For Primary Fuel Injectors

• Remove the air cleaner housing (see Air Cleaner Housing Removal).
• Disconnect the injector connector and connect the harness adapter [A] between these connectors as shown in the figure.

Main Harness [B] Primary Fuel Injector #1 [C]

Special Tool - Measuring Adapter: 57001-1700

• Connect a digital meter [D] to the harness adapter lead.

Primary Fuel Injector Power Source Voltage Connections to Adapter:

For Primary Fuel Injector #1, #2, #3, #4

Digital Meter (+) → R (injector W/R) lead

Digital Meter (–) → Battery (–) terminal

• Measure the power source voltage with the engine stopped.
• Turn the engine stop switch to run position.
• Turn the ignition switch to ON.

Power Source Voltage Standard: Battery Voltage for 3 seconds, and then 0 V

• Turn the ignition switch to OFF

If the reading stays on battery voltage and never shows 0 V, check the fuel pump relay (see Relay Circuit Inspection in the Electrical System chapter).

If the fuel pump relay is normal, check the ECU for its ground and power supply (see ECU Power Supply Inspection).

If the ground and power supply are good, replace the ECU (see ECU Removal/Installation).

If there is still no battery voltage, check the fuel pump relay (see Relay Circuit Inspection in the Electrical System chapter).

If the ground and power supply are good, replace the ECU (see ECU Removal/Installation).

If there is still no battery voltage, check the fuel pump relay (see Relay Circuit Inspection in the Electrical System chapter).

If the fuel pump relay is normal, check the power source wiring (see wiring diagram in this section).

Special Tool - Hand Tester: 57001-1394

If the wiring is good, check the ECU for its ground and power supply (see ECU Power Supply Inspection).

If the ground and power supply are good, replace the ECU (see ECU Removal/Installation).

If the reading is in specification, check the output voltage (see Fuel Injector Output Voltage Inspection).