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Test Description

WARNING: This page is about a different car, the 2004 Buick Rendezvous. However, it is still accessible from the selected car via links, so may be relevant.
  1. 3:  This step tests the operation of the FTP sensor. If the FTP parameter is more or less than an atmospheric value when the purge hose is disconnected from the purge solenoid, replace the FTP sensor.
  2. 4:  This step tests for a restriction in the EVAP vent system. If the FTP sensor parameter does not return to the second value there is a restriction in the vent system.
DTC P0446 Evaporative Emission (EVAP) Vent System Performance

Step Action Values Yes No
Schematic Reference:  Evaporative Emissions (EVAP) Hose Routing Diagram 
1 Did you perform the Diagnostic System Check - Engine Controls? - Go to Step 2  Go to Diagnostic System Check - Engine Controls
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 sensor 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 7 
4 
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. Reconnect the EVAP purge pipe.
  3. Connect the J 41413-200  Evaporative Emissions System Tester (EEST) power supply clips to a known good 12-volt source.
  4. Install the J 41415-40  Fuel Fill Cap Adapter to the fuel fill pipe.
  5. Connect the fuel fill cap to the J 41415-40  .
  6. Connect the J 41413-200  nitrogen/smoke supply hose to the J 41415-40  .
  7. Turn ON the ignition, with the engine OFF.
    8. IMPORTANT: The DTCs may need to be cleared if the output control does not operate.
  8. Command the EVAP vent valve closed with a scan tool.
  9. Turn the nitrogen/smoke valve on the J 41413-200  control panel to NITROGEN.
  10. Use the remote switch to pressurize the EVAP system to the first specified value.
  11. Observe the Fuel Tank Pressure sensor parameter with a scan tool.
  12. Command the EVAP vent solenoid open with a scan tool.
Is the Fuel Tank Pressure sensor parameter less than the second specified value?		 5 in H2O
1 in H2O		 Go to Diagnostic Aids Go to Step 5 
5 Disconnect the EVAP vent hose from the EVAP vent valve solenoid. Refer to Evaporative Emission (EVAP) Canister Vent Solenoid Valve Replacement
Is the Fuel Tank Pressure sensor parameter less than the specified value?		 1 in H2O Go to Step 9  Go to Step 6 
6 Disconnect the EVAP vent hose from the EVAP canister. Refer to Evaporative Emission (EVAP) Canister Replacement .
Is the Fuel Tank Pressure sensor parameter less than the specified value?		 1 in H2O Go to Step 8  Go to Step 10 
7 Test for an intermittent and for a poor connection at the fuel tank pressure (FTP) and at the engine control module (ECM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 12  Go to Step 11 
8 Repair the pinched or restricted EVAP vent hose.
Did you complete the repair?		 - Go to Step 12  -
9 Replace the EVAP vent valve solenoid. Refer to Evaporative Emission (EVAP) Canister Vent Solenoid Valve Replacement .
Did you complete the replacement?		 - Go to Step 12  -
10 Replace the EVAP canister. Refer to Evaporative Emission (EVAP) Canister Replacement .
Did you complete the replacement?		 - Go to Step 12  -
11 Replace the (FTP) sensor. Refer to Fuel Tank Pressure Sensor Replacement .
Did you complete the replacement?		 - Go to Step 12  -
12
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  power supply clips to a known good 12-volt source.
  4. Install the J 41415-40  to the fuel fill pipe.
  5. Connect the J 41413-200  nitrogen/smoke supply hose to the J 41415-40  .
  6. Turn ON the ignition, with the engine OFF.
    7. IMPORTANT: The DTCs may need to be cleared if the output control does not operate.
  7. Command the EVAP vent solenoid closed with a scan tool.
  8. Turn the nitrogen/smoke valve on the J 41413-200  control panel to NITROGEN.
  9. Use the remote switch to pressurize the EVAP system to the first specified value.
  10. Observe the Fuel Tank Pressure sensor parameter with a scan tool.
    11. IMPORTANT: The DTCs may need to be cleared if the output control does not operate.
  11. 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 13  Go to Step 2 
13
  1. Clear the DTCs with a scan tool.
  2. Observe the Capture Info with a scan tool.
Are there any DTCs that have not been diagnosed?		 Go to Diagnostic Trouble Code (DTC) List System OK
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