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Home >> Buick >> 2006 >> Allure CX >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - 3.8L - DTC P0451 To DTC P2120 >> DTC P0455 >> Test Description
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Test Description

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

  1. 6:  A normal operating FTP sensor should increase above 5 inches of H2O and stop between 6 inches of H2O and 7 inches of H2O.
DTC P0455

Step Action Values Yes No
Schematic Reference:  Evaporative Emissions (EVAP) Hose Routing Diagram 
Connector End View Reference: Powertrain Control Module (PCM) Connector End Views or Engine Controls Connector End Views
1 Did you perform the Diagnostic System Check - Vehicle? - Go to Step 2  Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2
  1. Inspect the evaporative emission (EVAP) system for the following conditions:
    • Loose, missing or damaged service port Schrader valve
    • Loose, incorrect, missing or damaged fuel fill cap
    • A damaged EVAP canister purge solenoid valve
  2. Raise the vehicle on a hoist. Refer to Lifting and Jacking the Vehicle in General Information.
  3. Inspect the EVAP system for the following conditions:
    • Disconnected, improperly routed, kinked or damaged EVAP pipes and hoses
    • A damaged EVAP canister vent solenoid valve or EVAP canister
Did you find and correct the condition?		 - Go to Step 21  Go to Step 3 
3
IMPORTANT: Larger volume fuel tanks and/or those with lower fuel levels may require several minutes for the floating indicator to stabilize.
  1. Turn OFF the ignition.
  2. Connect the J 41413-200  Evaporative Emissions System Tester (EEST) power supply clips to a known good 12-volt source.
  3. Turn the nitrogen/smoke valve to nitrogen.
  4. Connect the nitrogen/smoke hose to the 0.5 mm (0.20 in) test orifice on the bottom-front of the J 41413-200  .
  5. Use the remote switch to activate the J 41413-200  .
  6. Align the red flag on the flow meter with the floating indicator. Use the remote switch to de-activate the J 41413-200  .
  7. Install the J 41415-40  Fuel Tank Cap Adapter to the fuel fill pipe. See Special Tools .
  8. Install the fuel fill cap to the J 41415-40  . See Special Tools .
  9. Remove the nitrogen/smoke hose from the test orifice and install the hose onto the J 41415-40  . See Special Tools .
  10. Turn ON the ignition, with the engine OFF.
  11. Command the EVAP vent solenoid closed with a scan tool.
  12. Use the remote switch to introduce nitrogen and fill the EVAP system until the floating indicator stabilizes.
  13. Compare the flow meter's stable floating indicator position to the red flag.
Is the floating indicator below the red flag?		 - Go to Step 6  Go to Step 4 
4
IMPORTANT: Ensure that the vehicle underbody temperature is similar to the ambient temperature and allow the surrounding air to stabilize before starting the diagnostic procedure. System flow will be less with higher temperatures.
  1. Turn OFF the ignition.
  2. Connect the J 41413-200  Evaporative Emissions System Tester (EEST) power supply clips to a known good 12-volt source.
  3. Install the J 41415-40  Fuel Tank Cap Adapter to the fuel fill pipe. See Special Tools .
  4. Connect the J 41413-200  nitrogen/smoke supply hose to the J 41415-40  . See Special Tools .
  5. Turn ON the ignition, with the engine OFF
  6. Command the EVAP canister vent solenoid valve closed with a scan tool.
  7. Turn the nitrogen/smoke valve on the J 41413-200  control panel to SMOKE.
  8. Introduce smoke into the EVAP system with the remote switch.
  9. Open the EVAP service port with the J 41413-VLV  EVAP Port Vent Fitting.
  10. Remove the J 41413-VLV  once smoke is observed.
  11. Continue to introduce smoke into the EVAP system for an additional 60 seconds.
  12. Inspect the entire EVAP system for exiting smoke with the J 41413-SPT  High Intensity White Light.
  13. Continue to introduce smoke at 15 second intervals until the leak source has been located.
Did you locate and repair a leak source?		 - Go to Step 16  Go to Step 5 
5
  1. Disconnect the J 41415-40  from the fuel fill pipe. See Special Tools .
  2. Install the fuel fill cap to the fuel fill pipe.
  3. Connect the J 41413-200  nitrogen/smoke supply hose to the EVAP service port.
  4. Introduce smoke into the EVAP system with the remote switch.
  5. Inspect the entire EVAP system for exiting smoke with the J 41413-SPT  .
  6. Continue to introduce smoke at 15 second intervals until the leak source has been located.
Did you locate and repair a leak source?		 - Go to Step 21  Go to Step 6 
6 
  1. Stop introducing smoke with the remote switch.
  2. Install the J 41415-40  to the fuel fill pipe. See Special Tools .
  3. Connect the J 41413-200  nitrogen/smoke supply hose and vehicle fuel fill cap to the J 41415-40  . See Special Tools .
  4. Command the EVAP canister vent solenoid valve open with a scan tool.
  5. Compare the fuel tank pressure sensor parameter with a scan tool to the J 41413-200  pressure/vacuum gage.
Is the difference between the two gages less than the specified value?		 1 in H2O Go to Step 7  Go to Step 16 
7
  1. Seal the EVAP system using the EVAP Purge/Seal function with a scan tool.
  2. Turn the nitrogen/smoke valve on the J 41413-200  control panel to NITROGEN.
  3. Pressurize the EVAP system to the first specified value with the J 41413-200  .
  4. Observe the fuel tank pressure sensor parameter with a scan tool.
Is the fuel tank pressure sensor parameter more than the second specified value?		 10 in H2O
5 in H2O		 Go to Step 8  Go to Step 16 
8
  1. Stop introducing nitrogen into the EVAP system with the remote switch.
  2. Increase the EVAP canister purge solenoid valve to 100 percent.
  3. Observe the fuel tank pressure sensor parameter with a scan tool.
Is the fuel tank pressure sensor parameter less than the specified value?		 1 in H2O Go to Step 9  Go to Step 11 
9
  1. Connect the nitrogen/smoke hose to the EVAP service port.
  2. Remove the J 41415-40  . See Special Tools .
  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 purge solenoid to 30 percent.
  8. Observe the vacuum/pressure gage on 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 in H2O.
  10. Use the purge/seal function to seal the system with a scan tool.
Is the FTP parameter on the 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 10  Go to Step 16 
10 Did the FTP parameter on a scan tool display more than the specified value? 3.2 V Go to Diagnostic Aids Go to Step 16 
11 Disconnect the EVAP purge pipe from the EVAP canister purge solenoid valve.
Is the fuel tank pressure sensor parameter less than the specified value within 90 seconds?		 1 in H2O Go to Step 19  Go to Step 12 
12 Disconnect the EVAP purge pipe at the EVAP canister.
Is the fuel tank pressure sensor parameter less than the specified value?		 1 in H2O Go to Step 15  Go to Step 13 
13 Disconnect the EVAP vapor pipe at the EVAP canister.
Is the fuel tank pressure sensor parameter less than the specified value?		 1 in H2O Go to Step 20  Go to Step 14 
14 Repair the pinched or obstructed EVAP vapor pipe.
Did you complete the repair?		 - Go to Step 21  -
15 Repair the restriction in the EVAP purge pipe.
Did you complete the repair?		 - Go to Step 21  -
16 Test for an intermittent and for a poor connection at the fuel tank pressure (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 21  Go to Step 17 
17 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 21  Go to Step 18 
18 Replace the FTP sensor. Refer to Fuel Tank Pressure Sensor Replacement .
Did you complete the replacement?		 - Go to Step 21  -
19 Replace the EVAP canister purge solenoid valve. Refer to Evaporative Emission (EVAP) Canister Purge Solenoid Valve Replacement .
Did you complete the replacement?		 - Go to Step 21  -
20 Replace the EVAP canister. Refer to Evaporative Emission (EVAP) Canister Replacement .
Did you complete the replacement?		 - Go to Step 21  -
21
IMPORTANT: DO NOT exceed the specified value in this step. Exceeding the specified value may produce incorrect test results.
  1. Connect the J 41413-200  to the fuel fill pipe.
  2. Turn the nitrogen/smoke valve to NITROGEN.
  3. Seal the EVAP system using the EVAP Purge/Seal function with a scan tool.
  4. Pressurize the EVAP system to the specified value.
  5. Observe the J 41413-200  pressure/vacuum gage for 5 minutes.
Does the J 41413-200  pressure/vacuum gage remain constant?		 5 in H2O Go to Step 22  Go to Step 4 
22 Compare the fuel tank pressure sensor parameter with a scan tool to the J 41413-200  pressure/vacuum gage.
Is the difference between the two gages less than the specified value?		 1 in H2O Go to Step 23  Go to Step 6 
23
  1. Observe the J 41413-200  pressure/vacuum gage.
  2. Increase the EVAP canister purge solenoid valve to 100 percent.
Does the pressure decrease?		 - Go to Step 24  Go to Step 9 
24 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 in Vehicle DTC Information System OK
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