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Home >> Chevrolet >> 2018 >> Suburban 3500 HD LT >> Repair and Diagnosis >> External Pages >> Different car >> Section 2 (Engine Controls And Fuel - 5.3L (L83) Or 6.2L (L86) - DTC P0010 To DTC P0442) >> Diagnostic Information And Procedures >> DTC P0231, P0232 Or P023F: Fuel Pump Control Circuit >> Circuit/System Testing

Circuit/System Testing

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2018 GMC Yukon XL, 2018 GMC Yukon, 2018 Chevrolet Tahoe, 2018 Chevrolet Suburban, and 2018 Cadillac Escalade ESV. 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 G12 Fuel Pump. Connect a test lamp between battery positive voltage and the G12 Fuel Pump harness connector terminal 2. It may take up to 2 min for all vehicle systems to power down.
  2. Verify the test lamp illuminates.
    • If the test lamp does not illuminate 
    1. Ignition OFF, disconnect the harness connector at the K111 Fuel Pump Driver Control Module.
    2. Test for less than 2 Ω in the low reference circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, refer to Component Testing  in this diagnostic.
    • Go to next step : If the test lamp illuminates 
  3. Ignition ON, connect a test lamp between the supply voltage circuit terminal 1 and the low reference circuit terminal 2.
  4. Verify the test lamp turns ON and OFF when commanding the Fuel Pump Enable On and Off with a scan tool.
    • If the test lamp is always OFF 
    1. Ignition OFF, disconnect the harness connector at the K111 Fuel Pump Driver Control Module.
    2. Test for infinite resistance between the supply voltage circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance
    3. Test for less than 2 Ω in the supply voltage 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 K111 Fuel Pump Driver Control Module.
    • If the test lamp is always ON 
    1. Ignition OFF, remove the test lamp, disconnect the harness connector at the K111 Fuel Pump Driver Control Module, ignition ON.
    2. Test for less than 1 V between the supply voltage 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 K111 Fuel Pump Driver Control Module.
    • Go to next step : If the test lamp turns ON and OFF 
  5. Test or replace the G12 Fuel Pump.
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