshooting with Volt/Ohmmeter
From EFI Main Relay
Voltmeter
Cl]
TE1
Check Connector
~ij-_ ~, Voltmeter
v :
'"!--------...
Check Connector
VF1
Oxygen Sensor
VF
T
ECU
Oxygen Sensor Heater
(w/
EGR syst_e_m_) _ _,
HT
Fl3840
CD CD
There is no voltage between ECU terminals VF and El.
ECU
fl4056
®
SST
EM7602
EM7601
Check that there is voltage between ECU terminal VF and body
ground.
NO OK
Check wiring between ECU terminal El and body ground.
OK
BAD
Try
another ECU. Repair or replace.
Is air leaking into air intake system?
BAD
Repair air leak.
OK
Check spark plugs.
BAD
Repair or replace.
OK
Check distributor and ignition system.
BAD
Repair or replace.
OK
Check fuel pressure.
BAD
Repair or replace.
OK
Check injector.
BAD
Repair or replace.
OK
Check · c old start injector.·
BAD
Repair or replace.
OK
Check vacuum sensor.
BAD
Repair or replace.
OK
2
Check operation of oxygen sensor.
OK
System normal.
BAD
Check wiring between oxygen sensor
BAD
and ECU connector.
Repair wiring.
OK
Replace oxygen sensor. •Rich malfunction only