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Home >> Chevrolet >> 2023 >> Tahoe SSV >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 7 (Engine Controls And Fuel - 3.0L (Lm2) Diesel - Diagnostic Information And Procedures (3 Of 5)) >> Diagnostic Information and Procedures >> DTC P04DB, P04E2, P04E3, or P04FB >> Circuit/System Verification

Circuit/System Verification

WARNING: This page is about a different variant/trim than selected.
  1. Ignition - On/Vehicle - In Service Mode
  2. Verify DTC P0651 is not set.
    • Go to next step: If the DTC is not set 
  3. Verify the scan tool parameter: Crankcase Ventilation Hose Connection Pressure Sensor = -6.00 to 6.00 kPa (-0.80 to 0.80 PSI)
    • If not between -6.00 and 6.00 kPa (-0.80 and 0.80 PSI) 

      Refer to: Circuit/System Testing

    • Go to next step: If between -6.00 and 6.00 kPa (-0.80 and 0.80 PSI) 
  4. Verify the scan tool parameter: Crankcase Ventilation Hose Connection Pressure Sensor = -0.63 to 0.63 kPa (-0.09 to 0.09 PSI)
    • If not between -0.63 and 0.63 kPa (-0.09 and 0.09 PSI) 
    1. Ignition/Vehicle - Off
    2. Remove the component: B321 Crankcase Pressure Sensor - Leave the electrical connector connected.
    3. Ignition - On/Vehicle - In Service Mode
    4. Verify the scan tool parameter: Crankcase Ventilation Hose Connection Pressure Sensor = -0.63 to 0.63 kPa (-0.09 to 0.09 PSI)
      • If not between -0.63 and 0.63 kPa (-0.09 and 0.09 PSI)

        Replace the component: B321 Crankcase Pressure Sensor

      • Go to next step: If between -0.63 and 0.63 kPa (-0.09 and 0.09 PSI)
    5. Refer to step 8
    • Go to next step: If between -0.63 and 0.63 kPa (-0.09 and 0.09 PSI) 
  5. Engine - Idling
    6. NOTE:

    Using the scan tool line graph function may make it easier to identify if the value changes.

  6. Verify the scan tool parameter: Crankcase Ventilation Hose Connection Pressure Sensor = The value should change with accelerator pedal input.
    • If the parameter value does not change 

      Refer to: Circuit/System Testing

    • Go to next step: If the parameter value changes 
  7. Verify the scan tool parameter: Crankcase Ventilation Hose Connection Pressure Sensor = The value should not spike or drop out.

    Perform the action while monitoring the parameter:

    • Wiggle the harness and connector: B321 Crankcase Pressure Sensor
    • Wiggle the harness and connector: K20 Engine Control Module
    • If the value spikes or drops out 

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

    • Go to next step: If the value does not spike or drop out 
  8. Verify the following conditions do not exist:
    • Positive Crankcase Ventilation System - Hoses/Lines
      • Leaking - Loose Clamps/Visible Damage
      • Restricted - Collapsed/Kinked
    • B65 Intake Manifold Pressure and Air Temperature Sensor - Leaking@O-Ring - Missing/Visible Damage
    • B321 Crankcase Pressure Sensor - Leaking@O-Ring - Missing/Visible Damage
    • Air Cleaner Element - Dirty/Missing/Restricted
    • Intake Air Duct & Intake Manifold - Cracked/Loose Clamps/Restricted/Visible Damage - Refer to: Intake Manifold Replacement - Cleaning and Inspection Procedure - Conditional
    • Oil consumption
    • If a condition exists 

      Repair or replace as necessary

    • Go to next step: If no condition exists 
  9. 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 

      Repeat the procedure starting at step 3

    • Go to next step: If the DTC is not set 
  10. All OK.
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