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Home >> GMC >> 2018 >> Acadia Denali, FWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 354 (Engine Controls And Fuel - 3.6L (LGX) - DTC P0010 To DTC P0459) >> Diagnostic Information and Procedures >> DTC P0090-P0092, P00C8, P00C9, or P00CA: Fuel Pressure Regulator >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2017 GMC Acadia. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the G18 High Pressure Fuel Pump, ignition ON. 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 control circuit terminal 2 and ground.
    • If the test lamp illuminates 
    1. Ignition OFF, remove the test lamp, disconnect the 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, replace the K20 Engine Control Module.
      • If the test lamp does not illuminate 
  3. Verify that a test lamp does not illuminate between the low control circuit terminal 1 and ground.
    • If the test lamp illuminates 
    1. Ignition OFF, remove the test lamp, disconnect the 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, replace the K20 Engine Control Module.
      • If the test lamp does not illuminate 
  4. Verify that a test lamp does not illuminate between the high control circuit terminal 2 and B+.
    • If the test lamp illuminates 
    1. Ignition OFF, remove the test lamp, disconnect the harness connector at the K20 Engine Control Module.
    2. Test for infinite resistance between the high control circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance, replace the K20 Engine Control Module.
    • If the test lamp does not illuminate 
  5. Verify that a test lamp does not illuminate between the low control circuit terminal 1 and B+.
    • If the test lamp illuminates 
    1. Ignition OFF, remove the test lamp, disconnect the harness connector at the K20 Engine Control Module.
    2. 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, replace the K20 Engine Control Module.
    • If the test lamp does not illuminate 
  6. Remove the test lamp, connect a 3 A fused jumper wire between the high control circuit terminal 1 and ground.
    7. NOTE:

    For steps 7-9 it may be necessary to Start/Crank the engine to update the scan tool parameter.

  7. Verify the Fuel Pressure Regulator High Control Circuit Low Voltage Test Status transitions from OK to Malfunction.
    • If Malfunction is not displayed 
    1. Ignition OFF, remove the fused jumper, disconnect the 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, replace the K20 Engine Control Module.
    • If Malfunction is displayed 
  8. Connect a 3 A fused jumper wire between the low control circuit terminal 2 and B+.
  9. Verify the Fuel Pressure Regulator Control Circuit High Voltage Test Status transitions from OK to Malfunction.
    • If Malfunction is not displayed 
    1. Ignition OFF, remove the fused jumper, disconnect the harness connector at the K20 Engine Control Module.
    2. 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, replace the K20 Engine Control Module.
    • If Malfunction is displayed 
  10. Test or replace the G18 High Pressure Fuel Pump.
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