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Home >> Chevrolet >> 2018 >> Suburban 3500 HD LT >> Repair and Diagnosis >> External Pages >> Different car >> Section 9 (Engine Controls And Fuel - 5.3L (L83) Or 6.2L (L86) - DTC P0443 To DTC P3452 And Diagnostic Information And Procedures) >> Diagnostic Information And Procedures >> DTC P163A: Control Module Fuel Pressure Regulator 1 Control System Circuitry Performance >> Circuit/System Testing

Circuit/System Testing

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  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. Ignition ON.
  3. Verify that a test lamp does not illuminate between the high control circuit terminal 1 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, replace the K20 Engine Control Module.
    • Go to next step: If the test lamp does not illuminate 
  4. Verify that a test lamp does not illuminate between the low 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 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.
    • Go to next step: If the test lamp does not illuminate 
  5. Verify that a test lamp does not illuminate between the high control circuit terminal 1 and B+.
    • If the test lamp illuminates 
    1. Ignition OFF, remove the test lamp, disconnect the X3 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.
    • Go to next step: If the test lamp does not illuminate 
  6. Verify that a test lamp does not illuminate between the low control circuit terminal 2 and B+.
    • If the test lamp illuminates 
    1. Ignition OFF, remove the test lamp, disconnect the X3 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.
    • Go to next step: If the test lamp does not illuminate 
  7. Remove the test lamp, connect a 3 A fused jumper wire between the high control circuit terminal 1 and ground.
  8. Verify the Fuel Pressure Regulator 1 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 X3 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.
    • Go to next step: If Malfunction is displayed 
  9. Connect a 3 A fused jumper wire between the low control circuit terminal 2 and B+.
  10. Verify the Fuel Pressure Regulator 1 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 X3 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.
    • Go to next step: If Malfunction is displayed 
  11. Test or replace the G18 High Pressure Fuel Pump.
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