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Home >> Chevrolet >> 2020 >> Express 2500 LS, 6.0L Eng VIN G >> Repair and Diagnosis >> External Pages >> Different car >> Section 92 (Engine Controls And Fuel - 2.8L (LWN) Diesel - Diagnostic Information And Procedures (1 Of 3)) >> Diagnostic Information and Procedures >> DTC P0300-P0304 >> Circuit/System Verification

Circuit/System Verification

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.
  1. Engine - Idling
  2. Verify there is no abnormal noise from the component: Engine
    • Go to next step: If no abnormal noise is present 
  3. Perform the scan tool learn/reset function: Crankshaft Position Variation Learn
  4. Verify there are no DTCs set related to the following system/component:
    • B23 Camshaft Position Sensor
    • B26 Crankshaft Position Sensor
    • E12 Glow Plug
    • Q17 Fuel Injector
    • Fuel System
    • Mechanical Condition
    • Go to next step: If a related DTC is not set 
  5. Verify the scan tool parameter: Cylinder 1 - 4 Current Misfire Counter = Does not Increment
    • If the parameter value increments 

      Refer to: Circuit/System Testing

    • Go to next step: If the parameter value does not increment 
    6. NOTE:

    The scan tool control function disables the following component(s) for 30 s when activated: Q17 Fuel Injector

  6. Perform the scan tool control function: Cylinder Power Balance - Enable

    Verify the sound of the engine changes the same way when turning off each individual injector.

    • If the engine sound does not change the same way for one or more cylinders 

      Refer to: Circuit/System Testing

    • Go to next step: If the engine sound changes the same way for all cylinders 
  7. Verify the scan tool parameter: Cylinder 1 - 4 Current Misfire Counter = Does not Increment

    Perform the action while monitoring the parameter:

    • Wiggle the harness and connector: K20 Engine Control Module
    • Wiggle the harness and connector: Q17 Fuel Injector
    • If the parameter value increments 

      Repair as necessary - Wiring / Terminal(s) / Electrical Connector(s)

    • Go to next step: If the parameter value does not increment 
  8. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

    Verify the DTC does not set.

    • If the DTC sets 

      Refer to: Circuit/System Testing

    • Go to next step: If the DTC does not set 
  9. All OK.
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