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Home >> Chevrolet >> 2021 >> Blazer RS, FWD >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 12 (Engine Controls And Fuel - 2.0L (LSY) - Diagnostic Information And Procedures (2 Of 2)) >> Diagnostic Information and Procedures >> DTC P0451-P0454 >> Circuit/System Verification

Circuit/System Verification

WARNING: This page is about a different variant/trim than selected.
WARNING:

Refer to: Fuel and Evaporative Emission Pipe Warning

CAUTION:

Refer to: Clean, Dry, Low Pressure Gas Source Caution

  1. Ignition - On/Vehicle - In Service Mode
  2. Verify DTC P1176 is not set.
    • Go to next step: If the DTC is not set 
  3. Verify with the customer the following did not exist: Poor fuel fill quality
    • If a condition exists 
    1. Ignition/Vehicle - Off
    2. Verify the condition does not exist with the component and repair as necessary:
      1. Evaporative Emission Vent Filter or Evaporative Emission Canister Air Inlet Hose - Blocked/Dirty/Ice/Restricted/Visible Damage
      2. Q13 Evaporative Emission Vent Solenoid Valve - Blocked/Restricted/Visible Damage
      3. Evaporative Emission Canister Vent Hose or Pipe - Blocked/Kinked/Restricted/Visible Damage
      4. Evaporative Emission Canister - Restricted/Visible Damage
      5. Evaporative Emission Hose - Kinked/Restricted/Visible Damage
      6. Evaporative Emission Pipe - Kinked/Restricted/Visible Damage
    • Go to next step: If no condition exists 
  4. Verify the following conditions do not exist:
    • Evaporative Emission Canister - Restricted/Visible Damage
    • Evaporative Emission Hose - Kinked/Restricted/Visible Damage
    • Evaporative Emission Pipe - Kinked/Restricted/Visible Damage
    • If a condition exists 

      Repair or replace as necessary

    • Go to next step: If no condition exists 
  5. Disconnect the component: Quick Connect Fitting @ Q12 Evaporative Emission Purge Solenoid Valve
    6. NOTE:

    To help with installing the tool, the fasteners from the component bracket may need to be removed: G58 Evaporative Emission Canister Purge Pump

  6. Install - CH-52519 EVAP Service Port Access Tool - Between: Evaporative Emission Canister Purge Tube & Q12 Evaporative Emission Purge Solenoid Valve
  7. Install - GE-41413-A/B Evaporative Emissions System Tester (EEST) - Hose @ CH-52519 EVAP Service Port Access Tool
  8. Ignition - On/Vehicle - In Service Mode
  9. Perform the following action:
    1. Perform the scan tool function: Evaporative Emission Canister Vent Valve - Not Venting
    2. Select - Nitrogen @ GE-41413-A/B Evaporative Emissions System Tester (EEST)
    3. Press and release the switch: Remote Switch @ GE-41413-A/B Evaporative Emissions System Tester (EEST) - Special Tool = On or Activated

      Use the tool to achieve a gauge reading of 9.3 mmHg (5.0 in H2O)

    4. Verify the scan tool parameter: Fuel Tank Pressure Sensor @ K20 Engine Control Module & Gauge @ GE-41413-A/B Evaporative Emissions System Tester (EEST) = Within 1.9 mmHg (1.0 in H2O) of each other
    • If not within 1.9 mmHg (1.0 in H2O) of each other 

      Replace the component: B150 Fuel Tank Pressure Sensor

    • Go to next step: If within 1.9 mmHg (1.0 in H2O) of each other 
  10. Perform the scan tool function: Evaporative Emission Canister Vent Valve - Venting

    Verify the scan tool parameter: Fuel Tank Pressure Sensor @ K20 Engine Control Module = -1.9 to 1.9 mmHg (-1.0 to 1.0 in. H2O) - Within 3 s

    • If not between -1.9 to 1.9 mmHg (-1.0 to 1.0 in. H2O) or Does not decrease within the specified time 
    1. Ignition/Vehicle - Off
    2. Verify the condition does not exist with the component and repair as necessary:
    • Evaporative Emission Canister - Incorrect connection/Restricted/Visible Damage
    • Evaporative Emission Hose - Defective/Incorrect connection/Kinked/Restricted/Visible Damage
    • Evaporative Emission Pipe - Defective/Incorrect connection/Kinked/Restricted/Visible Damage
    • Go to next step: If between -1.9 to 1.9 mmHg (-1.0 to 1.0 in. H2O) & Decreases within the specified time 
  11. Perform the following action:
    • {Cap Type Fuel Fill} Remove - Fuel Tank Filler Cap
    • {Capless Type Fuel Fill} Install - GE-41415-60 Engine Induction System Leak Test Adapter/Capless Fuel Fill Adapter @ Door @ Fuel Tank Filler Pipe
  12. Ignition - On/Vehicle - In Service Mode
  13. Verify the scan tool parameter: Fuel Tank Pressure Sensor @ K20 Engine Control Module = 1.3 to 1.7 V
    • If not between 1.3 and 1.7 V 

      Refer to: Circuit/System Testing

    • Go to next step: If between 1.3 and 1.7 V 
  14. Verify the scan tool parameter: Fuel Tank Pressure Sensor @ K20 Engine Control Module = The parameter value should not change.

    Perform the action while monitoring the parameter:

    • Wiggle the harness and connector: B150 Fuel Tank Pressure Sensor
    • Wiggle the harness and connector: K20 Engine Control Module
    • If the parameter value changes 

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

    • Go to next step: If the parameter value does not change 
  15. 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 is not set 
  16. All OK.
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