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 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.
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. Intermittent Conditions
Test Description
Step 1 - Step 3:
Step 4 - Step 7:
Step 8 - Step 19:
Step 20 - Step 21:
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 of H2O and stop between 6-7 inches of H2O.
8. 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.
10. This step tests the EVAP purge solenoid vacuum source between the EVAP purge solenoid and the intake manifold for restrictions or blockages.