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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 1159 (Engine Controls Diagnosis - 3.4L (DTC P0140-DTC P0496)) >> Diagnostic Trouble Codes >> DTC P0446 >> Test Description

Test Description

WARNING: This page is about a different car, the 2004 Pontiac Aztek and 2004 Buick Rendezvous. However, it is still accessible from the selected car via links, so may be relevant.

The number below refers to the step number on the diagnostic table.

  1. 4:  This test determines if the failure is present or intermittent.
DTC P0446

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
  1. Observe the Freeze Frame/Failure Records for this DTC.
  2. Perform the Service Bay Test. Refer to Service Bay Test .
Does the scan tool indicate that the Service Bay Test passed?		 - Go to Diagnostic Aids Go to Step 3 
3 Inspect the evaporative emission (EVAP) system for the following conditions:
Did you find and correct the condition?		 - Go to Step 14  Go to Step 4 
4 
  1. Turn OFF the ignition.
  2. Disconnect the purge line from the EVAP canister purge solenoid valve. Refer to Evaporative Emission (EVAP) Canister Purge Solenoid Valve Replacement .
  3. Turn ON the ignition, with the engine OFF.
Is the fuel tank pressure (FTP) sensor parameter within the specified range?		 -1 to + 1 in H20 Go to Step 5  Go to Step 9 
5
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. Command the EVAP canister vent solenoid 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 FTP sensor parameter with a scan tool.
  12. Command the EVAP canister vent solenoid valve OPEN with a scan tool.
Is the FTP sensor parameter less than the second specified value?		 5 in H2O
1 in H2O		 Go to Diagnostic Aids Go to Step 6 
6 Disconnect the EVAP vent hose from the EVAP canister vent solenoid valve.
Is the FTP sensor parameter less than the specified value?		 1 in H2O Go to Step 12  Go to Step 7 
7 Disconnect the EVAP vent hose from the EVAP canister.
Is the FTP sensor parameter less than the specified value?		 1 in H2O Go to Step 8  Go to Step 13 
8 Repair the pinched or restricted EVAP vent hose.
Did you complete the repair?		 - Go to Step 14  -
9 Test for an intermittent and for a poor connection at the FTP sensor. 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 14  Go to Step 10 
10 Test the low reference circuit of the FTP sensor for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 14  Go to Step 11 
11 Replace the FTP sensor. Refer to Fuel Tank Pressure Sensor Replacement .
Did you complete the replacement?		 - Go to Step 14  -
12 Replace the EVAP canister vent solenoid valve. Refer to Evaporative Emission (EVAP) Canister Vent Solenoid Valve Replacement .
Did you complete the replacement?		 - Go to Step 14  -
13 Replace the EVAP canister. Refer to Evaporative Emission (EVAP) Canister Replacement .
Did you complete the replacement?		 - Go to Step 14  -
14 Perform the Service Bay Test. Refer to Service Bay Test .
Does the scan tool indicate that the Service Bay Test passed?		 - Go to Step 15  Go to Step 3 
15 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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