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Home >> Buick >> 2017 >> LaCrosse Base >> Repair and Diagnosis (Single Page) >> Engine Performance >> System >> Engine Controls And Fuel - 3.6L (LGX) - DTC P0446 To DTC P3436 And Diagnostic Information And Procedures >> Diagnostic Information and Procedures >> DTC P163A: Control Module Fuel Pressure Regulator 1 >> Circuit/System Testing
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Circuit/System Testing

  1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the G18 High Pressure Fuel Pump. It may take up to 2 min for all vehicle systems to power down.
  2. Verify that a test lamp does not illuminate between the high pressure fuel pump actuator low control circuit terminal 1 and B+.
    • If the test lamp illuminates 
    1. Remove the test lamp.
    2. Disconnect the X3 harness connector at the K20 Engine Control Module.
    3. Test for infinite resistance between the low control circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance, test or replace the K20 Engine Control Module.
    • If the test lamp does not illuminate 
  3. Ignition ON.
  4. Verify a test lamp does not illuminate between the high pressure fuel pump actuator high control circuit terminal 2 and ground.
    • If the test lamp illuminates 
    1. Ignition OFF, remove the test lamp, disconnect the X3 harness connector at the K20 Engine Control Module. Ignition ON.
    2. Test for less than 1 V between the high control circuit and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • If less than 1 V, test or replace the K20 Engine Control Module.
    • If the test lamp does not illuminate 
  5. Verify the test lamp illuminates when the Fuel Pressure Regulator is commanded On with a scan tool.
    • If the test lamp does not illuminate 
    1. Ignition OFF, remove the test lamp, disconnect the X3 harness connector at the K20 Engine Control Module.
    2. Test for less than 2 Ω in the high control circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, test or replace the K20 Engine Control Module.
    • If the test lamp illuminates 
  6. Ignition OFF, connect a test lamp between the high pressure fuel pump actuator low control circuit terminal 1 and B+. Ignition ON.
  7. Verify the test lamp illuminates when the Fuel Pressure Regulator is commanded On with a scan tool.
    • If the test lamp does not illuminate 
    1. Ignition OFF, remove the test lamp, disconnect the X3 harness connector at the K20 Engine Control Module. Ignition ON.
    2. Test for less than 1 V between the low control circuit and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • If less than 1 V
    3. Test for less than 2 Ω in the low control circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, test or replace the K20 Engine Control Module.
    • If the test lamp illuminates 
  8. Test or replace the G18 High Pressure Fuel Pump.
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