P0446

Refer to Engine Controls Schematics Diagram, EVAP System Overview.

Diagnostic Chart (Part 1 Of 2):

Diagnostic Chart (Part 2 Of 2):

SYSTEM DESCRIPTION
The Evaporative Emissions (EVAP) system includes the following components:
^ The fuel tank
^ The EVAP vent valve
^ The fuel pipes and hoses
^ The fuel fill cap
^ The EVAP vapor pipes
^ The EVAP purge pipes
^ The EVAP canister
^ The EVAP canister purge valve

A restricted or blocked EVAP vent path is detected by monitoring the fuel tank pressure during normal operation, with the EVAP vent valve open, and the EVAP canister purge valve normal. With the EVAP vent valve open, the vacuum level in the system should be very low unless the vent path is blocked.

The following conditions will set DTC P0446:
^ A faulty or stuck closed EVAP vent valve
^ A plugged, kinked, or pinched vent hose
^ A shorted EVAP vent valve driver circuit
^ A plugged EVAP canister

CONDITIONS FOR RUNNING THE DTC
All conditions for P0440 and P0442 have been met and passed.

CONDITIONS FOR SETTING THE DTC
^ The fuel tank pressure is less than -10 in Hg.
^ The condition is present for up to 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 been run and failed.
^ The PCM will store conditions which were present when the DTC set as Freeze Frame and Failure Records data.
^ If the misfire is determined to be catalyst damaging, the PCM will flash the MIL.

CONDITIONS FOR CLEARING THE MIL/DTC
^ The PCM will turn OFF the MIL during the third consecutive 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
Check for the following conditions:
^ A kinked, pinched, or plugged vent hose.
^ A charcoal release from the EVAP canister.

Reviewing the Fail Records vehicle mileage since the diagnostic test last failed may help to determine how often the condition that caused the DTC to be set occurs. This may assist in diagnosing the condition.

TEST DESCRIPTION
The numbers below refer to the step numbers on the diagnostic table.
1. The Powertrain On Board Diagnostic (OBD) System Check prompts you to complete some basic checks and to store the Freeze Frame and Failure Records data on the scan tool if applicable.
5. This step tests the EVAP canister purge valve for a small vacuum source during non-purge.
7. This step tests the EVAP vent valve for a restriction or blockage.