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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 Testing
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Circuit/System Testing

NOTE:

Perform the Circuit/System Verification before proceeding with the Circuit/System Testing.

Restriction

  1. With the engine running, the EVAP vent solenoid valve open, and the EVAP purge solenoid valve commanded 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 value, isolate the restriction by disconnecting one component at a time while the EVAP purge solenoid valve is commanded to 100 % and the vent valve is open.
  2. 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, inspect the components in the EVAP vent system for a restriction.

Fuel Tank Pressure Sensor

  1. Ignition OFF, disconnect the harness connector at the B150 fuel tank pressure sensor.
  2. Ignition OFF, all vehicle systems OFF, this may take up to 2 min, test for less than 5 Ω between the low reference circuit terminal and ground.
    • If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the B150 fuel tank pressure sensor.
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