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Fuel Pump Circuit Tests

  1. Check Fuel Pump Operation In D-CHECK Mode  - Connect test mode terminal. Turn ignition on. Ensure there is proper fuel pump operation. If fuel pump operates properly, go to next step. If fuel pump does not operate properly, see SVX under FUEL INJECTOR CIRCUIT TESTS  .
  2. Check Fuel Pump Relay  - Disconnect fuel pump relay connector and remove fuel pump relay from bracket. Ensure there is 70 ohms of resistance between fuel pump relay terminals No. 1 and 3. Replace fuel pump relay if resistance is not as specified. If resistance is okay, connect battery voltage positive lead to terminal No. 3 and negative lead to terminal No. 1. If fuel pump relay does not click, replace it. If fuel pump relay clicks, verify zero ohms resistance between terminals No. 2 and 4. If there is zero ohms resistance, go to next step. If there is resistance measured, replace fuel pump relay.
  3. Check Power Supply To Fuel Pump Relay  - Turn ignition off and connect fuel pump relay. Turn ignition on and measure voltage between fuel pump relay connector terminal No. 3 and ground. If at least 10 volts are present, go to next step. If at least 10 volts are not present, repair harness or connectors as necessary.
  4. Check Input Signal For ECU  - Turn ignition on. Ensure there is at least 10 volts between ECU 26-pin connector terminal No. 23 (Green/Black wire) and ground. Crank engine while measuring voltage. Ensure there is zero volts between ECU 26-pin connector terminal No. 23 (Green/Black wire) and ground. If voltage is not as specified, go to next step. If voltage is as specified, go to step 6).
  5. Check Harness Connector Between ECU & Fuel Pump  - Turn ignition off. Disconnect ECU 26-pin harness connector and fuel pump relay 4-pin harness connector. Ensure there is zero ohms resistance between ECU connector terminal No. 23 and fuel pump relay connector No. 3 (Green/Black wire). Ensure there is at least one ohm resistance between fuel pump relay terminal No. 3 (Green/Black wire) and ground. If resistance is not as specified, repair harness or connectors as necessary. If resistance is as specified, inspect ECU connector terminal and repair as necessary. If ECU connector is okay, replace ECU.
  6. Check Voltage For Fuel Pump  - Fold down rear seat back and turn up floor mat. Remove fuel pump access hole cover. Disconnect fuel pump connector. Ensure there is at least 10 volts between fuel pump connector terminal No. 1 (Blue wire) and ground. If at least 10 volts are present, go to next step. If at least 10 volts are not present, repair harness or connectors between fuel pump relay and fuel pump as necessary.
  7. Check Fuel Pump Operation  - Connect battery voltage to fuel pump connector terminal No. 1 and ground to terminal No. 4. If fuel pump operates, repair or replace harness connector fuel pump ground circuit. If fuel pump does not operate, replace fuel pump.
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