P0446

DESCRIPTION
A RESTRICTED or BLOCKED EVAP VENT PATH is detected by the Powertrain Control Module (PCM) monitoring the fuel tank pressure during normal operation. The PCM commands the EVAP vent Valve OFF (open), and the EVAP canister purge Valve ON (open). The fuel tank pressure should remain low as vacuum is drawn on the EVAP system. If the Vent path is blocked or restricted, the vacuum level will increase and DTC P0446 will set.

CONDITIONS FOR RUNNING THE DTC
^ DTC P0107, P0108, P0110, P0112, P0113, P0115, P0117, P0118, P0121, P0122, P0123, P0125, P0440, P0442, P0443, P0449, P0452, P0453, P1106, P1107, P1111, P1112, P1114, P1115, P1121 or P1122 are not set.
^ The system voltage is between 10-18 volts.
^ The startup ECT is between 4-30°C (39-86°F).
^ The startup IAT is between 4-30°C (39-86°F).
^ The fuel tank level is between 30-85 percent.
^ The Barometric Pressure (BARO) is more than 75 kPa.
^ The Vehicle Speed Sensor (VSS) is less than 121 kh/m (75 mph).

CONDITIONS FOR SETTING THE DTC
^ Fuel tank pressure is less than -10 inch H2O.
^ The condition is present for as long as 30 seconds.

ACTION TAKEN WHEN THE DTC SETS
^ The PCM will illuminate the Malfunction Indicator Lamp (MIL) during the second consecutive trip in which the diagnostic test has run and failed.
^ The PCM will store conditions which were present when the DTC set as Freeze Frame and Failure Records data.

CONDITIONS FOR CLEARING THE MIL/DTC
^ The Powertrain Control Module (PCM) will turn OFF the MIL during the first trip in which the diagnostic has been run and passed.
^ The history DTC will clear when the PCM turns OFF the MIL.
^ The DTC can be cleared by using the scan tool.

DIAGNOSTIC AIDS
The EVAP system tests run when the engine is first started and meets the conditions for running the DTC. An intermittent condition could be caused by a damaged EVAP Vent housing, a temporary blockage at the EVAP vent Valve inlet or a pinched vent hose. A blockage in the vent system will also cause a poor fuel fill problem. To repair a blockage in the EVAP system. Refer to Evaporative Emission (EVAP) System Cleaning. Service and Repair

TEST DESCRIPTION

Steps 1-4:

Steps 5-13:

The number below refers to the step number on the diagnostic table.
4. This test determines if the failure is present or intermittent.