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Home >> Suzuki >> 2006 >> Swift + >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - 1.6L (L91) - Troubleshooting & Diagnosis >> Fuel Pump Electrical Circuit Diagnosis >> Circuit/System Testing
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Circuit/System Testing

  1. Ignition OFF, the fuel pump should not be operating.
    • If the fuel pump operates continuously, test for a short to voltage in the fuel pump supply voltage circuit. If the circuit/connections test normal, replace the fuel pump relay.
  2. Ignition OFF, remove the fuel pump relay from the electrical center.
    3. IMPORTANT: The test lamp is used to load the circuit and may not illuminate.
  3. Connect a test lamp between the ground circuit of the fuel pump relay and the positive terminal of the battery.
  4. Ignition ON, test for less than 0.1 volt between the ground circuit of the fuel pump relay and the negative terminal of the battery.
    • If greater than 0.1 volt, repair the ground circuit of the fuel pump relay for an open/high resistance.
  5. Connect a test lamp between the ignition 1 voltage circuit of the fuel pump relay and the negative terminal of the battery.
  6. Ignition ON, test for less than 0.1 volt between the ignition 1 voltage circuit of the fuel pump relay and the positive terminal of the battery.
    • If greater than 0.1 volt, repair the ignition 1 voltage circuit of the fuel pump relay for a short to ground or an open/high resistance.
  7. Connect a 15-amp fused jumper wire between the ignition 1 voltage circuit of the fuel pump relay and the supply voltage circuit of the fuel pump. The fuel pump should operate.
    • If the fuel pump does not operate, test for the following conditions:
    • An open/high resistance in the motor circuit of the fuel pump
    • An open/high resistance in the ground circuit of the fuel pump
    • If the above circuit/connections test normal, replace the fuel pump.
  8. With the ignition OFF, connect a test lamp between the control circuit and the ignition 1 voltage circuit of the fuel pump relay.
  9. With the ignition ON, use a scan tool to command the fuel pump relay ON and OFF. The test lamp should turn ON and OFF with each command.
    • If the test lamp remains ON all the time, test for a short to ground on the control circuit. If the circuit/connections test normal, replace the ECM.
    • If the test lamp remains OFF all the time, test for a short to voltage or an open/high resistance on the control circuit. If circuit/connections test normal, replace the ECM.
  10. If all circuit/connections test normal, test or replace the fuel pump relay.
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