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Home >> Chevrolet >> 2017 >> City Express LS >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls And Fuel - 2.0L >> Diagnostic Information And Procedures >> DTC P0456 >> Circuit/System Testing
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Circuit/System Testing

  1. Check the fuel filler cap and seals for damage and proper installation
    • If cap is loose, tighten cap until a ratcheting sound is heard.
    • If damage or wear is found, replace the fuel filler cap.
    • If no problems are found with the fuel filler cap.
  2. Raise the vehicle and disconnect the EVAP filter inlet hose at the quick connect fitting and plug the inlet to the filter with a J-41413-323  .
  3. Lower the vehicle and connect the GE 41413-A  to the purge line on the EVAP canister side of the EVAP purge solenoid valve using the J-41413-311  EVAP plug adapter.
  4. Use the GE 41413-A  to introduce nitrogen and fill the EVAP system until the floating indicator stabilizes. It may take several minutes for the float to stabilize.
  5. Use the flow meter on GE 41413-A  , calibrated to 0.51 mm (0.020 in), to determine that there is no leak in the evaporative emission system.
    • If a leak is detected, use the GE 41413-A  to apply smoke to the EVAP system at the purge tube until the leak is located using the GE-41413-SPT  white light.
    • If no leak is detected
  6. Check the EVAP Canister Vent Solenoid Valve. refer to DTC P0447 or P0448 .
  7. Check EVAP canister. Refer to Component Testing.
  8. Check the EVAP Purge Solenoid Valve operation. Refer to DTC P0444 or P0445 .
  9. Check all EVAP hoses for damage or obstruction and repair or replace as necessary.