DTC P0446 is a Type B DTC.
Conditions for Clearing the MIL/DTC
DTC P0446 is a Type B DTC.
Diagnostic Aids
* An intermittent condition could be caused by a damaged EVAP vent housing, a temporary blockage at the EVAP canister vent solenoid valve
inlet, or a pinched vent hose. A blockage in the vent system may also cause a poor fuel fill condition.
* An EVAP canister filter that is restricted can cause this DTC to set.
Reference Information
Schematic Reference
Engine Controls Schematics (See: Diagrams/Electrical Diagrams/Powertrain Management/System Diagram)
Connector End View Reference
Component Connector End Views (See: Diagrams/Connector Views)
Electrical Information Reference
* Circuit Testing (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Circuit
Testing/Circuit Testing)
* Testing for Intermittent Conditions and Poor Connections (See: Testing and Inspection/Component Tests and General Diagnostics/General
Electrical Diagnostic Procedures/Circuit Testing/Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Wiring
Repairs/Wiring Repairs)
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions (See: Diagnostic Trouble Code Descriptions/Powertrain Diagnostic Trouble Code
(DTC) Type Definitions)
Description and Operation
Evaporative Emission Control System Description (See: Powertrain Management/Computers and Control Systems/Description and
Operation/Evaporative Emission Control System Description)
Scan Tool Reference
Control Module References (See: Testing and Inspection/Programming and Relearning) for scan tool information
Circuit/System Verification
1. Ignition ON and fuel cap removed, verify that the Fuel Tank Pressure Sensor parameter is between 1.3-1.7 volts.
锟斤拷If not within the specified range, go to the fuel tank pressure sensor section in Circuit/System Testing.
2. Install the fuel cap.
3. With the engine running, the EVAP canister vent solenoid valve open, use a scan tool to command the EVAP canister purge solenoid valve
to 100 percent. The fuel tank vacuum should not increase to more than -15 mmHg (-8 inches H2O).
锟斤拷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 percent to 0 percent. The vacuum should decrease to near zero.
锟斤拷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.
Circuit/System Testing
Note: Perform the Circuit/System Verification before proceeding with the Circuit/System Testing.
Restriction
1. With the engine running, the EVAP canister vent solenoid valve open, and the EVAP canister purge solenoid valve commanded to 100
percent, the fuel tank vacuum should not increase to more than -15 mmHg (-8 inches H2O).
锟斤拷If the fuel tank vacuum is greater than the specified value, isolate the restriction by disconnecting one component at a time while the
EVAP canister purge solenoid valve is commanded to 100 percent and the vent valve is open.
