P0446

DTC P0446

SYSTEM DESCRIPTION
This DTC tests the evaporative emission (EVAP) system for a restricted or blocked EVAP vent path. The control module commands the EVAP canister purge solenoid valve Open and the EVAP canister vent solenoid valve Closed. This allows vacuum to be applied to the EVAP system. Once a calibrated vacuum level has been reached, the control module commands the EVAP canister purge solenoid valve Closed and the EVAP canister vent solenoid valve Open.

The control module monitors the fuel tank pressure (FTP) sensor for a decrease in vacuum. If the vacuum does not decrease to near 0 inches H2O in a calibrated time, this DTC sets.




The table illustrates the relationship between the ON and OFF states, and the Open or Closed states of the EVAP canister purge and vent solenoid valves.

CONDITIONS FOR RUNNING THE DTC
- DTC P0101, P0102, P0103, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0125, P0221, P0222, P0223, P0440, P0442, P0443, P0449, P0451, P0452, P0453, P0458, P0459, P0496, P0498, P0499, P0500, P0560, P0562, P0563, P2122, P2123, P2127, P2128, P2138 are not set.
- The battery voltage is between 10.5-18 volts.
- The barometric pressure (BARO) is more than 68 kPa.
- The fuel level is between 15-85 percent.
- The engine coolant temperature (ECT) is between 4-65°C (39-149°F).
- The intake air temperature (IAT) is between 2-32°C (36-90°F).
- The start-up ECT and IAT are within 9°C (16°F) of each other.
- The vehicle speed sensor (VSS) is 0 km/h (0 mph).
- The fuel tank pressure is between -19 and +7.5 mm Hg (-10 and +4 in H2O).
- The engine is idling.
- The engine is operating in Closed Loop.

CONDITIONS FOR SETTING THE DTC
- The FTP is less than -10 inches H2O.
- The condition is present for 30 seconds.

ACTION TAKEN WHEN THE DTC SETS
- The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
- The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

CONDITIONS FOR CLEARING THE MIL/DTC
- The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
- A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
- A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
- Clear the MIL and the DTC with a scan tool.

TEST

Steps 1-3:

Steps 4-5:

Steps 6-12:

Steps 13-14: