GM Service Manual Online
For 1990-2009 cars only
Table 1: DTC P0455 Evaporative Emission (EVAP) System Large Leak Detected

System Description

The DTC P0455 Evaporative Emission (EVAP) System Large Leak diagnostic detects large system leaks. The control module monitors the fuel tank pressure (FTP) sensor signal to determine the EVAP system vacuum level. When the conditions for running are met, the control module commands the EVAP canister purge valve OPEN and the EVAP vent valve CLOSED . This allows engine vacuum to enter the EVAP system. At a calibrated time, or vacuum level, the control module commands the EVAP canister purge valve closed, sealing the system, and monitors the FTP sensor input in order to determine the EVAP system vacuum level. If the system is unable to achieve the calibrated vacuum level, or the vacuum level decreases too rapidly, 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 Valve

EVAP Canister Vent Valve

ON

Open

Closed

OFF

Closed

Open

DTC Descriptor

This diagnostic supports the following DTC. DTC P0455 Evaporative Emission (EVAP) System Large Leak diagnostic

Conditions for Running the DTC

    • Before the PCM can report DTC P0455 failed, DTC P0107, P0108, P0117, P0118, P0451, P0452, P0453, P0496, P0498, P0499, P1128, P1129, P2199, P2227, P2228, and P2229 must run and pass.
    • The battery voltage is more than 10 volts.
    • The fuel system is operating in closed loop.
    • The fuel level is between 15-85 percent.
    • The difference between the initial intake air temperature (IAT) and the initial engine coolant temperature (ETC) is between 6-10°C (11-18°F).
    • The engine coolant temperature (ECT) is between 69-100°C (156-212°F).
    • The vehicle speed sensor (VSS) is between 12 km/h (7 mph) and 132 km/h (82 mph).
    • DTC P0455 runs once per drive cycle when the above conditions are met.

Conditions For Setting the DTC

The PCM detects the EVAP system is not able to achieve or maintain vacuum during the diagnostic test.

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 will turn the malfunction indicator lamp (MIL) OFF during the first consecutive trip in which the diagnostic has been run and passed.
    • A current DTC, Last Test Failed, clears when the control module turns OFF the MIL.
    • The history DTC will clear after the control module runs and passes 40 consecutive warm up cycles with no failure.
    • Use the scan tool in order to clear the DTC.

Diagnostic Aids

    • To help locate intermittent leaks, use the J 41413-200 Evaporative Emissions System Tester (EEST) to introduce smoke into the EVAP system. Move all EVAP components while observing smoke with the J 41413-SPT High Intensity White Light. Introducing smoke in 15 second intervals will allow less pressure into the EVAP system. When the system is less pressurized, the smoke will sometimes escape in a more condensed manner.
    • A temporary blockage in the EVAP purge solenoid, purge pipe or EVAP canister could cause an intermittent condition. Inspect and repair any restriction in the EVAP system.
    • To improve the visibility of the smoke exiting the EVAP system, observe the suspected leak area from different angles with the J 41413-SPT .
    • Observe the Freeze Frame/Failure Records vehicle mileage since the diagnostic test last failed may help determine how often the condition occurs that caused the DTC to set . This may assist in diagnosing the condition.
    • For an intermittent condition, refer to Intermittent Conditions .

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. Introducing smoke in 15 second intervals may allow smaller leak areas to be more noticeable. When the system is less pressurized, the smoke will sometimes escape in a more condensed manner.

  2. This step verifies proper operation of the FTP sensor.

  3. A normal operating FTP sensor should increase above 5 inches of H2O and stop between 6 inches of H2O and 7 inches of H2O.

  4. This step tests the EVAP purge solenoid vacuum source between the EVAP purge solenoid and the intake manifold for restrictions or blockages.

DTC P0455 Evaporative Emission (EVAP) System Large Leak Detected

Step

Action

Values

Yes

No

Schematic Reference: Evaporative Emissions 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

Important: Larger volume fuel tanks and/or those with lower fuel levels may require several minutes for the floating indicator to stabilize.

  1. Turn the nitrogen/smoke valve to nitrogen.
  2. Connect the nitrogen/smoke hose to the 0.5 mm (0.020 in) test orifice on the bottom-front of the J 41413-200 .
  3. Use the remote switch to activate the J 41413-200 .
  4. Align the red flag on the flow meter with the floating indicator. Use the remote switch to de-activate the J 41413-200 .
  5. Remove the nitrogen/smoke hose from the test orifice.
  6. Important: The GE-41415-50 fuel cap adapter, may not be available for the start of production. Once theGE-41415-50 is available, start the diagnosis at the fuel fill cap.

  7. Install the nitrogen/smoke supply hose onto one of the following sources:
  8. • 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.
  9. Turn ON the ignition, with the engine OFF.
  10. Command the EVAP vent solenoid closed with a scan tool.
  11. Use the remote switch to introduce nitrogen and fill the EVAP system until the floating stabilizes.
  12. 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 3

3

  1. Inspect the evaporative emission (EVAP) system for the following conditions:
  2. • Loose, missing, or damaged service port schrader valve
    • Loose, incorrect, missing, or damaged fuel fill cap
    • A damaged EVAP purge solenoid
  3. Raise the vehicle on a hoist. Refer to Lifting and Jacking the Vehicle in General Information.
  4. Inspect the EVAP system for the following conditions:
  5. • Disconnected, incorrectly routed, kinked, or damaged EVAP pipes and hoses
    • A damaged EVAP vent valve or EVAP canister

Did you find and correct the condition?

--

Go to Step 18

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. The 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. Important: The GE-41415-50 fuel cap adapter, may not be available for the start of production. Once theGE-41415-50 is available, start the diagnosis at the fuel fill cap.

  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.
  6. Turn ON the ignition with the engine OFF.
  7. Command the EVAP vent valve closed with a scan tool.
  8. Turn the nitrogen/smoke valve on the J 41413-200 control panel to SMOKE.
  9. Use the remote switch to introduce smoke into the EVAP system.
  10. Continue to introduce smoke into the EVAP system for 60 seconds.
  11. Inspect the entire EVAP system for exiting smoke with the J 41413-SPT High Intensity White Light.
  12. 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 19

Go to Step 5

5

  1. Disconnect the GE-41415-50 from the fuel fill pipe.
  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. Use the remote switch to introduce smoke into the EVAP system.
  5. Inspect the entire EVAP system for exiting smoke with the J 41413-SPT High Intensity White Light.
  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 19

Go to Step 6

6

  1. Use the remote switch to stop introducing smoke.
  2. Command the EVAP vent valve open with a scan tool.
  3. Compare the Fuel Tank Pressure parameter with a scan tool to the J 41413-200 pressure/vacuum gage.

Is the scan tool Fuel Tank Pressure sensor parameter within the specified value of the J 41413-200 pressure/vacuum gage?

1 in H2O

Go to Step 7

Go to Step 15

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. Use the J 41413-200 to pressurize the EVAP system to 10 in H2O.

Is the Fuel Tank Pressure sensor parameter more than the specified value?

5 in H2O

Go to Step 8

Go to Step 15

8

  1. Use the remote switch to stop introducing nitrogen into the EVAP system.
  2. Increase the EVAP purge solenoid to 20 percent.

Is the Fuel Tank Pressure sensor parameter less than the specified value?

1 in H2O

Go to Diagnostic Aids

Go to Step 9

9

Disconnect the EVAP purge vacuum source from the EVAP purge solenoid.

Is the Fuel Tank Pressure parameter less than the specified value?

1 in H2O

Go to Step 13

Go to Step 10

10

Disconnect the EVAP purge pipe from the EVAP purge solenoid.

Is the Fuel Tank Pressure parameter less than the specified value?

1 in H2O

Go to Step 16

Go to Step 11

11

Disconnect the EVAP purge pipe at the EVAP canister.

Is the Fuel Tank Pressure parameter less than the specified value?

1 in H2O

Go to Step 17

Go to Step 12

12

Disconnect the EVAP vapor pipe at the EVAP canister.

Is the Fuel Tank Pressure parameter less than the specified value?

1 in H2O

Go to Step 18

Go to Step 14

13

Repair the pinched or obstructed EVAP purge solenoid vacuum source.

Did you complete the repair?

 

Go to Step 19

--

14

Repair the pinched or obstructed EVAP vapor pipe.

Did you complete the repair?

--

Go to Step 19

--

15

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

Did you complete the replacement?

--

Go to Step 19

--

16

Replace the EVAP purge solenoid. Refer to Evaporative Emission Canister Purge Solenoid Valve Replacement .

Did you complete the replacement?

--

Go to Step 19

--

17

Repair the restriction in the EVAP purge pipe. Refer to Evaporative Emission Hoses/Pipes Replacement - Chassis/Canister .

Did you complete the repair?

--

Go to Step 19

--

18

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

Did you complete the replacement?

--

Go to Step 19

--

19

Important: Larger volume fuel tanks and/or those with lower fuel levels may require several minutes for the floating indicator to stabilize.

  1. Turn the nitrogen/smoke valve to nitrogen.
  2. Connect the nitrogen/smoke hose to the 0.5 mm (0.020 in) test orifice on the bottom-front of the J 41413-200 Evaporative Emissions System Tester (EEST).
  3. Use the remote switch to activate the J 41413-200 .
  4. Align the red flag on the flow meter with the floating indicator. Use the remote switch to de-activate the J 41413-200 .
  5. Remove the nitrogen/smoke hose from the test orifice.
  6. Important: The GE-41415-50 fuel cap adapter, may not be available for the start of production. Once the GE-41415-50 is available, start the diagnosis at the fuel fill cap.

  7. Install the nitrogen/smoke supply hose onto one of the following sources:
  8. • 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.
  9. Turn ON the ignition, with the engine OFF.
  10. Command the EVAP vent solenoid closed with a scan tool.
  11. Use the remote switch to introduce nitrogen and fill the EVAP system until the floating indicator stabilizes.
  12. Compare the flow meter's stable floating indicator position to the red flag.

Is the floating indicator below the red flag?

--

Go to Step 20

Go to Step 4

20

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