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For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2005 🢒 Epica 🢒 Engine 🢒 Engine Controls - 2.5L (LBK) 🢒 DTC P0456

Circuit Description

The EVAP small leak test applies vacuum to the EVAP system and monitors vacuum decay. The control module monitors the fuel tank pressure sensor signal to determine the vacuum decay rate. At an appropriate time, the EVAP canister purge valve and the EVAP vent valve are turned ON. This allows the engine to draw vacuum on the EVAP system. After the desired vacuum level has been achieved, the EVAP purge valve is turned OFF, sealing the system. A leak is detected by monitoring for a decrease in the vacuum level during a given time period. If the system detects a leak larger than a calibrated amount, DTC P0456 will set.

DTC Descriptors

This diagnostic procedure supports the following DTC:

DTC P0456 Evaporative Emissions (EVAP) Very Small Leak Detected

Conditions for Running the DTC
    • DTCs P0106, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0131, P0132, P0133, P0137, P0138, P0140, P0261, P0262, P0264, P0265, P0267, P0268, P0270, P0271, P0273, P0274, P0276, P0277, P0300, P0402, P0404, P0405, P0406, P0452, P0453, P0462, P0463, P0501, P1449, and P2422 are not set.
    • The ignition 1 voltage is between 11-16 volts.
    • The barometric pressure (BARO) is more than 72 kPa.
    • The engine coolant temperature (ECT) is more than 70°C (158°F).
    • The estimated ambient air temperature is more than 9.75°C (50°C).
    • The purge enable time is more than 15 seconds.
    • The engine run time is more than 590 seconds.
    • The Fuel Tank Pressure is more than -1Kpa and less than .3 Kpa.
    • The fuel level is between 14-87%.
    • The engine is Idling.
    • The vehicle speed is less than 2 km/h (1 mph).
    • DTC P0456 runs once an ignition cycle when the above conditions are met.

Conditions for Setting the DTC

The EVAP system can achieve vacuum but a vacuum decay is detected 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 turns OFF the malfunction indicator lamp (MIL) after 3 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 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.

Test Description

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

  1. This step verifies that repairs are complete and that other conditions are not present.

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

Does the scan tool indicate DTC P0441, P0452, P0453, P1443, P1449, or P2422 are also set?

--

Go to Diagnostic Trouble Code (DTC) List

Go to Step 3

3
  1. Inspect the 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 canister purge 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:
    4. • Disconnected, improperly routed, kinked or damaged EVAP pipes and hoses
    • A damaged EVAP canister vent valve or EVAP canister

Did you find and correct the condition?

--

Go to Step 5

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 J 41415-30 to the fuel fill pipe.
  4. Connect the J 41413-200 Nitrogen/Smoke Supply Hose to the J 41415-30.
  5. Turn ON the ignition with the engine OFF.
  6. Turn the nitrogen/smoke valve on the J 41413-200 control panel to SMOKE.
  7. Disconnect the EVAP vent line from the vent solenoid, and seal it, using a suitable plug or a plug from the J 41413-300 EVAP Cap/Plug Kit.
  8. Use the remote switch to introduce smoke into the EVAP system.
  9. Use the J 41413-VLV EVAP Port Vent Fitting tool to open the EVAP service port.
  10. Remove the J 41413-VLV 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 5

Go to Diagnostic Aids

5

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. Install the J 41415-30 Fuel Tank Cap Adapter to the fuel fill pipe.
  6. Remove the nitrogen/smoke hose from the test orifice and install the hose onto the J 41415-30.
  7. Turn ON the ignition, with the engine OFF.
  8. With the vent still plugged, use the remote switch to introduce nitrogen and fill the EVAP system until the floating indicator stabilizes.
  9. 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 2

6

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