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John, Master A.S.E Automotive technician
Category: Chevy
Satisfied Customers: 9176
Experience:  A.S.E MasterTechnician A1-A8 w/L1,38 years experience General Motors Master Technician
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i have a 2007 chevy avalanche that has this code p0449 what

Resolved Question:

i have a 2007 chevy avalanche that has this code p0449 what must i do to fix this code
Submitted: 4 years ago.
Category: Chevy
Expert:  John replied 4 years ago.

Hello,

 

This is usually caused by a faulty canister vent valve.here is some info to help you.

 

This condition may be caused by water spray that is generated by the rear wheels. The EVAP CVS valve draws fresh air into the EVAP system around a mushroom cap covered opening in the conduit that is mounted near the top of the fuel filler pipe. Under certain operating conditions, the moisture is ingested into the fresh air intake conduit opening, and is carried down though the conduit to the EVAP CVS valve causing corrosion in the CVS valve, and restrictions in the fresh air intake path, when the valve is in the closed position.

The water also collects in the CVS valve cyclonic filter in order to protect the EVAP canister. However if the capacity of the cyclonic filter is exceeded, this may result in water entering the EVAP canister and cause an additional restriction during refueling.

 

  • Turn OFF the ignition, and all electrical components, including the scan tool if connected.
  • Remove the fuel fill cap.
    Object Number: 853731  Size: SH

  • Remove the fuel tank filler housing to body TORX® screws (1) and retainer (2).
  • Raise and support the vehicle at the appropriate height, in order to gain access to the spare tire assembly. Refer to Lifting and Jacking the Vehicle in SI.
    Object Number:(NNN) NNN-NNNN Size: SH

  • Remove the spare tire and wheel assembly.
    Object Number:(NNN) NNN-NNNN Size: SH

  • Disconnect the chassis wiring harness electrical connector (1) from the CVS valve.
    Object Number:(NNN) NNN-NNNN Size: SH

    Important: Clean the EVAP line connections and surrounding areas prior to disconnecting, in order to avoid possible EVAP system contamination.

  • Disconnect the CVS valve quick connect fitting (1) from the EVAP canister, and disconnect the fuel filler pipe EVAP line quick connect fitting (3) from the CVS valve. Refer to Plastic Collar Quick Connect Fitting Service in SI.
    Object Number:(NNN) NNN-NNNN Size: SH

  • Disengage the retainer (1) securing the CVS valve to the bracket, and remove the CVS valve.
    Object Number:(NNN) NNN-NNNN Size: SH

  • Remove the zip ties (1) as needed, and the CVS valve black conduit and mushroom cap (2).
  • Leave attached a 50 mm (2 in) piece of the CVS valve black conduit to the plastic collar quick connect fitting that was disconnected from the CVS valve.
  • Securely connect a 1.22 m (48 in) length of 19 mm (0.75 in) inside diameter heater hose to the 50 mm (2 in) piece of black conduit that is connected to the plastic collar quick connect fitting for the CVS valve.
  • Install and fully seat the revised CVS valve filter into the open end of the 1.22 m (48 in) heater hose that is attached to the 50 mm (2 in) piece of black conduit.
    Object Number:(NNN) NNN-NNNN Size: SH

  • Lower the fuel tank filler pipe housing (3), and the fuel tank fill hose (4).
    Object Number:(NNN) NNN-NNNN Size: SH

  • Add two holes to the fuel tank filler pipe housing, approximately 25 mm (1 in) apart as indicated in the illustration, in order to secure the heater hose, and CVS valve filter with a zip tie to the housing.
    Object Number:(NNN) NNN-NNNN Size: SH

    Note: Observe the proper orientation of the CVS valve filter (1) in the illustration.

  • Secure the CVS valve filter (1) and the CVS valve heater hose to the fuel tank filler pipe housing with a zip tie as indicated in the illustration. Position the zip tie so that sharp surfaces are not present within the fuel cap area of the housing.
  • Raise the fuel tank filler pipe housing, and the fuel tank fill hose back to the original position, and install the zip ties that were removed from their previous locations. Verify that kinks do not exist at any point in the heater hose.
    Object Number:(NNN) NNN-NNNN Size: SH

  • Install the CVS valve and connect the electrical connector. Connect the CVS valve quick connect fitting (1) to the EVAP canister, and connect the fuel filler pipe EVAP line quick connect fitting (3) to the CVS valve. Refer to Plastic Collar Quick Connect Fitting Service in SI.
  • Install the spare tire and wheel assembly.
  • Lower the vehicle.
    Object Number: 853731  Size: SH

  • Install the fuel tank filler housing to body TORX® screws (1) and retainer (2).

    Tighten
    Tighten the screws to 2.3 N·m (20 lb in).

  • Install the fuel fill cap.
  • With a scan tool clear any DTCs that may be present.
  • Parts Information

    Part Number

    Description

    Qty

    Material Allowance

    25962085

    Valve, EVAP EMIS CNSTR CONT

    (Short Wheelbase)

    1

    --

    25962086

    Valve, EVAP EMIS CNSTR CONT

    (Long Wheelbase)

    1

    --

    19208702

    Filter, EVAP EMIS CNSTR VENT VLV

    1

    --

    12368236 or Equivalent

    Heater Hose 7.62 m (25 ft) Length, 19 mm (0.75 in) ID Roll

    1

    USD $24.49 (per 1.22 m (48 in) Length)

    John, Master A.S.E Automotive technician
    Category: Chevy
    Satisfied Customers: 9176
    Experience: A.S.E MasterTechnician A1-A8 w/L1,38 years experience General Motors Master Technician
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