Fuel Injector Circuit Check

Fuel Injector Circuit Check










Troubleshooting

1. Check each injector for operating sound at engine cranking using sound scope.

Do all 4 injector make operating sound?
YES
Furl injector circuit is in good condition.
NO
Go to Step 2.

2. Check fuel injector resistance.

Disconnect connectors from fuel injectors with ignition switch turn OFF.
Check proper connection to fuel injector at each terminals.
If it is OK, check all 4 fuel injectors for resistance, referring to Fuel Injector Inspection Fuel Injector Inspection.

Are all injectors in good condition?
YES
Go to Step 3.
NO
Faulty fuel injector.

3. Check fuel injector insulation resistance.

Check that there is insulating between each fuel injector terminals and engine ground.

Is there insulating?
YES
Go to Step 4.
NO
Faulty fuel injector.

4. Check fuel injector power supply.

Measure voltage between each "BLK/RED" wire terminal and engine ground with ignition switch turned ON.

Is voltage 10 - 14 V?
YES
Go to Step 5.
NO
"BLK/RED" wire open circuit or shorted to ground circuit.
If it is in good condition, go to Component Tests and General Diagnostics ECM Power and Ground Circuit Check.

5. Check wire circuit.

Turn OFF ignition switch.
Disconnect connectors from ECM.
Measure resistance between each "BLU/YEL", "BLU/WHT", "BLU/RED", "BLU/GRN" wire terminal and vehicle body ground.

Is resistance infinity?
YES
Go to Step 6.
NO
"BLU/YEL", "BLU/WHT", "BLU/RED", "BLU/GRN" wire shorted to ground.

6. Check wire circuit.

Measure voltage between each "BLU/YEL", "BLU/WHT", "BLU/RED", "BLU/GRN" wire terminal and vehicle body ground with ignition switch turned ON.

Is voltage 0 V?
YES
Go to Step 7.
NO
"BLU/YEL", "BLU/WHT", "BLU/RED", "BLU/GRN" wire shorted to power supply circuit.

7. Check fuel injector drive signal.

Connect connectors to each fuel injectors and ECM with ignition switch turn OFF.
Turn ON ignition switch.
Measure voltage "C46-20", "C46-8", "C46-1", "C46-2" terminal and vehicle body ground.

Is voltage 10 - 14 V?
YES
Check fuel injector, referring to Fuel Injector Inspection Fuel Injector Inspection.
If result in good condition, substitute a known-good ECM and recheck.
NO
"BLU/YEL", "BLU/WHT", "BLU/RED", "BLU/GRN" open circuit.