Fuel System: 1G-14
Fuel Injection System Troubleshooting
Z9J0111704003
Before starting the troubleshooting, make sure that:
• There is no self-diagnostic code indication.
• Emergency stop switch plate is set in place.
Step Action Yes No
1 Check fuel injector operating sound.
• Check each injector for operating sound at engine
cranking. ()(Page 1G-21))
Do all 4 injector make operating sound?
Fuel injector circuit is in
good condition.
Go to step 2.
2 Check fuel injector resistance.
• Turn ignition switch off, disconnect connectors from fuel
injectors.
• Check for proper connection to fuel injector at each
terminal.
• If good condition, check all fuel injector for resistance.
()(Page 1G-21))
Are all injectors in good condition?
Go to step 3. Faulty fuel injector.
3 Check fuel injector power supply.
• Measure voltage between each “Gray” wire terminal of
fuel injector connector and engine body ground with
ignition switch turned “ON”.
Is voltage 10 – 14 V?
Go to step 4. • “Gray” wire open or
shorted.
• If it is in good
condition, check ECM
power source and
ground circuit.
4 Check Wire circuit.
• Turn “OFF” ignition switch.
• Disconnect connector from ECM.
• Measure resistance between each “O/B”, “B/Br”, “R/W”,
“Lg” wire terminal of the fuel injector connector and body
ground.
Is resistance infinity?
Go to step 5. “O/B”, “B/Br”, “R/W”,
and/or “Lg” wire(s) are
shorted to ground.
5 Check Wire circuit.
• Connect connector to ECM.
• Measure voltage between each “O/B”, “B/Br”, “R/W”, “Lg”
wire terminal of fuel injector connector and body ground
with ignition switch turned “ON”.
Is voltage 0 V?
Go to step 6. “O/B”, “B/Br”, “R/W”,
and/or “Lg” wire(s) are
shorted to power supply
circuit.
6 Check fuel injector operating signal.
• Connect connectors to each fuel injector and ECM with
ignition switch turned “OFF”.
• Measure fuel injector operating signal between each “45”,
“71”, “47”, “59” terminal of ECM and body ground.
()(Page 1G-22))
Is voltage 6 – 10 V or over?
If check result is
satisfactory, substitute a
known-good ECM and
recheck.
“O/B”, “B/Br”, “R/W”,
and/or “Lg” wire(s) are
open circuit.
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