GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2007 🢒 STS 🢒 DTC 🢒 DTC P0455

System Description

The control module tests the evaporative emission (EVAP) system for a large leak. 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 increases too slowly, 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 procedure supports the following DTC:

DTC P0455 Evaporative Emission (EVAP) System Large Leak Detected

Conditions for Running the DTC
    • Before the engine control module (ECM) can report DTC P0455 failed, DTCs P0443, P0451, P0458, and P0459 must run and pass.
    • DTCs P0030, P0031, P0032, P0036, P0037, P0038, P0050, P0051, P0052, P0053, P0056, P0057, P0058, P0059, P0101, P0102, P0103, P0111, P0112, P0113, P116, P0117, P0118, P0119, P0121, P0122, P0123, P0125, P0130, P0131, P0132, P0133, P0135, P0137, P0138, P0140, P0141, P0150, P0151, P0152, P0153, P0155, P0157, P0158, P0160, P0161, P0221, P0222, P0223, P0443, P0449, P0451, P0452, P0453, P0458, P0459, P0496, P0498, P0499, P0506, P0507, P0560, P0562, P0563, P0721, P0722, P2122, P2123, P2127, P2128, P2138, P2177, P2178, P2179, P2180, P2187, P2188, P2189, P2190, P2195, P2196, P2197, P2198, P2227, P2228, P2229, P2232, P2235, P2237, P2240, P2243, P2247, P2251, P2254, P2270, P2271, P2272, P2273, P2297, P2298, P2626, and P2629 are not set.
    • The ignition 1 voltage is between 10.5-18 volts.
    • The engine run time is more than 10 minutes or the fuel trim is stable.
    • The fuel tank pressure is between -18.7 and 7.49 mm Hg (-10.0 and +4.0 inch H2O).
    • The fuel system is operating in Closed Loop.
    • The engine is idling.
    • The volumetric efficiency is less than 35 percent.
    • The barometric pressure (BARO) is more than 68 kPa.
    • The fuel level is between 12-88 percent.
    • The engine coolant temperature (ECT) is between 4-65°C (39-149°F).
    • The intake air temperature (IAT) is between 4-30°C (39-86°F).
    • The vehicle speed sensor (VSS) is less than 3 km/h (2 mph).
    • The above conditions are met for more than 11 seconds.
    • DTC P0455 will attempt to run up to 10 times or the test completes successfully once per ignition cycle.

Conditions For Setting the DTC
    • The ECM detects the EVAP system is not able to achieve or maintain vacuum during the diagnostic test.
    • The condition exists for more than 4 seconds.

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 turns OFF the malfunction indicator lamp (MIL) after 4 consecutive ignition cycles that the diagnostic runs and does not fail.
    • A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
    • A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
    • Clear the MIL and the DTC with a scan tool.

Diagnostic Aids
    • To help locate intermittent leaks, use the J 41413-200 Evaporative Emission 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.
    • A loose, incorrect, missing, or damaged fuel fill cap may cause this DTC to set.
    • 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.

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

    4.

  4. This step tests for a obstruction between the fuel tank and the FTP sensor, which is mounted on the EVAP canister, or a failed FTP sensor. Replace the FTP sensor if the pressure on the gage drops to near 0 inches H2O, with the sensor removed from the canister.

    5.

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

Step

Action

Values

Yes

No

Schematic Reference: Evaporative Emissions Hose Routing Diagram

1

Did you perform the Diagnostic System Check - Vehicle?

--

Go to Step 2

Go to Diagnostic System Check - Vehicle

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 (0.02 in) test orifice on the bottom-front of the J 41413-200 Evaporative Emission 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. Install the GE-41415-50 Fuel Tank Cap Adapter to the fuel fill pipe.
  6. Remove the nitrogen/smoke hose from the test orifice and install the hose and the fuel fill cap onto the GE-41415-50 .
  7. Turn ON the ignition, with the engine OFF.
  8. Command the evaporative emission (EVAP) vent solenoid closed with a scan tool.
  9. Use the remote switch to introduce nitrogen and fill the EVAP system until the floating indicator stabilizes.
  10. Compare the flow meter's stable floating indicator position to the red flag.

Is the floating indicator below the red flag?

--

Go to Step 7

Go to Step 3

3
  1. Inspect the EVAP system for the following conditions:
    2. • A loose, missing, or damaged service port schrader valve, if equipped
    • A loose, incorrect, missing, or damaged fuel fill cap
    • A damaged EVAP purge solenoid
  2. Raise the vehicle on a hoist. Refer to Lifting and Jacking the Vehicle .
  3. Inspect the EVAP system for the following conditions:
    4. • 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 20

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 power supply clips to a known good 12-volt source.
  3. Install the GE-41415-50 to the fuel fill pipe.
  4. Connect the J 41413-200 nitrogen/smoke supply hose and the vehicle fuel fill cap to the GE-41415-50 .
  5. Turn ON the ignition, with the engine OFF.
  6. Command the EVAP vent valve closed with a scan tool.
  7. Turn the nitrogen/smoke valve on the J 41413-200 control panel to SMOKE.
  8. Use the remote switch to introduce smoke into the EVAP system.
  9. Use the J 41413-VLV EVAP Service Port Vent Fitting Tool to open the EVAP service port, if equipped. Or, disconnect the EVAP purge pipe from the purge solenoid.
  10. Remove the J 41413-VLV , or reconnect the EVAP purge pipe once the 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 20

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. For vehicles without a service port, disconnect the purge tube at the quick connector on the EVAP canister side of the purge solenoid valve and install the CH-48096 EVAP Service Access Port Tool.
  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 .
  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 20

Go to Step 6

6

  1. Use the remote switch to stop introducing smoke.
  2. Install the GE-41415-50 to the fuel fill pipe.
  3. Connect the J 41413-200 nitrogen/smoke supply hose and vehicle fuel fill cap to the GE-41415-50 .
  4. Command the EVAP vent valve open with a scan tool.
  5. 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 parameter within the specified value of the J 41413-200 pressure/vacuum gage?

1 in H2O

Go to Step 7

Go to Step 17

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 inches H2O.
  4. Observe the Fuel Tank Pressure sensor parameter with a scan tool.

Is the FTP less than the specified value?

5 in H2O

Go to Step 8

Go to Step 9

8

  1. Remove the fuel tank pressure (FTP) sensor. Refer to Fuel Tank Pressure Sensor Replacement .
  2. Observe the pressure/vacuum gage on the J 41413-200 .

Did the J 41413-200 pressure/vacuum gage remain at the specified value?

10 in H2O

Go to Step 13

Go to Step 17

9

  1. Use the remote switch to stop introducing nitrogen into the EVAP system.
  2. Increase the EVAP purge solenoid to 100 percent with a scan tool.

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

5 in H2O

Go to Step 10

Go to Diagnostic Aids

10

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

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

5 in H2O

Go to Step 11

Go to Step 14

11

Disconnect the EVAP purge pipe from the EVAP purge solenoid.

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

5 in H2O

Go to Step 12

Go to Step 18

12

Disconnect the EVAP purge pipe at the EVAP canister.

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

5 in H2O

Go to Step 16

Go to Step 19

13
  1. Disconnect the EVAP vapor pipe at the EVAP canister.
  2. Observe the pressure/vacuum gage on the J 41413-200 .

Did the J 41413-200 pressure/vacuum gage remain at the specified value?

10 in H2O

Go to Step 15

Go to Step 19

14

Repair the pinched or obstructed EVAP purge solenoid vacuum source.

Did you complete the repair?

--

Go to Step 20

--

15

Repair the pinched or obstructed EVAP vapor pipe.

Did you complete the repair?

--

Go to Step 20

--

16

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 20

--

17

Replace the fuel tank pressure (FTP) sensor. Refer to Fuel Tank Pressure Sensor Replacement .

Did you complete the replacement?

--

Go to Step 20

--

18

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

Did you complete the replacement?

--

Go to Step 20

--

19

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

Did you complete the replacement?

--

Go to Step 20

--

20

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 (0.02 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. Install the GE-41415-50 to the fuel fill pipe.
  6. Remove the nitrogen/smoke hose from the test orifice and install the hose and the fuel fill cap onto the GE-41415-50 .
  7. Turn ON the ignition, with the engine OFF.
  8. Command the EVAP vent solenoid closed with a scan tool.
  9. Use the remote switch to introduce nitrogen and fill the EVAP system until the floating indicator stabilizes.
  10. 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

21
  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 - Vehicle

System OK