Circuit/System Testing

2019 Chevrolet Express 2500 Base, Van Cargo Extended, 6.0L Eng VIN GSECTION Circuit/System Testing
WARNING: This page is about a different variant/trim than selected.
    NOTE:
    • An empty fuel tank or a defective fuel pump may cause DTCs to set.
    • If set only as a history DTC, do not replace any component.
    • Verify the fuel tank is not empty before proceeding.
    • It may take up to 2 min for all vehicle systems to power down before an accurate ground or low reference circuit continuity test can be performed.
  1. Ignition/Vehicle & All vehicle systems - Off
  2. Disconnect the electrical connector: B47 Fuel Pressure Sensor
  3. Test for less than 10 ohms between the test points: Low Reference circuit terminal 2 & Ground
    • If 10 ohms or greater 
    1. Disconnect the electrical connector: K38 Chassis Control Module
    2. Test for less than 2 ohms between the test points: Low Reference circuit terminal 2 @ Component harness & Terminal 23 @ Control module harness
      • If 2 ohms or greater - Repair the open/high resistance in the circuit.
      • If less than 2 ohms - Replace the component: K38 Chassis Control Module
    • Go to next step: If less than 10 ohms 
  4. Ignition - On / Vehicle - In Service Mode
  5. Test for 4. 8 to 5. 2 V between the test points: 5 V Reference circuit terminal 3 & Low Reference circuit terminal 2
    • If less than 4. 8 V 
    1. Ignition/Vehicle - Off
    2. Disconnect the electrical connector: K38 Chassis Control Module
    3. Test for infinite resistance between the test points: 5 V Reference circuit terminal 3 @ Component harness & Ground
      • If less than infinite resistance - Repair the short to ground on the circuit.
      • Go to next step: If infinite resistance
    4. Test for less than 2 ohms between the test points: 5 V Reference circuit terminal 3 @ Component harness & Terminal 22 @ Control module harness
      • If 2 ohms or greater - Repair the open/high resistance in the circuit.
      • If less than 2 ohms - Replace the component: K38 Chassis Control Module
    • If greater than 5. 2 V 
    1. Ignition/Vehicle - Off
    2. Disconnect the electrical connector: K38 Chassis Control Module
    3. Ignition - On / Vehicle - In Service Mode
    4. Test for less than 1 V between the test points: 5 V Reference circuit terminal 3 @ Component harness & Ground
      • If 1 V or greater - Repair the short to voltage on the circuit.
      • If less than 1 V - Replace the component: K38 Chassis Control Module
    • Go to next step: If between 4. 8 and 5. 2 V 
  6. Verify the scan tool parameter: Fuel Pressure Sensor - Voltage = Less than 1 V
    • If 1 V or greater 
    1. Ignition/Vehicle - Off
    2. Disconnect the electrical connector: K38 Chassis Control Module
    3. Ignition - On / Vehicle - In Service Mode
    4. Test for less than 1 V between the test points: Signal circuit terminal 1 @ Component harness & Ground
      • If 1 V or greater - Repair the short to voltage on the circuit.
      • If less than 1 V - Replace the component: K38 Chassis Control Module
    • Go to next step: If less than 1 V 
  7. Connect a 3 A fused jumper wire between the test points: Signal circuit terminal 1 & 5 V Reference circuit terminal 3
  8. Verify the scan tool parameter: Fuel Pressure Sensor - Voltage = Greater than 4. 8 V
    • If 4. 8 V or less 
    1. Ignition/Vehicle - Off & Remove - Jumper wire(s)
    2. Disconnect the electrical connector: K38 Chassis Control Module
    3. Test for infinite resistance between the test points: Signal circuit terminal 1 @ Component harness & Ground
      • If less than infinite resistance - Repair the short to ground on the circuit.
      • Go to next step: If infinite resistance
    4. Test for less than 2 ohms between the test points: Signal circuit terminal 1 @ Component harness & Terminal 10 @ Control module harness
      • If 2 ohms or greater - Repair the open/high resistance in the circuit.
      • If less than 2 ohms - Replace the component: K38 Chassis Control Module
    • Go to next step: If greater than 4. 8 V 
  9. Test or replace the component: K38 Chassis Control Module
RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • You smell fuel, burning insulation, or see smoke.
  • Brakes feel soft, pull hard to one side, or make grinding noises.
  • The engine overheats, stalls repeatedly, or misfires under load.
  • You are missing required tools, torque specs, or safe lifting equipment.
  • You are not confident in the next step or safety outcome.