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Home >> Buick >> 2015 >> Regal GS, AWD >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 15 (Engine Controls And Fuel - 2.4L - DTC P0114 To DTC P0604) >> Diagnostic Information and Procedures >> DTC P0191: Fuel Rail Pressure Sensor >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different variant/trim than selected.
  1. Ignition OFF, disconnect the fuel injector multi-way harness connector X160.
    2. NOTE:

    Testing for steps 2 through 5 is performed on the ECM side of the multi-way harness connector.

  2. Ignition OFF and all vehicle systems OFF. It may take up to 2 minutes for all vehicle systems to power down. Test for less than 5Ω between the low reference circuit terminal 5 and ground.
    • If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the K20 ECM.
  3. Ignition ON, test for 4.8-5.2V between the 5V reference circuit terminal 11 and ground.
    • If less than the specified range, test the 5V reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K20 ECM.
    • If greater than the specified range, test the 5V reference circuit for a short to voltage. If the circuit tests normal, replace the K20 ECM.
  4. Ignition ON, verify the scan tool Fuel Rail Pressure Sensor voltage parameter is less than 0.02V.
    • If greater than the specified value, test the signal circuit for a short to voltage. If the circuit tests normal, replace the K20 ECM.
  5. Connect a 3A fused jumper wire between the signal circuit terminal 12 and the 5V reference circuit terminal 11. Verify the scan tool Fuel Rail Pressure Sensor Voltage parameter is greater than 4.96V.
    • If less than the specified value, test the signal circuit for an open/high resistance or a short to ground. If the circuit tests normal, replace the K20 ECM.
  6. Ignition OFF, remove the intake manifold.
  7. Connect the fuel injector multi-way harness connector X160.
    8. NOTE:

    Testing for steps 9 through 12 is performed at the fuel rail fuel pressure sensor connector.

  8. Disconnect the B47B fuel rail fuel pressure sensor connector.
  9. Ignition OFF, test for less than 5Ω between the low reference circuit terminal C and ground.
    • If greater than the specified range, test the low reference circuit for an open/high resistance.
  10. Ignition ON, test for 4.8-5.2V between the 5V reference circuit terminal A and ground.
    • If less than the specified range, test the 5V reference circuit for a short to ground or an open/high resistance.
    • If greater than the specified range, test the 5V reference circuit for a short to voltage.
  11. Ignition ON, verify the scan tool Fuel Rail Pressure Sensor voltage parameter is less than 0.02V.
    • If greater than the specified value, test the signal circuit for a short to voltage.
  12. Connect a 3A fused jumper wire between the signal circuit terminal B and the 5V reference circuit terminal A. Verify the scan tool Fuel Rail Pressure Sensor voltage parameter is greater than 4.96V.
    • If less than the specified value, test the signal circuit for an open/high resistance or a short to ground.
  13. If all circuits test normal, replace the B47B fuel rail fuel pressure sensor.
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