Fuel Pump And Its Circuit Check: Troubleshooting

NOTE:

• Before performed troubleshooting, be sure to read the Precautions of ECM Circuit Inspection.
• When measuring circuit voltage, resistance and/or pulse signal at ECM connector, connect the special tool to ECM and/or the ECM connectors referring to INSPECTION OF ECM AND ITS CIRCUITS .

DTC TROUBLESHOOTING CHART

Step	Action	YES	NO
1	Fuel pump control system check for operation  Is fuel pump heard to operate 2 sec. after ignition switch is turned ON?	Fuel pump circuit is in good condition.	Go to Step 2.
2	Fuel pump relay power supply check  Disconnect fuel pump relay from fuse box No. 2 with ignition switch turned OFF. Check for proper connection to fuel pump relay at each terminal. If OK, turn ON ignition switch, measure voltage between "WHT/GRN" wire terminal of fuel pump relay connector and engine ground. Is voltage 10 - 14 V?	Go to Step 3.	"WHT/GRN" wire is open or shorted to ground circuit.
3	Fuel pump relay power supply check  Turn ON ignition switch, measure voltage between "BLU/BLK" wire terminal of fuel pump relay connector and engine ground. Is voltage 10 - 14 V?	Go to Step 4.	"BLU/BLK" wire is open circuit.
4	Fuel pump relay check  Check fuel pump relay referring to ENGINE AND EMISSION CONTROL SYSTEM RELAY INSPECTION . Is relay in good condition?	Go to Step 5.	Faulty relay.
5	Fuel pump relay drive signal check  Connect fuel pump relay to fuse box No. 2. Connect voltmeter between "E23-24" terminal of ECM connector and vehicle body ground. Measure voltage 2 second after ignition switch is turned ON. Is voltage 10 - 14 V?	Go to Step 6.	"WHT/GRN" wire is open circuit or shorted to ground circuit.
6	Fuel pump relay drive signal check  Measure voltage within 2 second after ignition switch is turned ON. Is voltage 0 - 1 V?	Go to Step 7.	Substitute a known-good ECM and recheck.
7	Wire circuit check  Turn OFF ignition switch. Detach fuel tank referring to FUEL TANK REMOVAL AND INSTALLATION . Disconnect connector from fuel pump. Measure resistance between "PNK" wire terminal of fuel pump connector and vehicle body ground. Is resistance infinity?	Go to Step 8.	"PNK" wire is shorted to ground.
8	Fuel pump circuit check  Connect service wire between "E23-24" terminal of ECM connector and vehicle body ground. Turn ON ignition switch, measure voltage between "PNK" terminal at fuel pump connector and vehicle body ground. Is voltage 10 - 14 V?	Go to Step 9.	"PNK" wire is open circuit.
9	Fuel pump circuit check  Turn OFF ignition switch. Measure resistance between "BLK" wire terminal at fuel pump connector and vehicle body ground. Is resistance less than 5 Ω?	Faulty fuel pump.	"BLK" wire is open circuit.