1A
Fuel Pump and Its Circuit Check
Wiring Diagram
1. Relay box 4. Fuel pump relay 7. Ignition switch
2. Main relay 5. Fuel pump 8. “FI” fuse
3. ECM 6. “IG” fuse 9. “IGN1” fuse
Troubleshooting
Step Action YES NO
1
Fuel pump control system check for operation
Is fuel pump heard to operate for 2 sec. after ignition switch ON?
Fuel pump circuit is in good condition.
Go to Step 2.
2
Fuel pump relay power supply check
1) Disconnect fuel pump relay from relay box with ignition switch turned OFF.
2) Check for proper connection to fuel pump relay at each terminals.
3) If OK, turn ON ignition switch, measure voltage between “BLK/WHT” wire terminal of fuel pump relay connector and engine ground.
Is voltage 10 – 14 V?
Go to Step 3.
“BLK/WHT” wire open or shorted to ground circuit.
3
Fuel pump relay power supply check
1) 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 open circuit.
4
Fuel pump relay check
1) Check fuel pump relay referring to Main Relay, Fuel Pump Relay, A/C Compressor Relay and A/C Condenser Fan Control Relay Inspection:M13A .
Is relay in good condition?
Go to Step 5.
Faulty relay.
5
Fuel pump relay drive signal check
1) Connect fuel pump relay to relay box.
2) Connect voltmeter between “E117-14” terminal of ECM connector and vehicle body ground.
3) Measure voltage at after 2 second ignition switch turned ON.
Is voltage 10 – 14 V?
Go to Step 6.
“WHT/GRN” wire open circuit or shorted to ground circuit.
6
Fuel pump relay drive signal check
1) Measure voltage at within 2 second after ignition switch turned ON.
Is voltage 0 – 1 V?
Go to Step 7.
Substitute a known-good ECM and recheck.
7
Wire circuit check
1) Turn OFF ignition switch.
2) Detach fuel tank referring to Fuel Tank Removal and Installation:M13A .
3) Disconnect connector from fuel pump.
4) Measure resistance between “PNK” wire terminal of fuel pump connector and vehicle body ground.
Is resistance infinity?
Go to Step 8.
“PNK” wire shorted to ground.
8
Fuel pump circuit check
1) Turn OFF ignition switch.
2) Connect service wire between “E117-14” terminal of ECM connector and vehicle body ground.
3) 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 open circuit.
9
Fuel pump circuit check
1) Turn OFF ignition switch.
2) Measure resistance between “BLK” wire terminal at fuel pump connector and vehicle body ground.
Is it resistance less than 5 Ω?
Faulty fuel pump.
“BLK” wire open circuit.