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Home >> Chevrolet >> 2020 >> Express 2500 LS, 6.0L Eng VIN G >> Repair and Diagnosis >> External Pages >> Different car >> Section 1 (Displays And Gauges) >> Diagnostic Information and Procedures >> Fuel Gauge Malfunction >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2019 GMC Savana 3500, 2019 GMC Savana 2500, 2019 Chevrolet Express 3500, and 2019 Chevrolet Express 2500. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:

Circuit/System Verification must be performed before proceeding with Circuit/System Testing.

  1. Ignition OFF/Vehicle OFF and all vehicle systems OFF, disconnect the harness connector at the A7 Fuel Pump and Level Sensor assembly. It may take up to 2 min for all vehicle systems to power down.
  2. Test for less than 10 Ω between the low reference circuit terminal 6 and ground.
    • If 10 Ω or greater 
    1. Ignition OFF/Vehicle OFF, disconnect the harness connector at the K20 Engine 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, replace the K20 Engine Control Module.
    • Go to next step: If less than 10 Ω 
  3. Ignition ON/Vehicle in Service Mode.
  4. Verify the scan tool Fuel Level Sensor parameter is greater than 4.8 V.
    • If 4.8 V or less 
    1. Ignition OFF/Vehicle OFF, disconnect the harness connector at the K20 Engine Control Module.
    2. Test for infinite resistance between the signal circuit terminal 5 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 greater than 4.8 V 
  5. Install a 3 A fused jumper wire between the signal circuit terminal 5 and the low reference circuit terminal 6.
  6. Verify the scan tool Fuel Level Sensor parameter is less than 0.2 V.
    • If 0.2 V or greater 
    1. Ignition OFF/Vehicle OFF, disconnect the harness connector at the K20 Engine Control Module, ignition ON.
    2. Test for less than 1 V between the signal circuit and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • Go to next step: If less than 1 V
    3. Ignition OFF/Vehicle OFF
    4. Test for less than 2 Ω in the signal 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 less than 0.2 V 
  7. Test or replace the fuel level sensor
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