2010 Cadillac CTS Sedan AWD V6-3.6L Page 1411
DTC P0446
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic System
Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Strategy Based Diagnosis) for an
overview of the diagnostic approach.
* Diagnostic Procedure Instructions (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic Procedure
Instructions) provides an overview of each diagnostic category.
DTC Descriptor
DTC P0446
- Evaporative Emissions (EVAP) Vent System Performance
Typical Scan Tool Data
Circuit/System Description
This DTC tests the evaporative emission (EVAP) system for a restricted or blocked EVAP vent path that would cause excess amounts of vacuum to
be developed in the EVAP system. With the purge valve open and the canister vent valve open, if the EVAP system vacuum goes above a
calibrated threshold, the test will fail.
Conditions for Running the DTC
* DTCs P0106, P0107, P0108, P0116, P0117, P0118, P0120, P0121, P0122, P0123, P0220, P0222, P0223, P0442, P0443, P0449, P0451,
P0452, P0453, P0454, P0464, P0496, P0608, P0609, P0641, P0651, P1516, P2101, P2119, P2120, P2122, P2123, P2125, P2127, P2128,
P2135, P2138 are not set.
* The ignition voltage is between 11-18 V.
* The barometric pressure (BARO) is more than 65 kPa.
* The fuel level is between 11-88 %.
* DTC P0446 runs once per cold start when the above conditions are met.
Conditions for Setting the DTC
* The fuel tank vacuum is greater than -12 in. H2O vacuum for 5 s.
OR
* The FTP is less than -2.5 in. H2O or more than +5 in. for 60 s after a cold start.
Action Taken When the DTC Sets
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 will 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
