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Home >> Chevrolet >> 2011 >> Caprice >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls And Fuel - 6.0L - DTC Diagnostics And Troubleshooting >> Diagnostic Information and Procedures >> DTC P0446 >> Circuit/System Verification

Circuit/System Verification

  1. Ignition ON and fuel cap removed, verify that the FTP sensor parameter is between 1.3-1.7 V.
  2. Install the fuel cap.
  3. With the engine running, the EVAP vent solenoid valve open, use a scan tool to command the EVAP purge solenoid valve to 100 %. The fuel tank vacuum should not increase to more than -15 mm Hg (-8 in H2O).
    • If the fuel tank vacuum is greater than the specified range, go to the restriction section in Circuit/System Testing .
  4. Using the scan tool, decrease the canister purge duty cycle from 100 % to 0 %. The vacuum should decrease to near zero.
    • If the fuel tank vacuum does not return to zero or appears to decrease too slowly go to the restriction section in Circuit/System Testing .
  5. 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.
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