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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 1568 (Engine Controls Diagnostic (DTC P0172 To DTC P0455) -- 5.7L) >> Diagnosis >> DTC P0446 >> Diagnostic Aids

Diagnostic Aids

WARNING: This page is about a different car, the 2004 Chevrolet Corvette. However, it is still accessible from the selected car via links, so may be relevant.
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 Inspect the Evaporative Emission (EVAP) System for the following conditions:
Did you find and correct the condition?		 - Go to Step 15  Go to Step 3 
3
  1. Turn OFF the ignition.
  2. Disconnect the purge line from the EVAP canister vent 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 sensor parameter within the specified range?		 -1 to +1 in H2O Go to Step 4  Go to Step 9 
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. Connect the EVAP canister 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 Tank Cap Adapter or GE-41415-50 Interrupted Thread Fuel Tank Cap Adapter to the fuel fill pipe.
  5. Connect the fuel fill cap to the J 41415-40  or GE-41415-50 .
  6. Connect the J 41413-200  nitrogen/smoke supply hose to the J 41415-40  or GE-41415-50 .
  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 fuel tank pressure sensor in H2O with a scan tool.
  12. Command the EVAP canister vent solenoid valve 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 Step 5  Go to Step 7 
5
  1. Connect the nitrogen/smoke hose to the EVAP service port.
  2. Remove the J 41415-40  or GE-41415-50 .
  3. Install the fuel fill cap to the fuel fill pipe.
  4. Start the engine.
  5. Allow the engine to idle.
  6. Use the purge/seal function to seal the system with a scan tool.
  7. Command the EVAP canister purge solenoid valve to 30 percent.
  8. Observe the vacuum/pressure gage of the J 41413-200  and the FTP parameter on the scan tool.
  9. Allow the vacuum to increase on the gage of the J 41413-200  , until it reaches approximately 16 inch H2O.
  10. Use the purge/seal function to seal the system, with a scan tool.
Is the FTP parameter on a scan tool within the specified value of the vacuum/pressure gage on the J 41413-200  , until the vacuum reached the abort limit on a scan tool?		 1 in H2O Go to Step 6  Go to Step 9 
6 Did the FTP parameter on a scan tool display more than the specified value? 3.2 V Go to Diagnostic Aids Go to Step 9 
7 Disconnect the EVAP vent hose from the EVAP canister vent solenoid valve.
Is the fuel tank pressure sensor parameter less than the specified value?		 1 in H2O Go to Step 13  Go to Step 8 
8 Disconnect the EVAP canister vent hose from the EVAP canister.
Is the fuel tank pressure sensor parameter less than the specified value?		 1 in H2O Go to Step 11  Go to Step 14 
9 Test the low reference circuit of the fuel tank pressure (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 15  Go to Step 10 
10 Test for poor connections at the harness connector of 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 15  Go to Step 12 
11 Repair the pinched or restricted EVAP canister vent hose.
Did you complete the repair?		 - Go to Step 15  -
12 Replace the FTP sensor. Refer to Fuel Tank Pressure Sensor Replacement .
Did you complete the replacement?		 - Go to Step 15  -
13 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 15  -
14 Replace the EVAP canister. Refer to Evaporative Emission (EVAP) Canister Replacement .
Did you complete the replacement?		 - Go to Step 15  -
15
  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 sensor parameter within the specified range?		 -1 to +1 in H2O Go to Step 16  Go to Step 2 
16
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 all disconnected components.
  3. Connect the J 41413-200  to the fuel fill pipe.
  4. Turn ON the ignition, with the engine OFF
  5. Command the EVAP canister vent solenoid valve closed with a scan tool.
  6. Turn the nitrogen/smoke valve on the J 41413-200  control panel to NITROGEN.
  7. Use the remote switch to pressurize the EVAP system to the first specified value.
  8. Observe the fuel tank pressure sensor in H2O with a scan tool.
  9. Command the EVAP canister vent solenoid valve 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 Step 17  Go to Step 2 
17 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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