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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 >> Fuel Injector Circuit Diagnosis >> Circuit/System Testing

Circuit/System Testing

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  1. Ignition OFF, all vehicle systems OFF, disconnect the X3 harness connector at the K20 Engine Control Module. It may take up to 2 min for all vehicle systems to power down.
  2. Test for infinite resistance between the appropriate Q17 Fuel Injector control + circuit and ground.
    • If less than infinite resistance 
    1. Disconnect the harness connector of the Q17 Fuel Injector.
    2. Test for infinite resistance between the Q17 Fuel Injector control + circuit and ground.
      • If infinite resistance
    3. Test for infinite resistance between the Q17 Fuel Injector control - circuit and ground.
      • If less than infinite, repair the short to ground in the circuit.
      • If infinite, replace the Q17 Fuel Injector.
    • Go to next step: If infinite resistance 
  3. Ignition ON.
  4. Test for less than 1 V between the Q17 Fuel Injector control + circuit and ground.
    • If 1 V or greater 
    1. Disconnect the harness connector of the Q17 Fuel Injector, ignition ON.
    2. Test for less than 1 V between the Q17 Fuel Injector control + circuit and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • If less than 1 V, repair the short to voltage on the control - circuit.
    • Go to next step: If less than 1 V 
  5. Ignition OFF.
  6. Test for less than 3 Ω between the Q17 Fuel Injector control + circuit and control - circuit.
    • If 3 Ω or greater 
    1. Disconnect the harness connector of the Q17 Fuel Injector.
    2. Test for less than 2 Ω on the control + circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω
    3. Test for less than 2 Ω on the 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 Q17 Fuel Injector.
    • Go to next step: If less than 3 Ω 
  7. Replace the K20 Engine Control Module.
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