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Home >> Buick >> 2012 >> Regal Base >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls/Fuel - 2.4L - DTC P0010 To DTC P0411 >> Diagnostic Information and Procedures >> DTC P0191 >> Circuit/System Testing

Circuit/System Testing

  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 5 Ω 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 4.8-5.2 V between the 5 V reference circuit terminal 11 and ground.
    • If less than the specified range, test the 5 V 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 5 V 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 0.02 V.
    • 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 3 A fused jumper wire between the signal circuit terminal 12 and the 5 V reference circuit terminal 11. Verify the scan tool Fuel Rail Pressure Sensor Voltage parameter is greater than 4.96 V.
    • 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 5 Ω 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 4.8-5.2 V between the 5 V reference circuit terminal A and ground.
    • If less than the specified range, test the 5 V reference circuit for a short to ground or an open/high resistance.
    • If greater than the specified range, test the 5 V reference circuit for a short to voltage.
  11. Ignition ON, verify the scan tool Fuel Rail Pressure Sensor voltage parameter is less than 0.02 V.
    • If greater than the specified value, test the signal circuit for a short to voltage.
  12. Connect a 3 A fused jumper wire between the signal circuit terminal B and the 5 V reference circuit terminal A. Verify the scan tool Fuel Rail Pressure Sensor voltage parameter is greater than 4.96 V.
    • 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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