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Makes 🢒 Saturn 🢒 2007 🢒 VUE - FWD 🢒 Diagnostic Navigation 🢒 Vehicle Diagnostic Information 🢒 DTC P0446
Table 1: DTC P0446 Evaporative Emission (EVAP) Vent System Performance

System Description

This diagnostic monitors the evaporative emission (EVAP) system for a restricted or blocked EVAP vent system. The control module commands the EVAP canister purge solenoid Open and the EVAP canister vent solenoid 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 Closed and the EVAP canister vent solenoid 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 following table illustrates the relationship between the ON and OFF states, and the Open or Closed states of the EVAP canister purge and vent valves.

Control Module Command

EVAP Canister Purge Solenoid

EVAP Canister Vent Solenoid

ON

Open

Closed

OFF

Closed

Open

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P0446 Evaporative Emission (EVAP) Vent System Performance.

Conditions for Running the DTC
    •  DTCs P0107, P0108, P0117, P0118, P0335, P0452, P0453, P0496, P0498, P0499, P1128, P1129, P2227, P2228, and P2229 are not set.
    • The battery voltage is more than 10 volts.
    • The fuel system is operating in closed loop.
    • The engine coolant temperature (ECT) is between 4-65°C (39-149°F) at start-up.
    • DTC P0446 runs once per drive cycle when the above conditions are met.

Conditions for Setting the DTC
    • The FTP is less than -13 inches H2O.
    • The condition is present for as long as 3 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.

Diagnostic Aids

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 condition.

DTC P0446 Evaporative Emission (EVAP) Vent System Performance

Step

Action

Values

Yes

No

Schematic Reference: Evaporative Emissions Hose Routing Diagram

1

Did you perform the Diagnostic System Check - Vehicle?

--

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

Inspect the evaporative emission (EVAP) system for the following conditions:

    • A damaged EVAP vent valve
    • A damaged EVAP canister

Did you find and correct the condition?

--

Go to Step 9

Go to Step 3

3
  1. Turn OFF the ignition.
  2. Disconnect the purge line from the EVAP canister purge solenoid.
  3. Turn ON the ignition, with the engine OFF.
  4. Observe the Fuel Tank Pressure parameter with a scan tool.

Is the Fuel Tank Pressure sensor parameter within the specified range?

-1 and +1  in H20

Go to Step 4

Go to Step 8

4
  1. Turn OFF the ignition.
  2. Remove the EVAP canister. Refer to Evaporative Emission Canister Replacement.
  3. Remove the EVAP vent valve from the EVAP canister. Refer to Evaporative Emission Canister Vent Solenoid Valve Replacement.
  4. With the EVAP canister removed from the vehicle, connect the EVAP vent valve electrical connector.
  5. Turn ON the ignition with the engine OFF.
  6. Command the EVAP vent valve ON and OFF with a scan tool.

Does the EVAP vent valve open and close?

--

Go to Step 5

Go to Step 6

5
  1. Remove the fresh air inlet cover from the EVAP canister.
  2. Inspect the fresh air inlet for a restriction or a blockage.
  3. Inspect the fresh air inlet filter for a restriction or a blockage.

Did you find and correct the condition?

--

Go to Step 9

Go to Step 7

6

Replace the EVAP vent valve. Refer to Evaporative Emission Canister Vent Solenoid Valve Replacement.

Did you complete the replacement?

--

Go to Step 9

--

7

Replace the EVAP canister. Refer to Evaporative Emission Canister Replacement.

Did you complete the replacement?

--

Go to Step 9

--

8

Replace the FTP sensor. Refer to Fuel Tank Pressure Sensor Replacement.

Did you complete the replacement?

--

Go to Step 9

--

9

Important: Do not exceed the specified value in this step. Exceeding the specified value may produce incorrect test results.

  1. Turn OFF the ignition.
  2. Connect all disconnected components.
  3. Connect the J 41413-200 Evaporative Emissions System Tester (EEST) power supply clips to a known good 12-volt source.

    4. Important: 

       • The GE-41415-50 fuel cap adapter, may not be available for the start of production. Once the J41415-50 is available, start the diagnosis at the fuel fill cap.
       • This vehicle may not be equipped with an EVAP service port. Connect the CH-48096 EVAP Service Port Access Tool between the EVAP purge solenoid and the EVAP purge pipe, if necessary.

  4. Install the nitrogen/smoke supply hose onto one of the following sources:
    5. • Connect the GE-41415-50 to the fuel fill pipe, and the J 41413-200 nitrogen/smoke supply hose to the fuel cap adapter.
    • Connect the J 41413-200 nitrogen/smoke supply hose to the EVAP service port.
  5. Turn ON the ignition.
  6. Command the EVAP vent solenoid closed with a scan tool.
  7. Turn the nitrogen/smoke valve on the J 41413-200 control panel to NITROGEN.
  8. Pressurize the EVAP system to the first specified value with the remote switch.
  9. Observe the fuel tank pressure sensor in H2O.
  10. Command the EVAP vent solenoid open with a scan tool.

Is the fuel tank pressure sensor parameter less than the second parameter?

5 in H2O

1 in H2O

Go to Step 10

Go to Step 2

10

Observe the Capture Info with a scan tool.

Are there any DTCs that have not been diagnosed?

--

Go to Diagnostic Trouble Code (DTC) List - Vehicle

System OK