Silverado 2008

Evaporative Emissions (EVAP) Canister

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Location



Specific to:

Chevrolet Silverado 1500 2008

The Evaporative Emissions (EVAP) Canister is mounted on the side of the fuel tank or on the side of the frame rail near fuel tank, depending upon fuel tank size, cab style and engine configuration.

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Fig. Evaporative canister and related components extended cab with 26 gallon fuel tank-4.3L engines



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Fig. Evaporative canister and related components extended cab and crew cab with 26 gallon fuel tank-4.8L, 5.3L & 6.0L engines



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Fig. Evaporative canister and related components standard cab with 26 and 34 gallon fuel tanks-4.3L engines



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Fig. Evaporative canister and related components with 26 and 34 gallon fuel tanks-4.8L, 5.3L & 6.0L engines

Removal & Installation



Specific to:

Chevrolet Silverado 1500 2008

  1. Before servicing the vehicle, refer to the Precautions Section.
  2.  
  3. Disconnect the negative battery cable.
  4.  
  5. Raise and support the vehicle safely.
  6.  
  7. Disconnect the quick connect fittings.
  8.  
  9. Remove the canister retaining nut.
  10.  
  11. Remove the assembly from its mounting.
  12.  
  13. If replacing the canister, remove the bracket.

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    Fig. EVAP canister and related components-type one



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    Fig. EVAP canister and related components-type two



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    Fig. EVAP canister bracket removal



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    Fig. Evaporative canister and related components extended cab with 26 gallon fuel tank-4.3L engines



    Click image to see an enlarged view

    Fig. Evaporative canister and related components extended cab and crew cab with 26 gallon fuel tank-4.8L, 5.3L & 6.0L engines



    Click image to see an enlarged view

    Fig. Evaporative canister and related components standard cab with 26 and 34 gallon fuel tanks-4.3L engines



    Click image to see an enlarged view

    Fig. Evaporative canister and related components with 26 and 34 gallon fuel tanks-4.8L, 5.3L & 6.0L engines

  14.  

To install:


NOTE
Be sure to use new fasteners, as required.

  1. Position the canister on its mounting.
  2.  
  3. Continue the installation in the reverse order of the removal procedure.
  4.  

Operation



Specific to:

Chevrolet Silverado 1500 2008

The Evaporative Emissions (EVAP) Canister is the primary component in the Evaporative Emission (EVAP) Control System that prevents the evaporation of unburned fuel vapors (Hydrocarbons) from being released into the atmosphere. The EVAP canister contains a charcoal element for the filtering of hydrocarbons, and the filtered Carbon Dioxide (CO2) is then vented to atmosphere when the vehicle is not in operation. The canister also contains a number of ports, which provide for the redistribution of hydrocarbons into the fuel tank when the vehicle is in operation through the purge control system.

Testing



Evaporative Emission Control System (EVAP) Diagnostics

Specific to:

Chevrolet Silverado 1500 2008

When testing the EVAP system for proper operation, there should always be a pressure differential between the fuel tank pressure and atmospheric pressure. If any of the tests reveal a pressure differential of less than .02- Hg (.067 kPa/.5mm Hg), the Powertrain Control Module (PCM) will interpret this condition as a leak.

  1. Verify the condition of the EVAP system by performing the following visual inspections:

    Ensure that the fuel filler cap is installed and properly secured.
     
    Inspect the charcoal canister for physical damage such as cracks, broken or cracked fittings, damage from road debris, or rodent damage.
     
    Inspect all EVAP control devices (EVAP and purge control system monitors, controllers, and actuators) for physical damage such as cracks, broken or cracked fittings, damage from road debris, or rodent damage.
     
    Inspect all hoses and vacuum line connections for proper routing and placement.
     
    Inspect all electronic control devices for proper electrical connections.
     
    Inspect the condition of all fittings and seals for damage, drying, or wear.
     
    Inspect the condition of all hoses and vacuum lines for displacement, damage, or wear.
     

  2.  

If any physical defects are evident, verify the operation of any questionable components before replacement.

  1. Verify the operation of the EVAP system by performing any or all the following tests:

    Using a suitable scan tool, perform an actuator (active) test to verify the correct operation of EVAP control devices (EVAP and purge control system monitors, controllers, and actuators).
     
    Using a smoke machine, verify that the EVAP system does not exhibit any physical leaks.
     
    Using a suitable EVAP system pressure tester, verify that the EVAP system is properly sealed against positive and negative pressure.
     
    Using a suitable EVAP system pressure tester along with a suitable scan tool, monitor the EVAP pressure under positive and negative pressure conditions.
     

  2.  

Related Diagnostic Trouble Codes (DTC)

Specific to:

Chevrolet Silverado 1500 2008



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Fig. Related Diagnostic Trouble Codes

 
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