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Home >> Subaru >> 1995 >> Legacy Sedan 2WD F4-2.2L SOHC >> Repair and Diagnosis >> Powertrain Management >> Computers and Control Systems >> Main Relay (Computer/Fuel System) >> Testing and Inspection >> Fuel Pump Relay
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Fuel Pump Relay

CHECKING FUEL PUMP POWER SUPPLY




Fuel Pump Circuit Diagram:




Fuel Pump Circuit Connectors:





FUEL PUMP CIRCUIT
1. Check operating sound of Fuel Pump.
- Make sure that Fuel Pump is in operation for two seconds when turning Ignition Switch to "ON".
[CHECK]: Does Fuel Pump produce operating sound?
[YES]: Check Fuel Injector circuit.
[NO]: Go to step 2.





2. Check ground circuit of Fuel Pump.
a. Turn Ignition Switch to "OFF".
b. Disconnect connector from Fuel Pump.
c. Measure resistance of harness connector between Fuel Pump and body.
[CHECK]: Connector & terminal:
(R58) No. 4 - Body/10 Ohms or less.
[YES]: Go to step 3.
[NO]: Repair open circuit of Fuel Pump ground circuit.





3. Check power supply to Fuel Pump.
a. Turn Ignition Switch to "ON".
b. Measure voltage of power supply circuit between Fuel Pump connector and body.
[CHECK]: Connector & terminal:
(R58) No. 1 - Body/10 Volts or more.
[YES]: Replace Fuel Pump.
[NO]: Go to step 4.





4. Check harness connector between Fuel Pump and Fuel Pump Relay.
a. Turn Ignition Switch to "OFF".
b. Measure resistance of harness connector between Fuel Pump and Fuel Pump relay.
[CHECK]: Connector & terminal:
(R58) No. 1 - (B46) No. 4/10 Ohms or less.
[YES]: Go to next [CHECK].
[NO]: Repair open circuit of harness between Fuel Pump and Fuel Pump relay connector,

[CHECK]: Connector & terminal:
(R58) No. 1 - Body/1 M-Ohms or more.
[YES]: Go to step 5.
[NO]: Repair short circuit of harness between Fuel Pump and Fuel Pump relay connector.





5. Check Fuel Pump Relay.
a. Disconnect connectors from Fuel Pump relay and Main Relay .
b. Remove Fuel Pump relay and Main Relay with bracket.
c. Connect Battery to Fuel Pump relay connector terminals No. 1 and No. 3.
d. Measure resistance between connector terminals of Fuel Pump relay.
[CHECK]: Terminals:
No. 2 - No. 4/10 Ohms or less.
[YES]: Go to step 6.
[NO]: Replace Fuel Pump relay.





6. Check harness connector between Engine Control Module (ECM) and Fuel Pump Relay.
a. Disconnect connectors from ECM.
b. Measure resistance of harness connector between ECM and Fuel Pump relay.
[CHECK]: Connector & terminal:
(B84) No. 84 - (B46) No. 3/10 Ohms or less.
[NO]: Repair harness between ECM and Fuel Pump relay connector.
[YES]: Confirm good connection in ECM connector.

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