P0455

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 table illustrates the relationship between the ON and OFF states, and the OPEN or CLOSED states of the EVAP canister purge and vent valves.

DTC DESCRIPTOR
This diagnostic procedure supports the following DTC:
DTC P0455 Evaporative Emission (EVAP) System Large Leak Detected

CONDITIONS FOR RUNNING THE DTC
- DTCs P0106, P0107, P0108, P112, P0113, P0117, P0118, P0122, P0123, P0131, P0132, P0133, P0134, P0137, P0138, P0140, P0141, P0201, P0202, P0203, P0204 P0402, P0404, P0405, P0406, P0443, P0452, P0453, P0462, P0463, P0488, P0502, P2195, and P2196 are not set.
- The barometric pressure (BARO) is more than 72 kPa.
- The engine coolant temperature (ECT) at start-up is more than - 5°C (23°F).
- The intake air temperature (IAT) at start-up is less than 40°C (104°F).
- The start-up IAT minus the startup ECT is within 12°C (22°F).
- The start-up ECT minus startup IAT is within 50°C (90°F).
- The start-up IAT minus IAT are within 3°C (5°F).
- The ignition 1 voltage is between 11-16 volts.
- Purge start time is less than 360 seconds.
- Engine Run Time is more than 1 second and less than 120 seconds.
- DTC P0441 runs once an ignition cycle when the above conditions are met.

CONDITIONS FOR SETTING THE DTC
The ECM 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 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.
- 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. Intermittent Conditions

TEST DESCRIPTION

Step 1:

Step 2:

Step 3:

Step 4:

Steps 5-6:

Steps 7-12:

Steps 13-18:

Steps 19-20:

The numbers below refer to the step numbers on the diagnostic table.
4. 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.
6. This step verifies proper operation of the FTP sensor.
7. A normal operating FTP sensor should increase above 5 inches H20 and stop between 6 inches H20 and 7 inches H20.
9. This step tests the EVAP purge solenoid vacuum source between the EVAP purge solenoid and the Intake manifold for restrictions or blockages.